#!/usr/bin/perl

# vim: tw=160:nowrap:expandtab:tabstop=3:shiftwidth=3:softtabstop=3

# This program is copyright (c) 2006 Baron Schwartz, baron at xaprb dot com.
# Feedback and improvements are gratefully received.
#
# THIS PROGRAM IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
# WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
# MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation, version 2; OR the Perl Artistic License.  On UNIX and similar
# systems, you can issue `man perlgpl' or `man perlartistic' to read these

# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc., 59 Temple
# Place, Suite 330, Boston, MA  02111-1307  USA

use strict;
use warnings FATAL => 'all';

our $VERSION = '1.7.1';

# Find the home directory; it's different on different OSes.
our $homepath = $ENV{HOME} || $ENV{HOMEPATH} || $ENV{USERPROFILE} || '.';

# Configuration files
our $default_home_conf = "$homepath/.innotop/innotop.conf";
our $default_central_conf = "/etc/innotop/innotop.conf";
our $conf_file = "";

## Begin packages ##

package DSNParser;

use DBI;
use Data::Dumper;
$Data::Dumper::Indent    = 0;
$Data::Dumper::Quotekeys = 0;
use English qw(-no_match_vars);

use constant MKDEBUG => $ENV{MKDEBUG};

# Defaults are built-in, but you can add/replace items by passing them as
# hashrefs of {key, desc, copy, dsn}.  The desc and dsn items are optional.
# You can set properties with the prop() sub.  Don't set the 'opts' property.
sub new {
   my ( $class, @opts ) = @_;
   my $self = {
      opts => {
         A => {
            desc => 'Default character set',
            dsn  => 'charset',
            copy => 1,
         },
         D => {
            desc => 'Database to use',
            dsn  => 'database',
            copy => 1,
         },
         F => {
            desc => 'Only read default options from the given file',
            dsn  => 'mysql_read_default_file',
            copy => 1,
         },
         h => {
            desc => 'Connect to host',
            dsn  => 'host',
            copy => 1,
         },
         p => {
            desc => 'Password to use when connecting',
            dsn  => 'password',
            copy => 1,
         },
         P => {
            desc => 'Port number to use for connection',
            dsn  => 'port',
            copy => 1,
         },
         S => {
            desc => 'Socket file to use for connection',
            dsn  => 'mysql_socket',
            copy => 1,
         },
         u => {
            desc => 'User for login if not current user',
            dsn  => 'user',
            copy => 1,
         },
      },
   };
   foreach my $opt ( @opts ) {
      MKDEBUG && _d('Adding extra property ' . $opt->{key});
      $self->{opts}->{$opt->{key}} = { desc => $opt->{desc}, copy => $opt->{copy} };
   }
   return bless $self, $class;
}

# Recognized properties:
# * autokey:   which key to treat a bareword as (typically h=host).
# * dbidriver: which DBI driver to use; assumes mysql, supports Pg.
# * required:  which parts are required (hashref).
# * setvars:   a list of variables to set after connecting
sub prop {
   my ( $self, $prop, $value ) = @_;
   if ( @_ > 2 ) {
      MKDEBUG && _d("Setting $prop property");
      $self->{$prop} = $value;
   }
   return $self->{$prop};
}

sub parse {
   my ( $self, $dsn, $prev, $defaults ) = @_;
   if ( !$dsn ) {
      MKDEBUG && _d('No DSN to parse');
      return;
   }
   MKDEBUG && _d("Parsing $dsn");
   $prev     ||= {};
   $defaults ||= {};
   my %given_props;
   my %final_props;
   my %opts = %{$self->{opts}};
   my $prop_autokey = $self->prop('autokey');

   # Parse given props
   foreach my $dsn_part ( split(/,/, $dsn) ) {
      if ( my ($prop_key, $prop_val) = $dsn_part =~  m/^(.)=(.*)$/ ) {
         # Handle the typical DSN parts like h=host, P=3306, etc.
         $given_props{$prop_key} = $prop_val;
      }
      elsif ( $prop_autokey ) {
         # Handle barewords
         MKDEBUG && _d("Interpreting $dsn_part as $prop_autokey=$dsn_part");
         $given_props{$prop_autokey} = $dsn_part;
      }
      else {
         MKDEBUG && _d("Bad DSN part: $dsn_part");
      }
   }

   # Fill in final props from given, previous, and/or default props
   foreach my $key ( keys %opts ) {
      MKDEBUG && _d("Finding value for $key");
      $final_props{$key} = $given_props{$key};
      if (   !defined $final_props{$key}
           && defined $prev->{$key} && $opts{$key}->{copy} )
      {
         $final_props{$key} = $prev->{$key};
         MKDEBUG && _d("Copying value for $key from previous DSN");
      }
      if ( !defined $final_props{$key} ) {
         $final_props{$key} = $defaults->{$key};
         MKDEBUG && _d("Copying value for $key from defaults");
      }
   }

   # Sanity check props
   foreach my $key ( keys %given_props ) {
      die "Unrecognized DSN part '$key' in '$dsn'\n"
         unless exists $opts{$key};
   }
   if ( (my $required = $self->prop('required')) ) {
      foreach my $key ( keys %$required ) {
         die "Missing DSN part '$key' in '$dsn'\n" unless $final_props{$key};
      }
   }

   return \%final_props;
}

sub as_string {
   my ( $self, $dsn ) = @_;
   return $dsn unless ref $dsn;
   return join(',',
      map  { "$_=" . ($_ eq 'p' ? '...' : $dsn->{$_}) }
      grep { defined $dsn->{$_} && $self->{opts}->{$_} }
      sort keys %$dsn );
}

sub usage {
   my ( $self ) = @_;
   my $usage
      = "DSN syntax is key=value[,key=value...]  Allowable DSN keys:\n"
      . "  KEY  COPY  MEANING\n"
      . "  ===  ====  =============================================\n";
   my %opts = %{$self->{opts}};
   foreach my $key ( sort keys %opts ) {
      $usage .= "  $key    "
             .  ($opts{$key}->{copy} ? 'yes   ' : 'no    ')
             .  ($opts{$key}->{desc} || '[No description]')
             . "\n";
   }
   if ( (my $key = $self->prop('autokey')) ) {
      $usage .= "  If the DSN is a bareword, the word is treated as the '$key' key.\n";
   }
   return $usage;
}

# Supports PostgreSQL via the dbidriver element of $info, but assumes MySQL by
# default.
sub get_cxn_params {
   my ( $self, $info ) = @_;
   my $dsn;
   my %opts = %{$self->{opts}};
   my $driver = $self->prop('dbidriver') || '';
   if ( $driver eq 'Pg' ) {
      $dsn = 'DBI:Pg:dbname=' . ( $info->{D} || '' ) . ';'
         . join(';', map  { "$opts{$_}->{dsn}=$info->{$_}" }
                     grep { defined $info->{$_} }
                     qw(h P));
   }
   else {
      $dsn = 'DBI:mysql:' . ( $info->{D} || '' ) . ';'
         . join(';', map  { "$opts{$_}->{dsn}=$info->{$_}" }
                     grep { defined $info->{$_} }
                     qw(F h P S A))
         . ';mysql_read_default_group=client';
   }
   MKDEBUG && _d($dsn);
   return ($dsn, $info->{u}, $info->{p});
}


# Fills in missing info from a DSN after successfully connecting to the server.
sub fill_in_dsn {
   my ( $self, $dbh, $dsn ) = @_;
   my $vars = $dbh->selectall_hashref('SHOW VARIABLES', 'Variable_name');
   my ($user, $db) = $dbh->selectrow_array('SELECT USER(), DATABASE()');
   $user =~ s/@.*//;
   $dsn->{h} ||= $vars->{hostname}->{Value};
   $dsn->{S} ||= $vars->{'socket'}->{Value};
   $dsn->{P} ||= $vars->{port}->{Value};
   $dsn->{u} ||= $user;
   $dsn->{D} ||= $db;
}

sub get_dbh {
   my ( $self, $cxn_string, $user, $pass, $opts ) = @_;
   $opts ||= {};
   my $defaults = {
      AutoCommit        => 0,
      RaiseError        => 1,
      PrintError        => 0,
      mysql_enable_utf8 => ($cxn_string =~ m/charset=utf8/ ? 1 : 0),
   };
   @{$defaults}{ keys %$opts } = values %$opts;
   my $dbh;
   my $tries = 2;
   while ( !$dbh && $tries-- ) {
      eval {
         MKDEBUG && _d($cxn_string, ' ', $user, ' ', $pass, ' {',
            join(', ', map { "$_=>$defaults->{$_}" } keys %$defaults ), '}');
         $dbh = DBI->connect($cxn_string, $user, $pass, $defaults);
         # Immediately set character set and binmode on STDOUT.
         if ( my ($charset) = $cxn_string =~ m/charset=(\w+)/ ) {
            my $sql = "/*!40101 SET NAMES $charset*/";
            MKDEBUG && _d("$dbh: $sql");
            $dbh->do($sql);
            MKDEBUG && _d('Enabling charset for STDOUT');
            if ( $charset eq 'utf8' ) {
               binmode(STDOUT, ':utf8')
                  or die "Can't binmode(STDOUT, ':utf8'): $OS_ERROR";
            }
            else {
               binmode(STDOUT) or die "Can't binmode(STDOUT): $OS_ERROR";
            }
         }
      };
      if ( !$dbh && $EVAL_ERROR ) {
         MKDEBUG && _d($EVAL_ERROR);
         if ( $EVAL_ERROR =~ m/not a compiled character set|character set utf8/ ) {
            MKDEBUG && _d("Going to try again without utf8 support");
            delete $defaults->{mysql_enable_utf8};
         }
         if ( !$tries ) {
            die $EVAL_ERROR;
         }
      }
   }
   # If setvars exists and it's MySQL connection, set them
   my $setvars = $self->prop('setvars');
   if ( $cxn_string =~ m/mysql/i && $setvars ) {
      my $sql = "SET $setvars";
      MKDEBUG && _d("$dbh: $sql");
      eval {
         $dbh->do($sql);
      };
      if ( $EVAL_ERROR ) {
         MKDEBUG && _d($EVAL_ERROR);
      }
   }
   MKDEBUG && _d('DBH info: ',
      $dbh,
      Dumper($dbh->selectrow_hashref(
         'SELECT DATABASE(), CONNECTION_ID(), VERSION()/*!50038 , @@hostname*/')),
      ' Connection info: ', ($dbh->{mysql_hostinfo} || 'undef'),
      ' Character set info: ',
      Dumper($dbh->selectall_arrayref(
         'SHOW VARIABLES LIKE "character_set%"', { Slice => {}})),
      ' $DBD::mysql::VERSION: ', $DBD::mysql::VERSION,
      ' $DBI::VERSION: ', $DBI::VERSION,
   );
   return $dbh;
}

# Tries to figure out a hostname for the connection.
sub get_hostname {
   my ( $self, $dbh ) = @_;
   if ( my ($host) = ($dbh->{mysql_hostinfo} || '') =~ m/^(\w+) via/ ) {
      return $host;
   }
   my ( $hostname, $one ) = $dbh->selectrow_array(
      'SELECT /*!50038 @@hostname, */ 1');
   return $hostname;
}

# Disconnects a database handle, but complains verbosely if there are any active
# children.  These are usually $sth handles that haven't been finish()ed.
sub disconnect {
   my ( $self, $dbh ) = @_;
   MKDEBUG && $self->print_active_handles($dbh);
   $dbh->disconnect;
}

sub print_active_handles {
   my ( $self, $thing, $level ) = @_;
   $level ||= 0;
   printf("# Active %sh: %s %s %s\n", ($thing->{Type} || 'undef'), "\t" x $level,
      $thing, (($thing->{Type} || '') eq 'st' ? $thing->{Statement} || '' : ''))
      or die "Cannot print: $OS_ERROR";
   foreach my $handle ( grep {defined} @{ $thing->{ChildHandles} } ) {
      $self->print_active_handles( $handle, $level + 1 );
   }
}

sub _d {
   my ($package, undef, $line) = caller 0;
   @_ = map { (my $temp = $_) =~ s/\n/\n# /g; $temp; }
        map { defined $_ ? $_ : 'undef' }
        @_;
   # Use $$ instead of $PID in case the package
   # does not use English.
   print "# $package:$line $$ ", @_, "\n";
}

1;

package InnoDBParser;

use Data::Dumper;
$Data::Dumper::Sortkeys = 1;
use English qw(-no_match_vars);
use List::Util qw(max);

# Some common patterns
my $d  = qr/(\d+)/;                    # Digit
my $f  = qr/(\d+\.\d+)/;               # Float
my $t  = qr/(\d+ \d+)/;                # Transaction ID
my $i  = qr/((?:\d{1,3}\.){3}\d+)/;    # IP address
my $n  = qr/([^`\s]+)/;                # MySQL object name
my $w  = qr/(\w+)/;                    # Words
my $fl = qr/([\w\.\/]+) line $d/;      # Filename and line number
my $h  = qr/((?:0x)?[0-9a-f]*)/;       # Hex
my $s  = qr/(\d{6} .\d:\d\d:\d\d)/;    # InnoDB timestamp

# If you update this variable, also update the SYNOPSIS in the pod.
my %innodb_section_headers = (
   "TRANSACTIONS"                          => "tx",
   "BUFFER POOL AND MEMORY"                => "bp",
   "SEMAPHORES"                            => "sm",
   "LOG"                                   => "lg",
   "ROW OPERATIONS"                        => "ro",
   "INSERT BUFFER AND ADAPTIVE HASH INDEX" => "ib",
   "FILE I/O"                              => "io",
   "LATEST DETECTED DEADLOCK"              => "dl",
   "LATEST FOREIGN KEY ERROR"              => "fk",
);

my %parser_for = (
   tx => \&parse_tx_section,
   bp => \&parse_bp_section,
   sm => \&parse_sm_section,
   lg => \&parse_lg_section,
   ro => \&parse_ro_section,
   ib => \&parse_ib_section,
   io => \&parse_io_section,
   dl => \&parse_dl_section,
   fk => \&parse_fk_section,
);

my %fk_parser_for = (
   Transaction => \&parse_fk_transaction_error,
   Error       => \&parse_fk_bad_constraint_error,
   Cannot      => \&parse_fk_cant_drop_parent_error,
);

# A thread's proc_info can be at least 98 different things I've found in the
# source.  Fortunately, most of them begin with a gerunded verb.  These are
# the ones that don't.
my %is_proc_info = (
   'After create'                 => 1,
   'Execution of init_command'    => 1,
   'FULLTEXT initialization'      => 1,
   'Reopen tables'                => 1,
   'Repair done'                  => 1,
   'Repair with keycache'         => 1,
   'System lock'                  => 1,
   'Table lock'                   => 1,
   'Thread initialized'           => 1,
   'User lock'                    => 1,
   'copy to tmp table'            => 1,
   'discard_or_import_tablespace' => 1,
   'end'                          => 1,
   'got handler lock'             => 1,
   'got old table'                => 1,
   'init'                         => 1,
   'key cache'                    => 1,
   'locks'                        => 1,
   'malloc'                       => 1,
   'query end'                    => 1,
   'rename result table'          => 1,
   'rename'                       => 1,
   'setup'                        => 1,
   'statistics'                   => 1,
   'status'                       => 1,
   'table cache'                  => 1,
   'update'                       => 1,
);

sub new {
   bless {}, shift;
}

# Parse the status and return it.
# See srv_printf_innodb_monitor in innobase/srv/srv0srv.c
# Pass in the text to parse, whether to be in debugging mode, which sections
# to parse (hashref; if empty, parse all), and whether to parse full info from
# locks and such (probably shouldn't unless you need to).
sub parse_status_text {
   my ( $self, $fulltext, $debug, $sections, $full ) = @_;

   die "I can't parse undef" unless defined $fulltext;
   $fulltext =~ s/[\r\n]+/\n/g;

   $sections ||= {};
   die '$sections must be a hashref' unless ref($sections) eq 'HASH';

   my %innodb_data = (
      got_all   => 0,         # Whether I was able to get the whole thing
      ts        => '',        # Timestamp the server put on it
      last_secs => 0,         # Num seconds the averages are over
      sections  => {},        # Parsed values from each section
   );

   if ( $debug ) {
      $innodb_data{'fulltext'} = $fulltext;
   }

   # Get the most basic info about the status: beginning and end, and whether
   # I got the whole thing (if there has been a big deadlock and there are
   # too many locks to print, the output might be truncated)
   my ( $time_text ) = $fulltext =~ m/^$s INNODB MONITOR OUTPUT$/m;
   $innodb_data{'ts'} = [ parse_innodb_timestamp( $time_text ) ];
   $innodb_data{'timestring'} = ts_to_string($innodb_data{'ts'});
   ( $innodb_data{'last_secs'} ) = $fulltext
      =~ m/Per second averages calculated from the last $d seconds/;

   ( my $got_all ) = $fulltext =~ m/END OF INNODB MONITOR OUTPUT/;
   $innodb_data{'got_all'} = $got_all || 0;

   # Split it into sections.  Each section begins with
   # -----
   # LABEL
   # -----
   my %innodb_sections;
   my @matches = $fulltext
      =~ m#\n(---+)\n([A-Z /]+)\n\1\n(.*?)(?=\n(---+)\n[A-Z /]+\n\4\n|$)#gs;
   while ( my ( $start, $name, $text, $end ) = splice(@matches, 0, 4) ) {
      $innodb_sections{$name} = [ $text, $end ? 1 : 0 ];
   }
   # The Row Operations section is a special case, because instead of ending
   # with the beginning of another section, it ends with the end of the file.
   # So this section is complete if the entire file is complete.
   $innodb_sections{'ROW OPERATIONS'}->[1] ||= $innodb_data{'got_all'};

   # Just for sanity's sake, make sure I understand what to do with each
   # section
   eval {
      foreach my $section ( keys %innodb_sections ) {
         my $header = $innodb_section_headers{$section};
         die "Unknown section $section in $fulltext\n"
            unless $header;
         $innodb_data{'sections'}->{ $header }
            ->{'fulltext'} = $innodb_sections{$section}->[0];
         $innodb_data{'sections'}->{ $header }
            ->{'complete'} = $innodb_sections{$section}->[1];
      }
   };
   if ( $EVAL_ERROR ) {
      _debug( $debug, $EVAL_ERROR);
   }

   # ################################################################
   # Parse the detailed data out of the sections.
   # ################################################################
   eval {
      foreach my $section ( keys %parser_for ) {
         if ( defined $innodb_data{'sections'}->{$section}
               && (!%$sections || (defined($sections->{$section} && $sections->{$section})) )) {
            $parser_for{$section}->(
                  $innodb_data{'sections'}->{$section},
                  $innodb_data{'sections'}->{$section}->{'complete'},
                  $debug,
                  $full )
               or delete $innodb_data{'sections'}->{$section};
         }
         else {
            delete $innodb_data{'sections'}->{$section};
         }
      }
   };
   if ( $EVAL_ERROR ) {
      _debug( $debug, $EVAL_ERROR);
   }

   return \%innodb_data;
}

# Parses the status text and returns it flattened out as a single hash.
sub get_status_hash {
   my ( $self, $fulltext, $debug, $sections, $full ) = @_;

   # Parse the status text...
   my $innodb_status
      = $self->parse_status_text($fulltext, $debug, $sections, $full );

   # Flatten the hierarchical structure into a single list by grabbing desired
   # sections from it.
   return
      (map { 'IB_' . $_ => $innodb_status->{$_} } qw(timestring last_secs got_all)),
      (map { 'IB_bp_' . $_ => $innodb_status->{'sections'}->{'bp'}->{$_} }
         qw( writes_pending buf_pool_hit_rate total_mem_alloc buf_pool_reads
            awe_mem_alloc pages_modified writes_pending_lru page_creates_sec
            reads_pending pages_total buf_pool_hits writes_pending_single_page
            page_writes_sec pages_read pages_written page_reads_sec
            writes_pending_flush_list buf_pool_size add_pool_alloc
            dict_mem_alloc pages_created buf_free complete )),
      (map { 'IB_tx_' . $_ => $innodb_status->{'sections'}->{'tx'}->{$_} }
         qw( num_lock_structs history_list_len purge_done_for transactions
            purge_undo_for is_truncated trx_id_counter complete )),
      (map { 'IB_ib_' . $_ => $innodb_status->{'sections'}->{'ib'}->{$_} }
         qw( hash_table_size hash_searches_s non_hash_searches_s
            bufs_in_node_heap used_cells size free_list_len seg_size inserts
            merged_recs merges complete )),
      (map { 'IB_lg_' . $_ => $innodb_status->{'sections'}->{'lg'}->{$_} }
         qw( log_ios_done pending_chkp_writes last_chkp log_ios_s
            log_flushed_to log_seq_no pending_log_writes complete )),
      (map { 'IB_sm_' . $_ => $innodb_status->{'sections'}->{'sm'}->{$_} }
         qw( wait_array_size rw_shared_spins rw_excl_os_waits mutex_os_waits
            mutex_spin_rounds mutex_spin_waits rw_excl_spins rw_shared_os_waits
            waits signal_count reservation_count complete )),
      (map { 'IB_ro_' . $_ => $innodb_status->{'sections'}->{'ro'}->{$_} }
         qw( queries_in_queue n_reserved_extents main_thread_state
         main_thread_proc_no main_thread_id read_sec del_sec upd_sec ins_sec
         read_views_open num_rows_upd num_rows_ins num_rows_read
         queries_inside num_rows_del complete )),
      (map { 'IB_fk_' . $_ => $innodb_status->{'sections'}->{'fk'}->{$_} }
         qw( trigger parent_table child_index parent_index attempted_op
         child_db timestring fk_name records col_name reason txn parent_db
         type child_table parent_col complete )),
      (map { 'IB_io_' . $_ => $innodb_status->{'sections'}->{'io'}->{$_} }
         qw( pending_buffer_pool_flushes pending_pwrites pending_preads
         pending_normal_aio_reads fsyncs_s os_file_writes pending_sync_ios
         reads_s flush_type avg_bytes_s pending_ibuf_aio_reads writes_s
         threads os_file_reads pending_aio_writes pending_log_ios os_fsyncs
         pending_log_flushes complete )),
      (map { 'IB_dl_' . $_ => $innodb_status->{'sections'}->{'dl'}->{$_} }
         qw( timestring rolled_back txns complete ));

}

sub ts_to_string {
   my $parts = shift;
   return sprintf('%02d-%02d-%02d %02d:%02d:%02d', @$parts);
}

sub parse_innodb_timestamp {
   my $text = shift;
   my ( $y, $m, $d, $h, $i, $s )
      = $text =~ m/^(\d\d)(\d\d)(\d\d) +(\d+):(\d+):(\d+)$/;
   die("Can't get timestamp from $text\n") unless $y;
   $y += 2000;
   return ( $y, $m, $d, $h, $i, $s );
}

sub parse_fk_section {
   my ( $section, $complete, $debug, $full ) = @_;
   my $fulltext = $section->{'fulltext'};

   return 0 unless $fulltext;

   my ( $ts, $type ) = $fulltext =~ m/^$s\s+(\w+)/m;
   $section->{'ts'} = [ parse_innodb_timestamp( $ts ) ];
   $section->{'timestring'} = ts_to_string($section->{'ts'});
   $section->{'type'} = $type;

   # Decide which type of FK error happened, and dispatch to the right parser.
   if ( $type && $fk_parser_for{$type} ) {
      $fk_parser_for{$type}->( $section, $complete, $debug, $fulltext, $full );
   }

   delete $section->{'fulltext'} unless $debug;

   return 1;
}

sub parse_fk_cant_drop_parent_error {
   my ( $section, $complete, $debug, $fulltext, $full ) = @_;

   # Parse the parent/child table info out
   @{$section}{ qw(attempted_op parent_db parent_table) } = $fulltext
      =~ m{Cannot $w table `(.*)/(.*)`}m;
   @{$section}{ qw(child_db child_table) } = $fulltext
      =~ m{because it is referenced by `(.*)/(.*)`}m;

   ( $section->{'reason'} ) = $fulltext =~ m/(Cannot .*)/s;
   $section->{'reason'} =~ s/\n(?:InnoDB: )?/ /gm
      if $section->{'reason'};

   # Certain data may not be present.  Make them '' if not present.
   map { $section->{$_} ||= "" }
      qw(child_index fk_name col_name parent_col);
}

# See dict/dict0dict.c, function dict_foreign_error_report
# I don't care much about these.  There are lots of different messages, and
# they come from someone trying to create a foreign key, or similar
# statements.  They aren't indicative of some transaction trying to insert,
# delete or update data.  Sometimes it is possible to parse out a lot of
# information about the tables and indexes involved, but often the message
# contains the DDL string the user entered, which is way too much for this
# module to try to handle.
sub parse_fk_bad_constraint_error {
   my ( $section, $complete, $debug, $fulltext, $full ) = @_;

   # Parse the parent/child table and index info out
   @{$section}{ qw(child_db child_table) } = $fulltext
      =~ m{Error in foreign key constraint of table (.*)/(.*):$}m;
   $section->{'attempted_op'} = 'DDL';

   # FK name, parent info... if possible.
   @{$section}{ qw(fk_name col_name parent_db parent_table parent_col) }
      = $fulltext
      =~ m/CONSTRAINT `?$n`? FOREIGN KEY \(`?$n`?\) REFERENCES (?:`?$n`?\.)?`?$n`? \(`?$n`?\)/;

   if ( !defined($section->{'fk_name'}) ) {
      # Try to parse SQL a user might have typed in a CREATE statement or such
      @{$section}{ qw(col_name parent_db parent_table parent_col) }
         = $fulltext
         =~ m/FOREIGN\s+KEY\s*\(`?$n`?\)\s+REFERENCES\s+(?:`?$n`?\.)?`?$n`?\s*\(`?$n`?\)/i;
   }
   $section->{'parent_db'} ||= $section->{'child_db'};

   # Name of the child index (index in the same table where the FK is, see
   # definition of dict_foreign_struct in include/dict0mem.h, where it is
   # called foreign_index, as opposed to referenced_index which is in the
   # parent table.  This may not be possible to find.
   @{$section}{ qw(child_index) } = $fulltext
      =~ m/^The index in the foreign key in table is $n$/m;

   @{$section}{ qw(reason) } = $fulltext =~ m/:\s*([^:]+)(?= Constraint:|$)/ms;
   $section->{'reason'} =~ s/\s+/ /g
      if $section->{'reason'};
   
   # Certain data may not be present.  Make them '' if not present.
   map { $section->{$_} ||= "" }
      qw(child_index fk_name col_name parent_table parent_col);
}

# see source file row/row0ins.c
sub parse_fk_transaction_error {
   my ( $section, $complete, $debug, $fulltext, $full ) = @_;

   # Parse the txn info out
   my ( $txn ) = $fulltext
      =~ m/Transaction:\n(TRANSACTION.*)\nForeign key constraint fails/s;
   if ( $txn ) {
      $section->{'txn'} = parse_tx_text( $txn, $complete, $debug, $full );
   }

   # Parse the parent/child table and index info out.  There are two types: an
   # update or a delete of a parent record leaves a child orphaned
   # (row_ins_foreign_report_err), and an insert or update of a child record has
   # no matching parent record (row_ins_foreign_report_add_err).

   @{$section}{ qw(reason child_db child_table) }
      = $fulltext =~ m{^(Foreign key constraint fails for table `(.*)/(.*)`:)$}m;

   @{$section}{ qw(fk_name col_name parent_db parent_table parent_col) }
      = $fulltext
      =~ m/CONSTRAINT `$n` FOREIGN KEY \(`$n`\) REFERENCES (?:`$n`\.)?`$n` \(`$n`\)/;
   $section->{'parent_db'} ||= $section->{'child_db'};

   # Special case, which I don't know how to trigger, but see
   # innobase/row/row0ins.c row_ins_check_foreign_constraint
   if ( $fulltext =~ m/ibd file does not currently exist!/ ) {
      my ( $attempted_op, $index, $records )
         = $fulltext =~ m/^Trying to (add to index) `$n` tuple:\n(.*))?/sm;
      $section->{'child_index'} = $index;
      $section->{'attempted_op'} = $attempted_op || '';
      if ( $records && $full ) {
         ( $section->{'records'} )
            = parse_innodb_record_dump( $records, $complete, $debug );
      }
      @{$section}{qw(parent_db parent_table)}
         =~ m/^But the parent table `$n`\.`$n`$/m;
   }
   else {
      my ( $attempted_op, $which, $index )
         = $fulltext =~ m/^Trying to ([\w ]*) in (child|parent) table, in index `$n` tuple:$/m;
      if ( $which ) {
         $section->{$which . '_index'} = $index;
         $section->{'attempted_op'} = $attempted_op || '';

         # Parse out the related records in the other table.
         my ( $search_index, $records );
         if ( $which eq 'child' ) {
            ( $search_index, $records ) = $fulltext
               =~ m/^But in parent table [^,]*, in index `$n`,\nthe closest match we can find is record:\n(.*)/ms;
            $section->{'parent_index'} = $search_index;
         }
         else {
            ( $search_index, $records ) = $fulltext
               =~ m/^But in child table [^,]*, in index `$n`, (?:the record is not available|there is a record:\n(.*))?/ms;
            $section->{'child_index'} = $search_index;
         }
         if ( $records && $full ) {
            $section->{'records'}
               = parse_innodb_record_dump( $records, $complete, $debug );
         }
         else {
            $section->{'records'} = '';
         }
      }
   }

   # Parse out the tuple trying to be updated, deleted or inserted.
   my ( $trigger ) = $fulltext =~ m/^(DATA TUPLE: \d+ fields;\n.*)$/m;
   if ( $trigger ) {
      $section->{'trigger'} = parse_innodb_record_dump( $trigger, $complete, $debug );
   }

   # Certain data may not be present.  Make them '' if not present.
   map { $section->{$_} ||= "" }
      qw(child_index fk_name col_name parent_table parent_col);
}

# There are new-style and old-style record formats.  See rem/rem0rec.c
# TODO: write some tests for this
sub parse_innodb_record_dump {
   my ( $dump, $complete, $debug ) = @_;
   return undef unless $dump;

   my $result = {};

   if ( $dump =~ m/PHYSICAL RECORD/ ) {
      my $style = $dump =~ m/compact format/ ? 'new' : 'old';
      $result->{'style'} = $style;

      # This is a new-style record.
      if ( $style eq 'new' ) {
         @{$result}{qw( heap_no type num_fields info_bits )}
            = $dump
            =~ m/^(?:Record lock, heap no $d )?([A-Z ]+): n_fields $d; compact format; info bits $d$/m;
      }

      # OK, it's old-style.  Unfortunately there are variations here too.
      elsif ( $dump =~ m/-byte offs / ) {
         # Older-old style.
         @{$result}{qw( heap_no type num_fields byte_offset info_bits )}
            = $dump
            =~ m/^(?:Record lock, heap no $d )?([A-Z ]+): n_fields $d; $d-byte offs [A-Z]+; info bits $d$/m;
            if ( $dump !~ m/-byte offs TRUE/ ) {
               $result->{'byte_offset'} = 0;
            }
      }
      else {
         # Newer-old style.
         @{$result}{qw( heap_no type num_fields byte_offset info_bits )}
            = $dump
            =~ m/^(?:Record lock, heap no $d )?([A-Z ]+): n_fields $d; $d-byte offsets; info bits $d$/m;
      }

   }
   else {
      $result->{'style'} = 'tuple';
      @{$result}{qw( type num_fields )}
         = $dump =~ m/^(DATA TUPLE): $d fields;$/m;
   }

   # Fill in default values for things that couldn't be parsed.
   map { $result->{$_} ||= 0 }
      qw(heap_no num_fields byte_offset info_bits);
   map { $result->{$_} ||= '' }
      qw(style type );

   my @fields = $dump =~ m/ (\d+:.*?;?);(?=$| \d+:)/gm;
   $result->{'fields'} = [ map { parse_field($_, $complete, $debug ) } @fields ];

   return $result;
}

# New/old-style applies here.  See rem/rem0rec.c
# $text should not include the leading space or the second trailing semicolon.
sub parse_field {
   my ( $text, $complete, $debug ) = @_;

   # Sample fields:
   # '4: SQL NULL, size 4 '
   # '1: len 6; hex 000000005601; asc     V ;'
   # '6: SQL NULL'
   # '5: len 30; hex 687474703a2f2f7777772e737765657477617465722e636f6d2f73746f72; asc http://www.sweetwater.com/stor;...(truncated)'
   my ( $id, $nullsize, $len, $hex, $asc, $truncated );
   ( $id, $nullsize ) = $text =~ m/^$d: SQL NULL, size $d $/;
   if ( !defined($id) ) {
      ( $id ) = $text =~ m/^$d: SQL NULL$/;
   }
   if ( !defined($id) ) {
      ( $id, $len, $hex, $asc, $truncated )
         = $text =~ m/^$d: len $d; hex $h; asc (.*);(\.\.\.\(truncated\))?$/;
   }

   die "Could not parse this field: '$text'" unless defined $id;
   return {
      id    => $id,
      len   => defined($len) ? $len : defined($nullsize) ? $nullsize : 0,
      'hex' => defined($hex) ? $hex : '',
      asc   => defined($asc) ? $asc : '',
      trunc => $truncated ? 1 : 0,
   };

}

sub parse_dl_section {
   my ( $dl, $complete, $debug, $full ) = @_;
   return unless $dl;
   my $fulltext = $dl->{'fulltext'};
   return 0 unless $fulltext;

   my ( $ts ) = $fulltext =~ m/^$s$/m;
   return 0 unless $ts;

   $dl->{'ts'} = [ parse_innodb_timestamp( $ts ) ];
   $dl->{'timestring'} = ts_to_string($dl->{'ts'});
   $dl->{'txns'} = {};

   my @sections
      = $fulltext
      =~ m{
         ^\*{3}\s([^\n]*)  # *** (1) WAITING FOR THIS...
         (.*?)             # Followed by anything, non-greedy
         (?=(?:^\*{3})|\z) # Followed by another three stars or EOF
      }gmsx;


   # Loop through each section.  There are no assumptions about how many
   # there are, who holds and wants what locks, and who gets rolled back.
   while ( my ($header, $body) = splice(@sections, 0, 2) ) {
      my ( $txn_id, $what ) = $header =~ m/^\($d\) (.*):$/;
      next unless $txn_id;
      $dl->{'txns'}->{$txn_id} ||= {};
      my $txn = $dl->{'txns'}->{$txn_id};

      if ( $what eq 'TRANSACTION' ) {
         $txn->{'tx'} = parse_tx_text( $body, $complete, $debug, $full );
      }
      else {
         push @{$txn->{'locks'}}, parse_innodb_record_locks( $body, $complete, $debug, $full );
      }
   }

   @{ $dl }{ qw(rolled_back) }
      = $fulltext =~ m/^\*\*\* WE ROLL BACK TRANSACTION \($d\)$/m;

   # Make sure certain values aren't undef
   map { $dl->{$_} ||= '' } qw(rolled_back);

   delete $dl->{'fulltext'} unless $debug;
   return 1;
}

sub parse_innodb_record_locks {
   my ( $text, $complete, $debug, $full ) = @_;
   my @result;

   foreach my $lock ( $text =~ m/(^(?:RECORD|TABLE) LOCKS?.*$)/gm ) {
      my $hash = {};
      @{$hash}{ qw(lock_type space_id page_no n_bits index db table txn_id lock_mode) }
         = $lock
         =~ m{^(RECORD|TABLE) LOCKS? (?:space id $d page no $d n bits $d index `?$n`? of )?table `$n(?:/|`\.`)$n` trx id $t lock.mode (\S+)}m;
      ( $hash->{'special'} )
         = $lock =~ m/^(?:RECORD|TABLE) .*? locks (rec but not gap|gap before rec)/m;
      $hash->{'insert_intention'}
         = $lock =~ m/^(?:RECORD|TABLE) .*? insert intention/m ? 1 : 0;
      $hash->{'waiting'}
         = $lock =~ m/^(?:RECORD|TABLE) .*? waiting/m ? 1 : 0;

      # Some things may not be in the text, so make sure they are not
      # undef.
      map { $hash->{$_} ||= 0 } qw(n_bits page_no space_id);
      map { $hash->{$_} ||= "" } qw(index special);
      push @result, $hash;
   }

   return @result;
}

sub parse_tx_text {
   my ( $txn, $complete, $debug, $full ) = @_;

   my ( $txn_id, $txn_status, $active_secs, $proc_no, $os_thread_id )
      = $txn
      =~ m/^(?:---)?TRANSACTION $t, (\D*?)(?: $d sec)?, (?:process no $d, )?OS thread id $d/m;
   my ( $thread_status, $thread_decl_inside )
      = $txn
      =~ m/OS thread id \d+(?: ([^,]+?))?(?:, thread declared inside InnoDB $d)?$/m;

   # Parsing the line that begins 'MySQL thread id' is complicated.  The only
   # thing always in the line is the thread and query id.  See function
   # innobase_mysql_print_thd in InnoDB source file sql/ha_innodb.cc.
   my ( $thread_line ) = $txn =~ m/^(MySQL thread id .*)$/m;
   my ( $mysql_thread_id, $query_id, $hostname, $ip, $user, $query_status );

   if ( $thread_line ) {
      # These parts can always be gotten.
      ( $mysql_thread_id, $query_id ) = $thread_line =~ m/^MySQL thread id $d, query id $d/m;

      # If it's a master/slave thread, "Has (read|sent) all" may be the thread's
      # proc_info.  In these cases, there won't be any host/ip/user info
      ( $query_status ) = $thread_line =~ m/(Has (?:read|sent) all .*$)/m;
      if ( defined($query_status) ) {
         $user = 'system user';
      }

      # It may be the case that the query id is the last thing in the line.
      elsif ( $thread_line =~ m/query id \d+ / ) {
         # The IP address is the only non-word thing left, so it's the most
         # useful marker for where I have to start guessing.
         ( $hostname, $ip ) = $thread_line =~ m/query id \d+(?: ([A-Za-z]\S+))? $i/m;
         if ( defined $ip ) {
            ( $user, $query_status ) = $thread_line =~ m/$ip $w(?: (.*))?$/;
         }
         else { # OK, there wasn't an IP address.
            # There might not be ANYTHING except the query status.
            ( $query_status ) = $thread_line =~ m/query id \d+ (.*)$/;
            if ( $query_status !~ m/^\w+ing/ && !exists($is_proc_info{$query_status}) ) {
               # The remaining tokens are, in order: hostname, user, query_status.
               # It's basically impossible to know which is which.
               ( $hostname, $user, $query_status ) = $thread_line
                  =~ m/query id \d+(?: ([A-Za-z]\S+))?(?: $w(?: (.*))?)?$/m;
            }
            else {
               $user = 'system user';
            }
         }
      }
   }

   my ( $lock_wait_status, $lock_structs, $heap_size, $row_locks, $undo_log_entries )
      = $txn
      =~ m/^(?:(\D*) )?$d lock struct\(s\), heap size $d(?:, $d row lock\(s\))?(?:, undo log entries $d)?$/m;
   my ( $lock_wait_time )
      = $txn
      =~ m/^------- TRX HAS BEEN WAITING $d SEC/m;

   my $locks;
   # If the transaction has locks, grab the locks.
   if ( $txn =~ m/^TABLE LOCK|RECORD LOCKS/ ) {
      $locks = [parse_innodb_record_locks($txn, $complete, $debug, $full)];
   }
   
   my ( $tables_in_use, $tables_locked )
      = $txn
      =~ m/^mysql tables in use $d, locked $d$/m;
   my ( $txn_doesnt_see_ge, $txn_sees_lt )
      = $txn
      =~ m/^Trx read view will not see trx with id >= $t, sees < $t$/m;
   my $has_read_view = defined($txn_doesnt_see_ge);
   # Only a certain number of bytes of the query text are included here, at least
   # under some circumstances.  Some versions include 300, some 600.
   my ( $query_text )
      = $txn
      =~ m{
         ^MySQL\sthread\sid\s[^\n]+\n           # This comes before the query text
         (.*?)                                  # The query text
         (?=                                    # Followed by any of...
            ^Trx\sread\sview
            |^-------\sTRX\sHAS\sBEEN\sWAITING
            |^TABLE\sLOCK
            |^RECORD\sLOCKS\sspace\sid
            |^(?:---)?TRANSACTION
            |^\*\*\*\s\(\d\)
            |\Z
         )
      }xms;
   if ( $query_text ) {
      $query_text =~ s/\s+$//;
   }
   else {
      $query_text = '';
   }

   my %stuff = (
      active_secs        => $active_secs,
      has_read_view      => $has_read_view,
      heap_size          => $heap_size,
      hostname           => $hostname,
      ip                 => $ip,
      lock_structs       => $lock_structs,
      lock_wait_status   => $lock_wait_status,
      lock_wait_time     => $lock_wait_time,
      mysql_thread_id    => $mysql_thread_id,
      os_thread_id       => $os_thread_id,
      proc_no            => $proc_no,
      query_id           => $query_id,
      query_status       => $query_status,
      query_text         => $query_text,
      row_locks          => $row_locks,
      tables_in_use      => $tables_in_use,
      tables_locked      => $tables_locked,
      thread_decl_inside => $thread_decl_inside,
      thread_status      => $thread_status,
      txn_doesnt_see_ge  => $txn_doesnt_see_ge,
      txn_id             => $txn_id,
      txn_sees_lt        => $txn_sees_lt,
      txn_status         => $txn_status,
      undo_log_entries   => $undo_log_entries,
      user               => $user,
   );
   $stuff{'fulltext'} = $txn if $debug;
   $stuff{'locks'} = $locks if $locks;

   # Some things may not be in the txn text, so make sure they are not
   # undef.
   map { $stuff{$_} ||= 0 } qw(active_secs heap_size lock_structs
         tables_in_use undo_log_entries tables_locked has_read_view
         thread_decl_inside lock_wait_time proc_no row_locks);
   map { $stuff{$_} ||= "" } qw(thread_status txn_doesnt_see_ge
         txn_sees_lt query_status ip query_text lock_wait_status user);
   $stuff{'hostname'} ||= $stuff{'ip'};

   return \%stuff;
}

sub parse_tx_section {
   my ( $section, $complete, $debug, $full ) = @_;
   return unless $section && $section->{'fulltext'};
   my $fulltext = $section->{'fulltext'};
   $section->{'transactions'} = [];

   # Handle the individual transactions
   my @transactions = $fulltext =~ m/(---TRANSACTION \d.*?)(?=\n---TRANSACTION|$)/gs;
   foreach my $txn ( @transactions ) {
      my $stuff = parse_tx_text( $txn, $complete, $debug, $full );
      delete $stuff->{'fulltext'} unless $debug;
      push @{$section->{'transactions'}}, $stuff;
   }

   # Handle the general info
   @{$section}{ 'trx_id_counter' }
      = $fulltext =~ m/^Trx id counter $t$/m;
   @{$section}{ 'purge_done_for', 'purge_undo_for' }
      = $fulltext =~ m/^Purge done for trx's n:o < $t undo n:o < $t$/m;
   @{$section}{ 'history_list_len' } # This isn't present in some 4.x versions
      = $fulltext =~ m/^History list length $d$/m;
   @{$section}{ 'num_lock_structs' }
      = $fulltext =~ m/^Total number of lock structs in row lock hash table $d$/m;
   @{$section}{ 'is_truncated' }
      = $fulltext =~ m/^\.\.\. truncated\.\.\.$/m ? 1 : 0;

   # Fill in things that might not be present
   foreach ( qw(history_list_len) ) {
      $section->{$_} ||= 0;
   }

   delete $section->{'fulltext'} unless $debug;
   return 1;
}

# I've read the source for this section.
sub parse_ro_section {
   my ( $section, $complete, $debug, $full ) = @_;
   return unless $section && $section->{'fulltext'};
   my $fulltext = $section->{'fulltext'};

   # Grab the info
   @{$section}{ 'queries_inside', 'queries_in_queue' }
      = $fulltext =~ m/^$d queries inside InnoDB, $d queries in queue$/m;
   ( $section->{ 'read_views_open' } )
      = $fulltext =~ m/^$d read views open inside InnoDB$/m;
   ( $section->{ 'n_reserved_extents' } )
      = $fulltext =~ m/^$d tablespace extents now reserved for B-tree/m;
   @{$section}{ 'main_thread_proc_no', 'main_thread_id', 'main_thread_state' }
      = $fulltext =~ m/^Main thread (?:process no. $d, )?id $d, state: (.*)$/m;
   @{$section}{ 'num_rows_ins', 'num_rows_upd', 'num_rows_del', 'num_rows_read' }
      = $fulltext =~ m/^Number of rows inserted $d, updated $d, deleted $d, read $d$/m;
   @{$section}{ 'ins_sec', 'upd_sec', 'del_sec', 'read_sec' }
      = $fulltext =~ m#^$f inserts/s, $f updates/s, $f deletes/s, $f reads/s$#m;
   $section->{'main_thread_proc_no'} ||= 0;

   map { $section->{$_} ||= 0 } qw(read_views_open n_reserved_extents);
   delete $section->{'fulltext'} unless $debug;
   return 1;
}

sub parse_lg_section {
   my ( $section, $complete, $debug, $full ) = @_;
   return unless $section;
   my $fulltext = $section->{'fulltext'};

   # Grab the info
   ( $section->{ 'log_seq_no' } )
      = $fulltext =~ m/Log sequence number \s*(\d.*)$/m;
   ( $section->{ 'log_flushed_to' } )
      = $fulltext =~ m/Log flushed up to \s*(\d.*)$/m;
   ( $section->{ 'last_chkp' } )
      = $fulltext =~ m/Last checkpoint at \s*(\d.*)$/m;
   @{$section}{ 'pending_log_writes', 'pending_chkp_writes' }
      = $fulltext =~ m/$d pending log writes, $d pending chkp writes/;
   @{$section}{ 'log_ios_done', 'log_ios_s' }
      = $fulltext =~ m#$d log i/o's done, $f log i/o's/second#;

   delete $section->{'fulltext'} unless $debug;
   return 1;
}

sub parse_ib_section {
   my ( $section, $complete, $debug, $full ) = @_;
   return unless $section && $section->{'fulltext'};
   my $fulltext = $section->{'fulltext'};

   # Some servers will output ibuf information for tablespace 0, as though there
   # might be many tablespaces with insert buffers.  (In practice I believe
   # the source code shows there will only ever be one).  I have to parse both
   # cases here, but I assume there will only be one.
   @{$section}{ 'size', 'free_list_len', 'seg_size' }
      = $fulltext =~ m/^Ibuf(?: for space 0)?: size $d, free list len $d, seg size $d,$/m;
   @{$section}{ 'inserts', 'merged_recs', 'merges' }
      = $fulltext =~ m/^$d inserts, $d merged recs, $d merges$/m;

   @{$section}{ 'hash_table_size', 'used_cells', 'bufs_in_node_heap' }
      = $fulltext =~ m/^Hash table size $d, used cells $d, node heap has $d buffer\(s\)$/m;
   @{$section}{ 'hash_searches_s', 'non_hash_searches_s' }
      = $fulltext =~ m{^$f hash searches/s, $f non-hash searches/s$}m;

   delete $section->{'fulltext'} unless $debug;
   return 1;
}

sub parse_wait_array {
   my ( $text, $complete, $debug, $full ) = @_;
   my %result;

   @result{ qw(thread waited_at_filename waited_at_line waited_secs) }
      = $text =~ m/^--Thread $d has waited at $fl for $f seconds/m;

   # Depending on whether it's a SYNC_MUTEX,RW_LOCK_EX,RW_LOCK_SHARED,
   # there will be different text output
   if ( $text =~ m/^Mutex at/m ) {
      $result{'request_type'} = 'M';
      @result{ qw( lock_mem_addr lock_cfile_name lock_cline lock_var) }
         = $text =~ m/^Mutex at $h created file $fl, lock var $d$/m;
      @result{ qw( waiters_flag )}
         = $text =~ m/^waiters flag $d$/m;
   }
   else {
      @result{ qw( request_type lock_mem_addr lock_cfile_name lock_cline) }
         = $text =~ m/^(.)-lock on RW-latch at $h created in file $fl$/m;
      @result{ qw( writer_thread writer_lock_mode ) }
         = $text =~ m/^a writer \(thread id $d\) has reserved it in mode  (.*)$/m;
      @result{ qw( num_readers waiters_flag )}
         = $text =~ m/^number of readers $d, waiters flag $d$/m;
      @result{ qw(last_s_file_name last_s_line ) }
         = $text =~ m/Last time read locked in file $fl$/m;
      @result{ qw(last_x_file_name last_x_line ) }
         = $text =~ m/Last time write locked in file $fl$/m;
   }

   $result{'cell_waiting'} = $text =~ m/^wait has ended$/m ? 0 : 1;
   $result{'cell_event_set'} = $text =~ m/^wait is ending$/m ? 1 : 0;

   # Because there are two code paths, some things won't get set.
   map { $result{$_} ||= '' }
      qw(last_s_file_name last_x_file_name writer_lock_mode);
   map { $result{$_} ||= 0 }
      qw(num_readers lock_var last_s_line last_x_line writer_thread);

   return \%result;
}

sub parse_sm_section {
   my ( $section, $complete, $debug, $full ) = @_;
   return 0 unless $section && $section->{'fulltext'};
   my $fulltext = $section->{'fulltext'};

   # Grab the info
   @{$section}{ 'reservation_count', 'signal_count' }
      = $fulltext =~ m/^OS WAIT ARRAY INFO: reservation count $d, signal count $d$/m;
   @{$section}{ 'mutex_spin_waits', 'mutex_spin_rounds', 'mutex_os_waits' }
      = $fulltext =~ m/^Mutex spin waits $d, rounds $d, OS waits $d$/m;
   @{$section}{ 'rw_shared_spins', 'rw_shared_os_waits', 'rw_excl_spins', 'rw_excl_os_waits' }
      = $fulltext =~ m/^RW-shared spins $d, OS waits $d; RW-excl spins $d, OS waits $d$/m;

   # Look for info on waits.
   my @waits = $fulltext =~ m/^(--Thread.*?)^(?=Mutex spin|--Thread)/gms;
   $section->{'waits'} = [ map { parse_wait_array($_, $complete, $debug) } @waits ];
   $section->{'wait_array_size'} = scalar(@waits);

   delete $section->{'fulltext'} unless $debug;
   return 1;
}

# I've read the source for this section.
sub parse_bp_section {
   my ( $section, $complete, $debug, $full ) = @_;
   return unless $section && $section->{'fulltext'};
   my $fulltext = $section->{'fulltext'};

   # Grab the info
   @{$section}{ 'total_mem_alloc', 'add_pool_alloc' }
      = $fulltext =~ m/^Total memory allocated $d; in additional pool allocated $d$/m;
   @{$section}{'dict_mem_alloc'}     = $fulltext =~ m/Dictionary memory allocated $d/;
   @{$section}{'awe_mem_alloc'}      = $fulltext =~ m/$d MB of AWE memory/;
   @{$section}{'buf_pool_size'}      = $fulltext =~ m/^Buffer pool size\s*$d$/m;
   @{$section}{'buf_free'}           = $fulltext =~ m/^Free buffers\s*$d$/m;
   @{$section}{'pages_total'}        = $fulltext =~ m/^Database pages\s*$d$/m;
   @{$section}{'pages_modified'}     = $fulltext =~ m/^Modified db pages\s*$d$/m;
   @{$section}{'pages_read', 'pages_created', 'pages_written'}
      = $fulltext =~ m/^Pages read $d, created $d, written $d$/m;
   @{$section}{'page_reads_sec', 'page_creates_sec', 'page_writes_sec'}
      = $fulltext =~ m{^$f reads/s, $f creates/s, $f writes/s$}m;
   @{$section}{'buf_pool_hits', 'buf_pool_reads'}
      = $fulltext =~ m{Buffer pool hit rate $d / $d$}m;
   if ($fulltext =~ m/^No buffer pool page gets since the last printout$/m) {
      @{$section}{'buf_pool_hits', 'buf_pool_reads'} = (0, 0);
      @{$section}{'buf_pool_hit_rate'} = '--';
   }
   else {
      @{$section}{'buf_pool_hit_rate'}
         = $fulltext =~ m{Buffer pool hit rate (\d+ / \d+)$}m;
   }
   @{$section}{'reads_pending'} = $fulltext =~ m/^Pending reads $d/m;
   @{$section}{'writes_pending_lru', 'writes_pending_flush_list', 'writes_pending_single_page' }
      = $fulltext =~ m/^Pending writes: LRU $d, flush list $d, single page $d$/m;

   map { $section->{$_} ||= 0 }
      qw(writes_pending_lru writes_pending_flush_list writes_pending_single_page
      awe_mem_alloc dict_mem_alloc);
   @{$section}{'writes_pending'} = List::Util::sum(
      @{$section}{ qw(writes_pending_lru writes_pending_flush_list writes_pending_single_page) });

   delete $section->{'fulltext'} unless $debug;
   return 1;
}

# I've read the source for this.
sub parse_io_section {
   my ( $section, $complete, $debug, $full ) = @_;
   return unless $section && $section->{'fulltext'};
   my $fulltext = $section->{'fulltext'};
   $section->{'threads'} = {};

   # Grab the I/O thread info
   my @threads = $fulltext =~ m<^(I/O thread \d+ .*)$>gm;
   foreach my $thread (@threads) {
      my ( $tid, $state, $purpose, $event_set )
         = $thread =~ m{I/O thread $d state: (.+?) \((.*)\)(?: ev set)?$}m;
      if ( defined $tid ) {
         $section->{'threads'}->{$tid} = {
            thread    => $tid,
            state     => $state,
            purpose   => $purpose,
            event_set => $event_set ? 1 : 0,
         };
      }
   }

   # Grab the reads/writes/flushes info
   @{$section}{ 'pending_normal_aio_reads', 'pending_aio_writes' }
      = $fulltext =~ m/^Pending normal aio reads: $d, aio writes: $d,$/m;
   @{$section}{ 'pending_ibuf_aio_reads', 'pending_log_ios', 'pending_sync_ios' }
      = $fulltext =~ m{^ ibuf aio reads: $d, log i/o's: $d, sync i/o's: $d$}m;
   @{$section}{ 'flush_type', 'pending_log_flushes', 'pending_buffer_pool_flushes' }
      = $fulltext =~ m/^Pending flushes \($w\) log: $d; buffer pool: $d$/m;
   @{$section}{ 'os_file_reads', 'os_file_writes', 'os_fsyncs' }
      = $fulltext =~ m/^$d OS file reads, $d OS file writes, $d OS fsyncs$/m;
   @{$section}{ 'reads_s', 'avg_bytes_s', 'writes_s', 'fsyncs_s' }
      = $fulltext =~ m{^$f reads/s, $d avg bytes/read, $f writes/s, $f fsyncs/s$}m;
   @{$section}{ 'pending_preads', 'pending_pwrites' }
      = $fulltext =~ m/$d pending preads, $d pending pwrites$/m;
   @{$section}{ 'pending_preads', 'pending_pwrites' } = (0, 0)
      unless defined($section->{'pending_preads'});

   delete $section->{'fulltext'} unless $debug;
   return 1;
}

sub _debug {
   my ( $debug, $msg ) = @_;
   if ( $debug ) {
      die $msg;
   }
   else {
      warn $msg;
   }
   return 1;
}

1;

# end_of_package InnoDBParser

package main;

use sigtrap qw(handler finish untrapped normal-signals);

use Data::Dumper;
use DBI;
use English qw(-no_match_vars);
use File::Basename qw(dirname);
use File::Temp;
use Getopt::Long;
use List::Util qw(max min maxstr sum);
use POSIX qw(ceil);
use Time::HiRes qw(time sleep);
use Term::ReadKey qw(ReadMode ReadKey);

# License and warranty information. {{{1
# ###########################################################################

my $innotop_license = <<"LICENSE";

This is innotop version $VERSION, a MySQL and InnoDB monitor.

This program is copyright (c) 2006 Baron Schwartz.
Feedback and improvements are welcome.

THIS PROGRAM IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation, version 2; OR the Perl Artistic License.  On UNIX and similar
systems, you can issue `man perlgpl' or `man perlartistic' to read these
licenses.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place, Suite 330, Boston, MA  02111-1307  USA.
LICENSE

# Configuration information and global setup {{{1
# ###########################################################################

# Really, really, super-global variables.
my @config_versions = (
   "000-000-000", "001-003-000", # config file was one big name-value hash.
   "001-003-000", "001-004-002", # config file contained non-user-defined stuff.
);

my $clear_screen_sub;
my $dsn_parser = new DSNParser();

# This defines expected properties and defaults for the column definitions that
# eventually end up in tbl_meta.
my %col_props = (
   hdr     => '',
   just    => '-',
   dec     => 0,     # Whether to align the column on the decimal point
   num     => 0,
   label   => '',
   user    => 0,
   src     => '',
   tbl     => '',    # Helps when writing/reading custom columns in config files
   minw    => 0,
   maxw    => 0,
   trans   => [],
   agg     => 'first',  # Aggregate function
   aggonly => 0,        # Whether to show only when tbl_meta->{aggregate} is true
);

# Actual DBI connections to MySQL servers.
my %dbhs;

# Command-line parameters {{{2
# ###########################################################################

my @opt_spec = (
   { s => 'help',       d => 'Show this help message' },
   { s => 'color|C!',   d => 'Use terminal coloring (default)',   c => 'color' },
   { s => 'config|c=s', d => 'Config file to read' },
   { s => 'nonint|n',   d => 'Non-interactive, output tab-separated fields' },
   { s => 'count=i',    d => 'Number of updates before exiting' },
   { s => 'delay|d=f',  d => 'Delay between updates in seconds',  c => 'interval' },
   { s => 'mode|m=s',   d => 'Operating mode to start in',        c => 'mode' },
   { s => 'inc|i!',     d => 'Measure incremental differences',   c => 'status_inc' },
   { s => 'write|w',    d => 'Write running configuration into home directory if no config files were loaded' },
   { s => 'skipcentral|s',     d => 'Skip reading the central configuration file' },
   { s => 'version',    d => 'Output version information and exit' },
   { s => 'user|u=s',   d => 'User for login if not current user' },
   { s => 'password|p=s',   d => 'Password to use for connection' },
   { s => 'host|h=s',   d => 'Connect to host' },
   { s => 'port|P=i',   d => 'Port number to use for connection' },
);

# This is the container for the command-line options' values to be stored in
# after processing.  Initial values are defaults.
my %opts = (
   n => !( -t STDIN && -t STDOUT ), # If in/out aren't to terminals, we're interactive
);
# Post-process...
my %opt_seen;
foreach my $spec ( @opt_spec ) {
   my ( $long, $short ) = $spec->{s} =~ m/^(\w+)(?:\|([^!+=]*))?/;
   $spec->{k} = $short || $long;
   $spec->{l} = $long;
   $spec->{t} = $short;
   $spec->{n} = $spec->{s} =~ m/!/;
   $opts{$spec->{k}} = undef unless defined $opts{$spec->{k}};
   die "Duplicate option $spec->{k}" if $opt_seen{$spec->{k}}++;
}

Getopt::Long::Configure('no_ignore_case', 'bundling');
GetOptions( map { $_->{s} => \$opts{$_->{k}} } @opt_spec) or $opts{help} = 1;

if ( $opts{version} ) {
   print "innotop  Ver $VERSION\n";
   exit(0);
}

if ( $opts{c} and ! -f $opts{c} ) {
   print $opts{c} . " doesn't exist.  Exiting.\n";
   exit(1);
}
if ( $opts{'help'} ) {
   print "Usage: innotop <options> <innodb-status-file>\n\n";
   my $maxw = max(map { length($_->{l}) + ($_->{n} ? 4 : 0)} @opt_spec);
   foreach my $spec ( sort { $a->{l} cmp $b->{l} } @opt_spec ) {
      my $long  = $spec->{n} ? "[no]$spec->{l}" : $spec->{l};
      my $short = $spec->{t} ? "-$spec->{t}" : '';
      printf("  --%-${maxw}s %-4s %s\n", $long, $short, $spec->{d});
   }
   print <<USAGE;

innotop is a MySQL and InnoDB transaction/status monitor, like 'top' for
MySQL.  It displays queries, InnoDB transactions, lock waits, deadlocks,
foreign key errors, open tables, replication status, buffer information,
row operations, logs, I/O operations, load graph, and more.  You can
monitor many servers at once with innotop. 

USAGE
   exit(1);
}

# Meta-data (table definitions etc) {{{2
# ###########################################################################

# Expressions {{{3
# Convenience so I can copy/paste these in several places...
# ###########################################################################
my %exprs = (
   Host              => q{my $host = host || hostname || ''; ($host) = $host =~ m/^((?:[\d.]+(?=:))|(?:[a-zA-Z]\w+))/; return $host || ''},
   Port              => q{my ($p) = host =~ m/:(.*)$/; return $p || 0},
   OldVersions       => q{dulint_to_int(IB_tx_trx_id_counter) - dulint_to_int(IB_tx_purge_done_for)},
   MaxTxnTime        => q/max(map{ $_->{active_secs} } @{ IB_tx_transactions }) || 0/,
   NumTxns           => q{scalar @{ IB_tx_transactions } },
   DirtyBufs         => q{ $cur->{IB_bp_pages_modified} / ($cur->{IB_bp_buf_pool_size} || 1) },
   BufPoolFill       => q{ $cur->{IB_bp_pages_total} / ($cur->{IB_bp_buf_pool_size} || 1) },
   ServerLoad        => q{ $cur->{Threads_connected}/(Questions||1)/Uptime_hires },
   TxnTimeRemain     => q{ defined undo_log_entries && defined $pre->{undo_log_entries} && undo_log_entries < $pre->{undo_log_entries} ? undo_log_entries / (($pre->{undo_log_entries} - undo_log_entries)/((active_secs-$pre->{active_secs})||1))||1 : 0},
   SlaveCatchupRate  => ' defined $cur->{seconds_behind_master} && defined $pre->{seconds_behind_master} && $cur->{seconds_behind_master} < $pre->{seconds_behind_master} ? ($pre->{seconds_behind_master}-$cur->{seconds_behind_master})/($cur->{Uptime_hires}-$pre->{Uptime_hires}) : 0',
   QcacheHitRatio    => q{(Qcache_hits||0)/(((Com_select||0)+(Qcache_hits||0))||1)},
);

# ###########################################################################
# Column definitions {{{3
# Defines every column in every table. A named column has the following
# properties:
#    * hdr    Column header/title
#    * label  Documentation for humans.
#    * num    Whether it's numeric (for sorting).
#    * just   Alignment; generated from num, user-overridable in tbl_meta
#    * minw, maxw Auto-generated, user-overridable.
# Values from this hash are just copied to tbl_meta, which is where everything
# else in the program should read from.
# ###########################################################################

my %columns = (
   active_secs                 => { hdr => 'SecsActive',          num => 1, label => 'Seconds transaction has been active', },
   add_pool_alloc              => { hdr => 'Add\'l Pool',         num => 1, label => 'Additonal pool allocated' },
   attempted_op                => { hdr => 'Action',              num => 0, label => 'The action that caused the error' },
   awe_mem_alloc               => { hdr => 'AWE Memory',          num => 1, label => '[Windows] AWE memory allocated' },
   binlog_cache_overflow       => { hdr => 'Binlog Cache',        num => 1, label => 'Transactions too big for binlog cache that went to disk' },
   binlog_do_db                => { hdr => 'Binlog Do DB',        num => 0, label => 'binlog-do-db setting' },
   binlog_ignore_db            => { hdr => 'Binlog Ignore DB',    num => 0, label => 'binlog-ignore-db setting' },
   bps_in                      => { hdr => 'BpsIn',               num => 1, label => 'Bytes per second received by the server', },
   bps_out                     => { hdr => 'BpsOut',              num => 1, label => 'Bytes per second sent by the server', },
   buf_free                    => { hdr => 'Free Bufs',           num => 1, label => 'Buffers free in the buffer pool' },
   buf_pool_hit_rate           => { hdr => 'Hit Rate',            num => 0, label => 'Buffer pool hit rate' },
   buf_pool_hits               => { hdr => 'Hits',                num => 1, label => 'Buffer pool hits' },
   buf_pool_reads              => { hdr => 'Reads',               num => 1, label => 'Buffer pool reads' },
   buf_pool_size               => { hdr => 'Size',                num => 1, label => 'Buffer pool size' },
   bufs_in_node_heap           => { hdr => 'Node Heap Bufs',      num => 1, label => 'Buffers in buffer pool node heap' },
   bytes_behind_master         => { hdr => 'ByteLag',             num => 1, label => 'Bytes the slave lags the master in binlog' },
   cell_event_set              => { hdr => 'Ending?',             num => 1, label => 'Whether the cell event is set' },
   cell_waiting                => { hdr => 'Waiting?',            num => 1, label => 'Whether the cell is waiting' },
   child_db                    => { hdr => 'Child DB',            num => 0, label => 'The database of the child table' },
   child_index                 => { hdr => 'Child Index',         num => 0, label => 'The index in the child table' },
   child_table                 => { hdr => 'Child Table',         num => 0, label => 'The child table' },
   cmd                         => { hdr => 'Cmd',                 num => 0, label => 'Type of command being executed', },
   cnt                         => { hdr => 'Cnt',                 num => 0, label => 'Count', agg => 'count', aggonly => 1 },
   connect_retry               => { hdr => 'Connect Retry',       num => 1, label => 'Slave connect-retry timeout' },
   cxn                         => { hdr => 'CXN',                 num => 0, label => 'Connection from which the data came', },
   db                          => { hdr => 'DB',                  num => 0, label => 'Current database', },
   dict_mem_alloc              => { hdr => 'Dict Mem',            num => 1, label => 'Dictionary memory allocated' },
   dirty_bufs                  => { hdr => 'Dirty Buf',           num => 1, label => 'Dirty buffer pool pages' },
   dl_txn_num                  => { hdr => 'Num',                 num => 0, label => 'Deadlocked transaction number', },
   event_set                   => { hdr => 'Evt Set?',            num => 1, label => '[Win32] if a wait event is set', },
   exec_master_log_pos         => { hdr => 'Exec Master Log Pos', num => 1, label => 'Exec Master Log Position' },
   fk_name                     => { hdr => 'Constraint',          num => 0, label => 'The name of the FK constraint' },
   free_list_len               => { hdr => 'Free List Len',       num => 1, label => 'Length of the free list' },
   has_read_view               => { hdr => 'Rd View',             num => 1, label => 'Whether the transaction has a read view' },
   hash_searches_s             => { hdr => 'Hash/Sec',            num => 1, label => 'Number of hash searches/sec' },
   hash_table_size             => { hdr => 'Size',                num => 1, label => 'Number of non-hash searches/sec' },
   heap_no                     => { hdr => 'Heap',                num => 1, label => 'Heap number' },
   heap_size                   => { hdr => 'Heap',                num => 1, label => 'Heap size' },
   history_list_len            => { hdr => 'History',             num => 1, label => 'History list length' },
   host_and_domain             => { hdr => 'Host',                num => 0, label => 'Hostname/IP and domain' },
   host_and_port               => { hdr => 'Host/IP',             num => 0, label => 'Hostname or IP address, and port number', },
   hostname                    => { hdr => 'Host',                num => 0, label => 'Hostname' },
   index                       => { hdr => 'Index',               num => 0, label => 'The index involved' },
   index_ref                   => { hdr => 'Index Ref',           num => 0, label => 'Index referenced' },
   info                        => { hdr => 'Query',               num => 0, label => 'Info or the current query', },
   insert_intention            => { hdr => 'Ins Intent',          num => 1, label => 'Whether the thread was trying to insert' },
   inserts                     => { hdr => 'Inserts',             num => 1, label => 'Inserts' },
   io_bytes_s                  => { hdr => 'Bytes/Sec',           num => 1, label => 'Average I/O bytes/sec' },
   io_flush_type               => { hdr => 'Flush Type',          num => 0, label => 'I/O Flush Type' },
   io_fsyncs_s                 => { hdr => 'fsyncs/sec',          num => 1, label => 'I/O fsyncs/sec' },
   io_reads_s                  => { hdr => 'Reads/Sec',           num => 1, label => 'Average I/O reads/sec' },
   io_writes_s                 => { hdr => 'Writes/Sec',          num => 1, label => 'Average I/O writes/sec' },
   ip                          => { hdr => 'IP',                  num => 0, label => 'IP address' },
   is_name_locked              => { hdr => 'Locked',              num => 1, label => 'Whether table is name locked', },
   key_buffer_hit              => { hdr => 'KCacheHit',           num => 1, label => 'Key cache hit ratio', },
   key_len                     => { hdr => 'Key Length',          num => 1, label => 'Number of bytes used in the key' },
   last_chkp                   => { hdr => 'Last Checkpoint',     num => 0, label => 'Last log checkpoint' },
   last_errno                  => { hdr => 'Last Errno',          num => 1, label => 'Last error number' },
   last_error                  => { hdr => 'Last Error',          num => 0, label => 'Last error' },
   last_s_file_name            => { hdr => 'S-File',              num => 0, label => 'Filename where last read locked' },
   last_s_line                 => { hdr => 'S-Line',              num => 1, label => 'Line where last read locked' },
   last_x_file_name            => { hdr => 'X-File',              num => 0, label => 'Filename where last write locked' },
   last_x_line                 => { hdr => 'X-Line',              num => 1, label => 'Line where last write locked' },
   last_pct                    => { hdr => 'Pct',                 num => 1, label => 'Last Percentage' },
   last_total                  => { hdr => 'Last Total',          num => 1, label => 'Last Total' },
   last_value                  => { hdr => 'Last Incr',           num => 1, label => 'Last Value' },
   load                        => { hdr => 'Load',                num => 1, label => 'Server load' },
   lock_cfile_name             => { hdr => 'Crtd File',           num => 0, label => 'Filename where lock created' },
   lock_cline                  => { hdr => 'Crtd Line',           num => 1, label => 'Line where lock created' },
   lock_mem_addr               => { hdr => 'Addr',                num => 0, label => 'The lock memory address' },
   lock_mode                   => { hdr => 'Mode',                num => 0, label => 'The lock mode' },
   lock_structs                => { hdr => 'LStrcts',             num => 1, label => 'Number of lock structs' },
   lock_type                   => { hdr => 'Type',                num => 0, label => 'The lock type' },
   lock_var                    => { hdr => 'Lck Var',             num => 1, label => 'The lock variable' },
   lock_wait_time              => { hdr => 'Wait',                num => 1, label => 'How long txn has waited for a lock' },
   log_flushed_to              => { hdr => 'Flushed To',          num => 0, label => 'Log position flushed to' },
   log_ios_done                => { hdr => 'IO Done',             num => 1, label => 'Log I/Os done' },
   log_ios_s                   => { hdr => 'IO/Sec',              num => 1, label => 'Average log I/Os per sec' },
   log_seq_no                  => { hdr => 'Sequence No.',        num => 0, label => 'Log sequence number' },
   main_thread_id              => { hdr => 'Main Thread ID',      num => 1, label => 'Main thread ID' },
   main_thread_proc_no         => { hdr => 'Main Thread Proc',    num => 1, label => 'Main thread process number' },
   main_thread_state           => { hdr => 'Main Thread State',   num => 0, label => 'Main thread state' },
   master_file                 => { hdr => 'File',                num => 0, label => 'Master file' },
   master_host                 => { hdr => 'Master',              num => 0, label => 'Master server hostname' },
   master_log_file             => { hdr => 'Master Log File',     num => 0, label => 'Master log file' },
   master_port                 => { hdr => 'Master Port',         num => 1, label => 'Master port' },
   master_pos                  => { hdr => 'Position',            num => 1, label => 'Master position' },
   master_ssl_allowed          => { hdr => 'Master SSL Allowed',  num => 0, label => 'Master SSL Allowed' },
   master_ssl_ca_file          => { hdr => 'Master SSL CA File',  num => 0, label => 'Master SSL Cert Auth File' },
   master_ssl_ca_path          => { hdr => 'Master SSL CA Path',  num => 0, label => 'Master SSL Cert Auth Path' },
   master_ssl_cert             => { hdr => 'Master SSL Cert',     num => 0, label => 'Master SSL Cert' },
   master_ssl_cipher           => { hdr => 'Master SSL Cipher',   num => 0, label => 'Master SSL Cipher' },
   master_ssl_key              => { hdr => 'Master SSL Key',      num => 0, label => 'Master SSL Key' },
   master_user                 => { hdr => 'Master User',         num => 0, label => 'Master username' },
   max_txn                     => { hdr => 'MaxTxnTime',          num => 1, label => 'MaxTxn' },
   merged_recs                 => { hdr => 'Merged Recs',         num => 1, label => 'Merged records' },
   merges                      => { hdr => 'Merges',              num => 1, label => 'Merges' },
   mutex_os_waits              => { hdr => 'Waits',               num => 1, label => 'Mutex OS Waits' },
   mutex_spin_rounds           => { hdr => 'Rounds',              num => 1, label => 'Mutex Spin Rounds' },
   mutex_spin_waits            => { hdr => 'Spins',               num => 1, label => 'Mutex Spin Waits' },
   mysql_thread_id             => { hdr => 'ID',                  num => 1, label => 'MySQL connection (thread) ID', },
   name                        => { hdr => 'Name',                num => 0, label => 'Variable Name' },
   n_bits                      => { hdr => '# Bits',              num => 1, label => 'Number of bits' },
   non_hash_searches_s         => { hdr => 'Non-Hash/Sec',        num => 1, label => 'Non-hash searches/sec' },
   num_deletes                 => { hdr => 'Del',                 num => 1, label => 'Number of deletes' },
   num_deletes_sec             => { hdr => 'Del/Sec',             num => 1, label => 'Number of deletes' },
   num_inserts                 => { hdr => 'Ins',                 num => 1, label => 'Number of inserts' },
   num_inserts_sec             => { hdr => 'Ins/Sec',             num => 1, label => 'Number of inserts' },
   num_readers                 => { hdr => 'Readers',             num => 1, label => 'Number of readers' },
   num_reads                   => { hdr => 'Read',                num => 1, label => 'Number of reads' },
   num_reads_sec               => { hdr => 'Read/Sec',            num => 1, label => 'Number of reads' },
   num_res_ext                 => { hdr => 'BTree Extents',       num => 1, label => 'Number of extents reserved for B-Tree' },
   num_rows                    => { hdr => 'Row Count',           num => 1, label => 'Number of rows estimated to examine' },
   num_times_open              => { hdr => 'In Use',              num => 1, label => '# times table is opened', },
   num_txns                    => { hdr => 'Txns',                num => 1, label => 'Number of transactions' },
   num_updates                 => { hdr => 'Upd',                 num => 1, label => 'Number of updates' },
   num_updates_sec             => { hdr => 'Upd/Sec',             num => 1, label => 'Number of updates' },
   os_file_reads               => { hdr => 'OS Reads',            num => 1, label => 'OS file reads' },
   os_file_writes              => { hdr => 'OS Writes',           num => 1, label => 'OS file writes' },
   os_fsyncs                   => { hdr => 'OS fsyncs',           num => 1, label => 'OS fsyncs' },
   os_thread_id                => { hdr => 'OS Thread',           num => 1, label => 'The operating system thread ID' },
   p_aio_writes                => { hdr => 'Async Wrt',           num => 1, label => 'Pending asynchronous I/O writes' },
   p_buf_pool_flushes          => { hdr => 'Buffer Pool Flushes', num => 1, label => 'Pending buffer pool flushes' },
   p_ibuf_aio_reads            => { hdr => 'IBuf Async Rds',      num => 1, label => 'Pending insert buffer asynch I/O reads' },
   p_log_flushes               => { hdr => 'Log Flushes',         num => 1, label => 'Pending log flushes' },
   p_log_ios                   => { hdr => 'Log I/Os',            num => 1, label => 'Pending log I/O operations' },
   p_normal_aio_reads          => { hdr => 'Async Rds',           num => 1, label => 'Pending asynchronous I/O reads' },
   p_preads                    => { hdr => 'preads',              num => 1, label => 'Pending p-reads' },
   p_pwrites                   => { hdr => 'pwrites',             num => 1, label => 'Pending p-writes' },
   p_sync_ios                  => { hdr => 'Sync I/Os',           num => 1, label => 'Pending synchronous I/O operations' },
   page_creates_sec            => { hdr => 'Creates/Sec',         num => 1, label => 'Page creates/sec' },
   page_no                     => { hdr => 'Page',                num => 1, label => 'Page number' },
   page_reads_sec              => { hdr => 'Reads/Sec',           num => 1, label => 'Page reads per second' },
   page_writes_sec             => { hdr => 'Writes/Sec',          num => 1, label => 'Page writes per second' },
   pages_created               => { hdr => 'Created',             num => 1, label => 'Pages created' },
   pages_modified              => { hdr => 'Dirty Pages',         num => 1, label => 'Pages modified (dirty)' },
   pages_read                  => { hdr => 'Reads',               num => 1, label => 'Pages read' },
   pages_total                 => { hdr => 'Pages',               num => 1, label => 'Pages total' },
   pages_written               => { hdr => 'Writes',              num => 1, label => 'Pages written' },
   parent_col                  => { hdr => 'Parent Column',       num => 0, label => 'The referred column in the parent table', },
   parent_db                   => { hdr => 'Parent DB',           num => 0, label => 'The database of the parent table' },
   parent_index                => { hdr => 'Parent Index',        num => 0, label => 'The referred index in the parent table' },
   parent_table                => { hdr => 'Parent Table',        num => 0, label => 'The parent table' },
   part_id                     => { hdr => 'Part ID',             num => 1, label => 'Sub-part ID of the query' },
   partitions                  => { hdr => 'Partitions',          num => 0, label => 'Query partitions used' },
   pct                         => { hdr => 'Pct',                 num => 1, label => 'Percentage' },
   pending_chkp_writes         => { hdr => 'Chkpt Writes',        num => 1, label => 'Pending log checkpoint writes' },
   pending_log_writes          => { hdr => 'Log Writes',          num => 1, label => 'Pending log writes' },
   port                        => { hdr => 'Port',                num => 1, label => 'Client port number', },
   possible_keys               => { hdr => 'Poss. Keys',          num => 0, label => 'Possible keys' },
   proc_no                     => { hdr => 'Proc',                num => 1, label => 'Process number' },
   q_cache_hit                 => { hdr => 'QCacheHit',           num => 1, label => 'Query cache hit ratio', },
   qps                         => { hdr => 'QPS',                 num => 1, label => 'How many queries/sec', },
   queries_in_queue            => { hdr => 'Queries Queued',      num => 1, label => 'Queries in queue' },
   queries_inside              => { hdr => 'Queries Inside',      num => 1, label => 'Queries inside InnoDB' },
   query_id                    => { hdr => 'Query ID',            num => 1, label => 'Query ID' },
   query_status                => { hdr => 'Query Status',        num => 0, label => 'The query status' },
   query_text                  => { hdr => 'Query Text',          num => 0, label => 'The query text' },
   questions                   => { hdr => 'Questions',           num => 1, label => 'How many queries the server has gotten', },
   read_master_log_pos         => { hdr => 'Read Master Pos',     num => 1, label => 'Read master log position' },
   read_views_open             => { hdr => 'Rd Views',            num => 1, label => 'Number of read views open' },
   reads_pending               => { hdr => 'Pending Reads',       num => 1, label => 'Reads pending' },
   relay_log_file              => { hdr => 'Relay File',          num => 0, label => 'Relay log file' },
   relay_log_pos               => { hdr => 'Relay Pos',           num => 1, label => 'Relay log position' },
   relay_log_size              => { hdr => 'Relay Size',          num => 1, label => 'Relay log size' },
   relay_master_log_file       => { hdr => 'Relay Master File',   num => 0, label => 'Relay master log file' },
   replicate_do_db             => { hdr => 'Do DB',               num => 0, label => 'Replicate-do-db setting' },
   replicate_do_table          => { hdr => 'Do Table',            num => 0, label => 'Replicate-do-table setting' },
   replicate_ignore_db         => { hdr => 'Ignore DB',           num => 0, label => 'Replicate-ignore-db setting' },
   replicate_ignore_table      => { hdr => 'Ignore Table',        num => 0, label => 'Replicate-do-table setting' },
   replicate_wild_do_table     => { hdr => 'Wild Do Table',       num => 0, label => 'Replicate-wild-do-table setting' },
   replicate_wild_ignore_table => { hdr => 'Wild Ignore Table',   num => 0, label => 'Replicate-wild-ignore-table setting' },
   request_type                => { hdr => 'Type',                num => 0, label => 'Type of lock the thread waits for' },
   reservation_count           => { hdr => 'ResCnt',              num => 1, label => 'Reservation Count' },
   row_locks                   => { hdr => 'RLocks',              num => 1, label => 'Number of row locks' },
   rw_excl_os_waits            => { hdr => 'RW Waits',            num => 1, label => 'R/W Excl. OS Waits' },
   rw_excl_spins               => { hdr => 'RW Spins',            num => 1, label => 'R/W Excl. Spins' },
   rw_shared_os_waits          => { hdr => 'Sh Waits',            num => 1, label => 'R/W Shared OS Waits' },
   rw_shared_spins             => { hdr => 'Sh Spins',            num => 1, label => 'R/W Shared Spins' },
   scan_type                   => { hdr => 'Type',                num => 0, label => 'Scan type in chosen' },
   seg_size                    => { hdr => 'Seg. Size',           num => 1, label => 'Segment size' },
   select_type                 => { hdr => 'Select Type',         num => 0, label => 'Type of select used' },
   signal_count                => { hdr => 'Signals',             num => 1, label => 'Signal Count' },
   size                        => { hdr => 'Size',                num => 1, label => 'Size of the tablespace' },
   skip_counter                => { hdr => 'Skip Counter',        num => 1, label => 'Skip counter' },
   slave_catchup_rate          => { hdr => 'Catchup',             num => 1, label => 'How fast the slave is catching up in the binlog' },
   slave_io_running            => { hdr => 'Slave-IO',            num => 0, label => 'Whether the slave I/O thread is running' },
   slave_io_state              => { hdr => 'Slave IO State',      num => 0, label => 'Slave I/O thread state' },
   slave_open_temp_tables      => { hdr => 'Temp',                num => 1, label => 'Slave open temp tables' },
   slave_sql_running           => { hdr => 'Slave-SQL',           num => 0, label => 'Whether the slave SQL thread is running' },
   slow                        => { hdr => 'Slow',                num => 1, label => 'How many slow queries', },
   space_id                    => { hdr => 'Space',               num => 1, label => 'Tablespace ID' },
   special                     => { hdr => 'Special',             num => 0, label => 'Special/Other info' },
   state                       => { hdr => 'State',               num => 0, label => 'Connection state', maxw => 18, },
   tables_in_use               => { hdr => 'Tbl Used',            num => 1, label => 'Number of tables in use' },
   tables_locked               => { hdr => 'Tbl Lck',             num => 1, label => 'Number of tables locked' },
   tbl                         => { hdr => 'Table',               num => 0, label => 'Table', },
   thread                      => { hdr => 'Thread',              num => 1, label => 'Thread number' },
   thread_decl_inside          => { hdr => 'Thread Inside',       num => 0, label => 'What the thread is declared inside' },
   thread_purpose              => { hdr => 'Purpose',             num => 0, label => "The thread's purpose" },
   thread_status               => { hdr => 'Thread Status',       num => 0, label => 'The thread status' },
   time                        => { hdr => 'Time',                num => 1, label => 'Time since the last event', },
   time_behind_master          => { hdr => 'TimeLag',             num => 1, label => 'Time slave lags master' },
   timestring                  => { hdr => 'Timestring',          num => 0, label => 'Time the event occurred' },
   total                       => { hdr => 'Total',               num => 1, label => 'Total' },
   total_mem_alloc             => { hdr => 'Memory',              num => 1, label => 'Total memory allocated' },
   truncates                   => { hdr => 'Trunc',               num => 0, label => 'Whether the deadlock is truncating InnoDB status' },
   txn_doesnt_see_ge           => { hdr => "Txn Won't See",       num => 0, label => 'Where txn read view is limited' },
   txn_id                      => { hdr => 'ID',                  num => 0, label => 'Transaction ID' },
   txn_sees_lt                 => { hdr => 'Txn Sees',            num => 1, label => 'Where txn read view is limited' },
   txn_status                  => { hdr => 'Txn Status',          num => 0, label => 'Transaction status' },
   txn_time_remain             => { hdr => 'Remaining',           num => 1, label => 'Time until txn rollback/commit completes' },
   undo_log_entries            => { hdr => 'Undo',                num => 1, label => 'Number of undo log entries' },
   undo_for                    => { hdr => 'Undo',                num => 0, label => 'Undo for' },
   until_condition             => { hdr => 'Until Condition',     num => 0, label => 'Slave until condition' },
   until_log_file              => { hdr => 'Until Log File',      num => 0, label => 'Slave until log file' },
   until_log_pos               => { hdr => 'Until Log Pos',       num => 1, label => 'Slave until log position' },
   used_cells                  => { hdr => 'Cells Used',          num => 1, label => 'Number of cells used' },
   used_bufs                   => { hdr => 'Used Bufs',           num => 1, label => 'Number of buffer pool pages used' },
   user                        => { hdr => 'User',                num => 0, label => 'Database username', },
   value                       => { hdr => 'Value',               num => 1, label => 'Value' },
   versions                    => { hdr => 'Versions',            num => 1, label => 'Number of InnoDB MVCC versions unpurged' },
   victim                      => { hdr => 'Victim',              num => 0, label => 'Whether this txn was the deadlock victim' },
   wait_array_size             => { hdr => 'Wait Array Size',     num => 1, label => 'Wait Array Size' },
   wait_status                 => { hdr => 'Lock Status',         num => 0, label => 'Status of txn locks' },
   waited_at_filename          => { hdr => 'File',                num => 0, label => 'Filename at which thread waits' },
   waited_at_line              => { hdr => 'Line',                num => 1, label => 'Line at which thread waits' },
   waiters_flag                => { hdr => 'Waiters',             num => 1, label => 'Waiters Flag' },
   waiting                     => { hdr => 'Waiting',             num => 1, label => 'Whether lock is being waited for' },
   when                        => { hdr => 'When',                num => 0, label => 'Time scale' },
   writer_lock_mode            => { hdr => 'Wrtr Lck Mode',       num => 0, label => 'Writer lock mode' },
   writer_thread               => { hdr => 'Wrtr Thread',         num => 1, label => 'Writer thread ID' },
   writes_pending              => { hdr => 'Writes',              num => 1, label => 'Number of writes pending' },
   writes_pending_flush_list   => { hdr => 'Flush List Writes',   num => 1, label => 'Number of flush list writes pending' },
   writes_pending_lru          => { hdr => 'LRU Writes',          num => 1, label => 'Number of LRU writes pending' },
   writes_pending_single_page  => { hdr => '1-Page Writes',       num => 1, label => 'Number of 1-page writes pending' },
);

# Apply a default property or three.  By default, columns are not width-constrained,
# aligned left, and sorted alphabetically, not numerically.
foreach my $col ( values %columns ) {
   map { $col->{$_} ||= 0 } qw(num minw maxw);
   $col->{just} = $col->{num} ? '' : '-';
}

# Filters {{{3
# This hash defines every filter that can be applied to a table.  These
# become part of tbl_meta as well.  Each filter is just an expression that
# returns true or false.
# Properties of each entry:
#  * func:   the subroutine
#  * name:   the name, repeated
#  * user:   whether it's a user-defined filter (saved in config)
#  * text:   text of the subroutine
#  * note:   explanation
my %filters = ();

# These are pre-processed to live in %filters above, by compiling them.
my %builtin_filters = (
   hide_self => {
      text => <<'      END',
         return ( !$set->{info} || $set->{info} ne 'SHOW FULL PROCESSLIST' )
             && ( !$set->{query_text}    || $set->{query_text} !~ m/INNODB STATUS$/ );
      END
      note => 'Removes the innotop processes from the list',
      tbls => [qw(innodb_transactions processlist)],
   },
   hide_inactive => {
      text => <<'      END',
         return ( !defined($set->{txn_status}) || $set->{txn_status} ne 'not started' )
             && ( !defined($set->{cmd})        || $set->{cmd} !~ m/Sleep|Binlog Dump/ )
             && ( !defined($set->{info})       || $set->{info} =~ m/\S/               );
      END
      note => 'Removes processes which are not doing anything',
      tbls => [qw(innodb_transactions processlist)],
   },
   hide_slave_io => {
      text => <<'      END',
         return !$set->{state} || $set->{state} !~ m/^(?:Waiting for master|Has read all relay)/;
      END
      note => 'Removes slave I/O threads from the list',
      tbls => [qw(processlist slave_io_status)],
   },
   table_is_open => {
      text => <<'      END',
         return $set->{num_times_open} + $set->{is_name_locked};
      END
      note => 'Removes tables that are not in use or locked',
      tbls => [qw(open_tables)],
   },
   cxn_is_master => {
      text => <<'      END',
         return $set->{master_file} ? 1 : 0;
      END
      note => 'Removes servers that are not masters',
      tbls => [qw(master_status)],
   },
   cxn_is_slave => {
      text => <<'      END',
         return $set->{master_host} ? 1 : 0;
      END
      note => 'Removes servers that are not slaves',
      tbls => [qw(slave_io_status slave_sql_status)],
   },
   thd_is_not_waiting => {
      text => <<'      END',
         return $set->{thread_status} !~ m#waiting for i/o request#;
      END
      note => 'Removes idle I/O threads',
      tbls => [qw(io_threads)],
   },
);
foreach my $key ( keys %builtin_filters ) {
   my ( $sub, $err ) = compile_filter($builtin_filters{$key}->{text});
   $filters{$key} = {
      func => $sub,
      text => $builtin_filters{$key}->{text},
      user => 0,
      name => $key, # useful for later
      note => $builtin_filters{$key}->{note},
      tbls => $builtin_filters{$key}->{tbls},
   }
}

# Variable sets {{{3
# Sets (arrayrefs) of variables that are used in S mode.  They are read/written to
# the config file.
my %var_sets = (
   general => {
      text => join(
         ', ',
         'set_precision(Questions/Uptime_hires) as QPS',
         'set_precision(Com_commit/Uptime_hires) as Commit_PS',
         'set_precision((Com_rollback||0)/(Com_commit||1)) as Rollback_Commit',
         'set_precision(('
            . join('+', map { "($_||0)" }
               qw(Com_delete Com_delete_multi Com_insert Com_insert_select Com_replace
                  Com_replace_select Com_select Com_update Com_update_multi))
            . ')/(Com_commit||1)) as Write_Commit',
         'set_precision((Com_select+(Qcache_hits||0))/(('
            . join('+', map { "($_||0)" }
               qw(Com_delete Com_delete_multi Com_insert Com_insert_select Com_replace
                  Com_replace_select Com_select Com_update Com_update_multi))
            . ')||1)) as R_W_Ratio',
         'set_precision(Opened_tables/Uptime_hires) as Opens_PS',
         'percent($cur->{Open_tables}/($cur->{table_cache})) as Table_Cache_Used',
         'set_precision(Threads_created/Uptime_hires) as Threads_PS',
         'percent($cur->{Threads_cached}/($cur->{thread_cache_size}||1)) as Thread_Cache_Used',
         'percent($cur->{Max_used_connections}/($cur->{max_connections}||1)) as CXN_Used_Ever',
         'percent($cur->{Threads_connected}/($cur->{max_connections}||1)) as CXN_Used_Now',
      ),
   },
   commands => {
      text => join(
         ', ',
         qw(Uptime Questions Com_delete Com_delete_multi Com_insert
         Com_insert_select Com_replace Com_replace_select Com_select Com_update
         Com_update_multi)
      ),
   },
   query_status => {
      text => join(
         ',',
         qw( Uptime Select_full_join Select_full_range_join Select_range
         Select_range_check Select_scan Slow_queries Sort_merge_passes
         Sort_range Sort_rows Sort_scan)
      ),
   },
   innodb => {
      text => join(
         ',',
         qw( Uptime Innodb_row_lock_current_waits Innodb_row_lock_time
         Innodb_row_lock_time_avg Innodb_row_lock_time_max Innodb_row_lock_waits
         Innodb_rows_deleted Innodb_rows_inserted Innodb_rows_read
         Innodb_rows_updated)
      ),
   },
   txn => {
      text => join(
         ',',
         qw( Uptime Com_begin Com_commit Com_rollback Com_savepoint
         Com_xa_commit Com_xa_end Com_xa_prepare Com_xa_recover Com_xa_rollback
         Com_xa_start)
      ),
   },
   key_cache => {
      text => join(
         ',',
         qw( Uptime Key_blocks_not_flushed Key_blocks_unused Key_blocks_used
         Key_read_requests Key_reads Key_write_requests Key_writes )
      ),
   },
   query_cache => {
      text => join(
         ',',
         "percent($exprs{QcacheHitRatio}) as Hit_Pct",
         'set_precision((Qcache_hits||0)/(Qcache_inserts||1)) as Hit_Ins',
         'set_precision((Qcache_lowmem_prunes||0)/Uptime_hires) as Lowmem_Prunes_sec',
         'percent(1-((Qcache_free_blocks||0)/(Qcache_total_blocks||1))) as Blocks_used',
         qw( Qcache_free_blocks Qcache_free_memory Qcache_not_cached Qcache_queries_in_cache)
      ),
   },
   handler => {
      text => join(
         ',',
         qw( Uptime Handler_read_key Handler_read_first Handler_read_next
         Handler_read_prev Handler_read_rnd Handler_read_rnd_next Handler_delete
         Handler_update Handler_write)
      ),
   },
   cxns_files_threads => {
      text => join(
         ',',
         qw( Uptime Aborted_clients Aborted_connects Bytes_received Bytes_sent
         Compression Connections Created_tmp_disk_tables Created_tmp_files
         Created_tmp_tables Max_used_connections Open_files Open_streams
         Open_tables Opened_tables Table_locks_immediate Table_locks_waited
         Threads_cached Threads_connected Threads_created Threads_running)
      ),
   },
   prep_stmt => {
      text => join(
         ',',
         qw( Uptime Com_dealloc_sql Com_execute_sql Com_prepare_sql Com_reset
         Com_stmt_close Com_stmt_execute Com_stmt_fetch Com_stmt_prepare
         Com_stmt_reset Com_stmt_send_long_data )
      ),
   },
   innodb_health => {
      text => join(
         ',',
         "$exprs{OldVersions} as OldVersions",
         qw(IB_sm_mutex_spin_waits IB_sm_mutex_spin_rounds IB_sm_mutex_os_waits),
         "$exprs{NumTxns} as NumTxns",
         "$exprs{MaxTxnTime} as MaxTxnTime",
         qw(IB_ro_queries_inside IB_ro_queries_in_queue),
         "set_precision($exprs{DirtyBufs} * 100) as dirty_bufs",
         "set_precision($exprs{BufPoolFill} * 100) as buf_fill",
         qw(IB_bp_pages_total IB_bp_pages_read IB_bp_pages_written IB_bp_pages_created)
      ),
   },
   innodb_health2 => {
      text => join(
         ', ',
         'percent(1-((Innodb_buffer_pool_pages_free||0)/($cur->{Innodb_buffer_pool_pages_total}||1))) as BP_page_cache_usage',
         'percent(1-((Innodb_buffer_pool_reads||0)/(Innodb_buffer_pool_read_requests||1))) as BP_cache_hit_ratio',
         'Innodb_buffer_pool_wait_free',
         'Innodb_log_waits',
      ),
   },
   slow_queries => {
      text => join(
         ', ',
         'set_precision(Slow_queries/Uptime_hires) as Slow_PS',
         'set_precision(Select_full_join/Uptime_hires) as Full_Join_PS',
         'percent(Select_full_join/(Com_select||1)) as Full_Join_Ratio',
      ),
   },
);

# Server sets {{{3
# Defines sets of servers between which the user can quickly switch.
my %server_groups;

# Connections {{{3
# This hash defines server connections.  Each connection is a string that can be passed to
# the DBI connection.  These are saved in the connections section in the config file.
my %connections;
# Defines the parts of connections.
my @conn_parts = qw(user have_user pass have_pass dsn savepass dl_table);

# Graph widths {{{3
# This hash defines the max values seen for various status/variable values, for graphing.
# These are stored in their own section in the config file.  These are just initial values:
my %mvs = (
   Com_select   => 50,
   Com_insert   => 50,
   Com_update   => 50,
   Com_delete   => 50,
   Questions    => 100,
);

# ###########################################################################
# Valid Term::ANSIColor color strings.
# ###########################################################################
my %ansicolors = map { $_ => 1 }
   qw( black blink blue bold clear concealed cyan dark green magenta on_black
       on_blue on_cyan on_green on_magenta on_red on_white on_yellow red reset
       reverse underline underscore white yellow);

# ###########################################################################
# Valid comparison operators for color rules
# ###########################################################################
my %comp_ops = (
   '==' => 'Numeric equality',
   '>'  => 'Numeric greater-than',
   '<'  => 'Numeric less-than',
   '>=' => 'Numeric greater-than/equal',
   '<=' => 'Numeric less-than/equal',
   '!=' => 'Numeric not-equal',
   'eq' => 'String equality',
   'gt' => 'String greater-than',
   'lt' => 'String less-than',
   'ge' => 'String greater-than/equal',
   'le' => 'String less-than/equal',
   'ne' => 'String not-equal',
   '=~' => 'Pattern match',
   '!~' => 'Negated pattern match',
);

# ###########################################################################
# Valid aggregate functions.
# ###########################################################################
my %agg_funcs = (
   first => sub {
      return $_[0]
   },
   count => sub {
      return 0 + @_;
   },
   avg   => sub {
      my @args = grep { defined $_ } @_;
      return (sum(map { m/([\d\.-]+)/g } @args) || 0) / (scalar(@args) || 1);
   },
   sum   => sub {
      my @args = grep { defined $_ } @_;
      return sum(@args);
   }
);

# ###########################################################################
# Valid functions for transformations.
# ###########################################################################
my %trans_funcs = (
   shorten      => \&shorten,
   secs_to_time => \&secs_to_time,
   no_ctrl_char => \&no_ctrl_char,
   percent      => \&percent,
   commify      => \&commify,
   dulint_to_int => \&dulint_to_int,
   set_precision => \&set_precision,
);

# Table definitions {{{3
# This hash defines every table that can get displayed in every mode.  Each
# table specifies columns and column data sources.  The column is
# defined by the %columns hash.
#
# Example: foo => { src => 'bar' } means the foo column (look at
# $columns{foo} for its definition) gets its data from the 'bar' element of
# the current data set, whatever that is.
#
# These columns are post-processed after being defined, because they get stuff
# from %columns.  After all the config is loaded for columns, there's more
# post-processing too; the subroutines compiled from src get added to
# the hash elements for extract_values to use.
# ###########################################################################

my %tbl_meta = (
   adaptive_hash_index => {
      capt => 'Adaptive Hash Index',
      cust => {},
      cols => {
         cxn                 => { src => 'cxn' },
         hash_table_size     => { src => 'IB_ib_hash_table_size', trans => [qw(shorten)], },
         used_cells          => { src => 'IB_ib_used_cells' },
         bufs_in_node_heap   => { src => 'IB_ib_bufs_in_node_heap' },
         hash_searches_s     => { src => 'IB_ib_hash_searches_s' },
         non_hash_searches_s => { src => 'IB_ib_non_hash_searches_s' },
      },
      visible => [ qw(cxn hash_table_size used_cells bufs_in_node_heap hash_searches_s non_hash_searches_s) ],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'ib',
      group_by => [],
      aggregate => 0,
   },
   buffer_pool => {
      capt => 'Buffer Pool',
      cust => {},
      cols => {
         cxn                        => { src => 'cxn' },
         total_mem_alloc            => { src => 'IB_bp_total_mem_alloc', trans => [qw(shorten)], },
         awe_mem_alloc              => { src => 'IB_bp_awe_mem_alloc', trans => [qw(shorten)], },
         add_pool_alloc             => { src => 'IB_bp_add_pool_alloc', trans => [qw(shorten)], },
         buf_pool_size              => { src => 'IB_bp_buf_pool_size', trans => [qw(shorten)], },
         buf_free                   => { src => 'IB_bp_buf_free' },
         buf_pool_hit_rate          => { src => 'IB_bp_buf_pool_hit_rate' },
         buf_pool_reads             => { src => 'IB_bp_buf_pool_reads' },
         buf_pool_hits              => { src => 'IB_bp_buf_pool_hits' },
         dict_mem_alloc             => { src => 'IB_bp_dict_mem_alloc' },
         pages_total                => { src => 'IB_bp_pages_total' },
         pages_modified             => { src => 'IB_bp_pages_modified' },
         reads_pending              => { src => 'IB_bp_reads_pending' },
         writes_pending             => { src => 'IB_bp_writes_pending' },
         writes_pending_lru         => { src => 'IB_bp_writes_pending_lru' },
         writes_pending_flush_list  => { src => 'IB_bp_writes_pending_flush_list' },
         writes_pending_single_page => { src => 'IB_bp_writes_pending_single_page' },
         page_creates_sec           => { src => 'IB_bp_page_creates_sec' },
         page_reads_sec             => { src => 'IB_bp_page_reads_sec' },
         page_writes_sec            => { src => 'IB_bp_page_writes_sec' },
         pages_created              => { src => 'IB_bp_pages_created' },
         pages_read                 => { src => 'IB_bp_pages_read' },
         pages_written              => { src => 'IB_bp_pages_written' },
      },
      visible => [ qw(cxn buf_pool_size buf_free pages_total pages_modified buf_pool_hit_rate total_mem_alloc add_pool_alloc)],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'bp',
      group_by => [],
      aggregate => 0,
   },
   # TODO: a new step in set_to_tbl: join result to itself, grouped?
   # TODO: this would also enable pulling Q and T data together.
   # TODO: using a SQL-ish language would also allow pivots to be easier -- treat the pivoted data as a view and SELECT from it.
   cmd_summary => {
      capt => 'Command Summary',
      cust => {},
      cols => {
         name       => { src => 'name' },
         total      => { src => 'total' },
         value      => { src => 'value',                     agg   => 'sum'},
         pct        => { src => 'value/total',               trans => [qw(percent)] },
         last_total => { src => 'last_total' },
         last_value => { src => 'last_value',                agg   => 'sum'},
         last_pct   => { src => 'last_value/last_total',     trans => [qw(percent)] },
      },
      visible   => [qw(name value pct last_value last_pct)],
      filters   => [qw()],
      sort_cols => '-value',
      sort_dir  => '1',
      innodb    => '',
      group_by  => [qw(name)],
      aggregate => 1,
   },
   deadlock_locks => {
      capt => 'Deadlock Locks',
      cust => {},
      cols => {
         cxn              => { src => 'cxn' },
         mysql_thread_id  => { src => 'mysql_thread_id' },
         dl_txn_num       => { src => 'dl_txn_num' },
         lock_type        => { src => 'lock_type' },
         space_id         => { src => 'space_id' },
         page_no          => { src => 'page_no' },
         heap_no          => { src => 'heap_no' },
         n_bits           => { src => 'n_bits' },
         index            => { src => 'index' },
         db               => { src => 'db' },
         tbl              => { src => 'table' },
         lock_mode        => { src => 'lock_mode' },
         special          => { src => 'special' },
         insert_intention => { src => 'insert_intention' },
         waiting          => { src => 'waiting' },
      },
      visible => [ qw(cxn mysql_thread_id waiting lock_mode db tbl index special insert_intention)],
      filters => [],
      sort_cols => 'cxn mysql_thread_id',
      sort_dir => '1',
      innodb   => 'dl',
      group_by => [],
      aggregate => 0,
   },
   deadlock_transactions => {
      capt => 'Deadlock Transactions',
      cust => {},
      cols => {
         cxn                => { src => 'cxn' },
         active_secs        => { src => 'active_secs' },
         dl_txn_num         => { src => 'dl_txn_num' },
         has_read_view      => { src => 'has_read_view' },
         heap_size          => { src => 'heap_size' },
         host_and_domain    => { src => 'hostname' },
         hostname           => { src => $exprs{Host} },
         ip                 => { src => 'ip' },
         lock_structs       => { src => 'lock_structs' },
         lock_wait_time     => { src => 'lock_wait_time', trans => [ qw(secs_to_time) ] },
         mysql_thread_id    => { src => 'mysql_thread_id' },
         os_thread_id       => { src => 'os_thread_id' },
         proc_no            => { src => 'proc_no' },
         query_id           => { src => 'query_id' },
         query_status       => { src => 'query_status' },
         query_text         => { src => 'query_text', trans => [ qw(no_ctrl_char) ] },
         row_locks          => { src => 'row_locks' },
         tables_in_use      => { src => 'tables_in_use' },
         tables_locked      => { src => 'tables_locked' },
         thread_decl_inside => { src => 'thread_decl_inside' },
         thread_status      => { src => 'thread_status' },
         'time'             => { src => 'active_secs', trans => [ qw(secs_to_time) ] },
         timestring         => { src => 'timestring' },
         txn_doesnt_see_ge  => { src => 'txn_doesnt_see_ge' },
         txn_id             => { src => 'txn_id' },
         txn_sees_lt        => { src => 'txn_sees_lt' },
         txn_status         => { src => 'txn_status' },
         truncates          => { src => 'truncates' },
         undo_log_entries   => { src => 'undo_log_entries' },
         user               => { src => 'user' },
         victim             => { src => 'victim' },
         wait_status        => { src => 'lock_wait_status' },
      },
      visible => [ qw(cxn mysql_thread_id timestring user hostname victim time undo_log_entries lock_structs query_text)],
      filters => [],
      sort_cols => 'cxn mysql_thread_id',
      sort_dir => '1',
      innodb   => 'dl',
      group_by => [],
      aggregate => 0,
   },
   explain => {
      capt => 'EXPLAIN Results',
      cust => {},
      cols => {
         part_id       => { src => 'id' },
         select_type   => { src => 'select_type' },
         tbl           => { src => 'table' },
         partitions    => { src => 'partitions' },
         scan_type     => { src => 'type' },
         possible_keys => { src => 'possible_keys' },
         index         => { src => 'key' },
         key_len       => { src => 'key_len' },
         index_ref     => { src => 'ref' },
         num_rows      => { src => 'rows' },
         special       => { src => 'extra' },
      },
      visible => [ qw(select_type tbl partitions scan_type possible_keys index key_len index_ref num_rows special)],
      filters => [],
      sort_cols => '',
      sort_dir => '1',
      innodb   => '',
      group_by => [],
      aggregate => 0,
   },
   file_io_misc => {
      capt => 'File I/O Misc',
      cust => {},
      cols => {
         cxn            => { src => 'cxn' },
         io_bytes_s     => { src => 'IB_io_avg_bytes_s' },
         io_flush_type  => { src => 'IB_io_flush_type' },
         io_fsyncs_s    => { src => 'IB_io_fsyncs_s' },
         io_reads_s     => { src => 'IB_io_reads_s' },
         io_writes_s    => { src => 'IB_io_writes_s' },
         os_file_reads  => { src => 'IB_io_os_file_reads' },
         os_file_writes => { src => 'IB_io_os_file_writes' },
         os_fsyncs      => { src => 'IB_io_os_fsyncs' },
      },
      visible => [ qw(cxn os_file_reads os_file_writes os_fsyncs io_reads_s io_writes_s io_bytes_s)],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'io',
      group_by => [],
      aggregate => 0,
   },
   fk_error => {
      capt => 'Foreign Key Error Info',
      cust => {},
      cols => {
         timestring   => { src => 'IB_fk_timestring' },
         child_db     => { src => 'IB_fk_child_db' },
         child_table  => { src => 'IB_fk_child_table' },
         child_index  => { src => 'IB_fk_child_index' },
         fk_name      => { src => 'IB_fk_fk_name' },
         parent_db    => { src => 'IB_fk_parent_db' },
         parent_table => { src => 'IB_fk_parent_table' },
         parent_col   => { src => 'IB_fk_parent_col' },
         parent_index => { src => 'IB_fk_parent_index' },
         attempted_op => { src => 'IB_fk_attempted_op' },
      },
      visible => [ qw(timestring child_db child_table child_index parent_db parent_table parent_col parent_index fk_name attempted_op)],
      filters => [],
      sort_cols => '',
      sort_dir => '1',
      innodb   => 'fk',
      group_by => [],
      aggregate => 0,
   },
   insert_buffers => {
      capt => 'Insert Buffers',
      cust => {},
      cols => {
         cxn           => { src => 'cxn' },
         inserts       => { src => 'IB_ib_inserts' },
         merged_recs   => { src => 'IB_ib_merged_recs' },
         merges        => { src => 'IB_ib_merges' },
         size          => { src => 'IB_ib_size' },
         free_list_len => { src => 'IB_ib_free_list_len' },
         seg_size      => { src => 'IB_ib_seg_size' },
      },
      visible => [ qw(cxn inserts merged_recs merges size free_list_len seg_size)],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'ib',
      group_by => [],
      aggregate => 0,
   },
   innodb_locks  => {
      capt => 'InnoDB Locks',
      cust => {},
      cols => {
         cxn              => { src => 'cxn' },
         db               => { src => 'db' },
         index            => { src => 'index' },
         insert_intention => { src => 'insert_intention' },
         lock_mode        => { src => 'lock_mode' },
         lock_type        => { src => 'lock_type' },
         lock_wait_time   => { src => 'lock_wait_time', trans => [ qw(secs_to_time) ] },
         mysql_thread_id  => { src => 'mysql_thread_id' },
         n_bits           => { src => 'n_bits' },
         page_no          => { src => 'page_no' },
         space_id         => { src => 'space_id' },
         special          => { src => 'special' },
         tbl              => { src => 'table' },
         'time'           => { src => 'active_secs', hdr => 'Active', trans => [ qw(secs_to_time) ] },
         txn_id           => { src => 'txn_id' },
         waiting          => { src => 'waiting' },
      },
      visible => [ qw(cxn mysql_thread_id lock_type waiting lock_wait_time time lock_mode db tbl index insert_intention special)],
      filters => [],
      sort_cols => 'cxn -lock_wait_time',
      sort_dir => '1',
      innodb   => 'tx',
      colors   => [
         { col => 'lock_wait_time', op => '>',  arg => 60, color => 'red' },
         { col => 'lock_wait_time', op => '>',  arg => 30, color => 'yellow' },
         { col => 'lock_wait_time', op => '>',  arg => 10, color => 'green' },
      ],
      group_by => [],
      aggregate => 0,
   },
   innodb_transactions => {
      capt => 'InnoDB Transactions',
      cust => {},
      cols => {
         cxn                => { src => 'cxn' },
         active_secs        => { src => 'active_secs' },
         has_read_view      => { src => 'has_read_view' },
         heap_size          => { src => 'heap_size' },
         hostname           => { src => $exprs{Host} },
         ip                 => { src => 'ip' },
         wait_status        => { src => 'lock_wait_status' },
         lock_wait_time     => { src => 'lock_wait_time',      trans => [ qw(secs_to_time) ] },
         lock_structs       => { src => 'lock_structs' },
         mysql_thread_id    => { src => 'mysql_thread_id' },
         os_thread_id       => { src => 'os_thread_id' },
         proc_no            => { src => 'proc_no' },
         query_id           => { src => 'query_id' },
         query_status       => { src => 'query_status' },
         query_text         => { src => 'query_text',          trans => [ qw(no_ctrl_char) ] },
         txn_time_remain    => { src => $exprs{TxnTimeRemain}, trans => [ qw(secs_to_time) ] },
         row_locks          => { src => 'row_locks' },
         tables_in_use      => { src => 'tables_in_use' },
         tables_locked      => { src => 'tables_locked' },
         thread_decl_inside => { src => 'thread_decl_inside' },
         thread_status      => { src => 'thread_status' },
         'time'             => { src => 'active_secs',         trans => [ qw(secs_to_time) ], agg => 'sum' },
         txn_doesnt_see_ge  => { src => 'txn_doesnt_see_ge' },
         txn_id             => { src => 'txn_id' },
         txn_sees_lt        => { src => 'txn_sees_lt' },
         txn_status         => { src => 'txn_status',          minw => 10, maxw => 10 },
         undo_log_entries   => { src => 'undo_log_entries' },
         user               => { src => 'user',                maxw => 10 },
         cnt                => { src => 'mysql_thread_id',     minw => 0 },
      },
      visible => [ qw(cxn cnt mysql_thread_id user hostname txn_status time undo_log_entries query_text)],
      filters => [ qw( hide_self hide_inactive ) ],
      sort_cols => '-active_secs txn_status cxn mysql_thread_id',
      sort_dir => '1',
      innodb   => 'tx',
      hide_caption => 1,
      colors   => [
         { col => 'wait_status', op => 'eq', arg => 'LOCK WAIT',   color => 'black on_red' },
         { col => 'time',        op => '>',  arg => 600,           color => 'red' },
         { col => 'time',        op => '>',  arg => 300,           color => 'yellow' },
         { col => 'time',        op => '>',  arg => 60,            color => 'green' },
         { col => 'time',        op => '>',  arg => 30,            color => 'cyan' },
         { col => 'txn_status',  op => 'eq', arg => 'not started', color => 'white' },
      ],
      group_by => [ qw(cxn txn_status) ],
      aggregate => 0,
   },
   io_threads => {
      capt => 'I/O Threads',
      cust => {},
      cols => {
         cxn            => { src => 'cxn' },
         thread         => { src => 'thread' },
         thread_purpose => { src => 'purpose' },
         event_set      => { src => 'event_set' },
         thread_status  => { src => 'state' },
      },
      visible => [ qw(cxn thread thread_purpose thread_status)],
      filters => [ qw() ],
      sort_cols => 'cxn thread',
      sort_dir => '1',
      innodb   => 'io',
      group_by => [],
      aggregate => 0,
   },
   log_statistics => {
      capt => 'Log Statistics',
      cust => {},
      cols => {
         cxn                 => { src => 'cxn' },
         last_chkp           => { src => 'IB_lg_last_chkp' },
         log_flushed_to      => { src => 'IB_lg_log_flushed_to' },
         log_ios_done        => { src => 'IB_lg_log_ios_done' },
         log_ios_s           => { src => 'IB_lg_log_ios_s' },
         log_seq_no          => { src => 'IB_lg_log_seq_no' },
         pending_chkp_writes => { src => 'IB_lg_pending_chkp_writes' },
         pending_log_writes  => { src => 'IB_lg_pending_log_writes' },
      },
      visible => [ qw(cxn log_seq_no log_flushed_to last_chkp log_ios_done log_ios_s)],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'lg',
      group_by => [],
      aggregate => 0,
   },
   master_status => {
      capt => 'Master Status',
      cust => {},
      cols => {
         cxn                         => { src => 'cxn' },
         binlog_do_db                => { src => 'binlog_do_db' },
         binlog_ignore_db            => { src => 'binlog_ignore_db' },
         master_file                 => { src => 'file' },
         master_pos                  => { src => 'position' },
         binlog_cache_overflow       => { src => '(Binlog_cache_disk_use||0)/(Binlog_cache_use||1)', trans => [ qw(percent) ] },
      },
      visible => [ qw(cxn master_file master_pos binlog_cache_overflow)],
      filters => [ qw(cxn_is_master) ],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => '',
      group_by => [],
      aggregate => 0,
   },
   pending_io => {
      capt => 'Pending I/O',
      cust => {},
      cols => {
         cxn                => { src => 'cxn' },
         p_normal_aio_reads => { src => 'IB_io_pending_normal_aio_reads' },
         p_aio_writes       => { src => 'IB_io_pending_aio_writes' },
         p_ibuf_aio_reads   => { src => 'IB_io_pending_ibuf_aio_reads' },
         p_sync_ios         => { src => 'IB_io_pending_sync_ios' },
         p_buf_pool_flushes => { src => 'IB_io_pending_buffer_pool_flushes' },
         p_log_flushes      => { src => 'IB_io_pending_log_flushes' },
         p_log_ios          => { src => 'IB_io_pending_log_ios' },
         p_preads           => { src => 'IB_io_pending_preads' },
         p_pwrites          => { src => 'IB_io_pending_pwrites' },
      },
      visible => [ qw(cxn p_normal_aio_reads p_aio_writes p_ibuf_aio_reads p_sync_ios p_log_flushes p_log_ios)],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'io',
      group_by => [],
      aggregate => 0,
   },
   open_tables => {
      capt => 'Open Tables',
      cust => {},
      cols => {
         cxn            => { src => 'cxn' },
         db             => { src => 'database' },
         tbl            => { src => 'table' },
         num_times_open => { src => 'in_use' },
         is_name_locked => { src => 'name_locked' },
      },
      visible => [ qw(cxn db tbl num_times_open is_name_locked)],
      filters => [ qw(table_is_open) ],
      sort_cols => '-num_times_open cxn db tbl',
      sort_dir => '1',
      innodb   => '',
      group_by => [],
      aggregate => 0,
   },
   page_statistics => {
      capt => 'Page Statistics',
      cust => {},
      cols => {
         cxn              => { src => 'cxn' },
         pages_read       => { src => 'IB_bp_pages_read' },
         pages_written    => { src => 'IB_bp_pages_written' },
         pages_created    => { src => 'IB_bp_pages_created' },
         page_reads_sec   => { src => 'IB_bp_page_reads_sec' },
         page_writes_sec  => { src => 'IB_bp_page_writes_sec' },
         page_creates_sec => { src => 'IB_bp_page_creates_sec' },
      },
      visible => [ qw(cxn pages_read pages_written pages_created page_reads_sec page_writes_sec page_creates_sec)],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'bp',
      group_by => [],
      aggregate => 0,
   },
   processlist => {
      capt => 'MySQL Process List',
      cust => {},
      cols => {
         cxn             => { src => 'cxn',        minw => 6,  maxw => 10 },
         mysql_thread_id => { src => 'id',         minw => 6,  maxw => 0 },
         user            => { src => 'user',       minw => 5,  maxw => 8 },
         hostname        => { src => $exprs{Host}, minw => 13, maxw => 8, },
         port            => { src => $exprs{Port}, minw => 0,  maxw => 0, },
         host_and_port   => { src => 'host',       minw => 0,  maxw => 0 },
         db              => { src => 'db',         minw => 6,  maxw => 12 },
         cmd             => { src => 'command',    minw => 5,  maxw => 0 },
         time            => { src => 'time',       minw => 5,  maxw => 0, trans => [ qw(secs_to_time) ], agg => 'sum' },
         state           => { src => 'state',      minw => 0,  maxw => 0 },
         info            => { src => 'info',       minw => 0,  maxw => 0, trans => [ qw(no_ctrl_char) ] },
         cnt             => { src => 'id',         minw => 0,  maxw => 0 },
      },
      visible => [ qw(cxn cmd cnt mysql_thread_id state user hostname db time info)],
      filters => [ qw(hide_self hide_inactive hide_slave_io) ],
      sort_cols => '-time cxn hostname mysql_thread_id',
      sort_dir => '1',
      innodb   => '',
      hide_caption => 1,
      colors   => [
         { col => 'state',       op => 'eq', arg => 'Locked',      color => 'black on_red' },
         { col => 'cmd',         op => 'eq', arg => 'Sleep',       color => 'white' },
         { col => 'user',        op => 'eq', arg => 'system user', color => 'white' },
         { col => 'cmd',         op => 'eq', arg => 'Connect',     color => 'white' },
         { col => 'cmd',         op => 'eq', arg => 'Binlog Dump', color => 'white' },
         { col => 'time',        op => '>',  arg => 600,           color => 'red' },
         { col => 'time',        op => '>',  arg => 120,           color => 'yellow' },
         { col => 'time',        op => '>',  arg => 60,            color => 'green' },
         { col => 'time',        op => '>',  arg => 30,            color => 'cyan' },
      ],
      group_by => [qw(cxn cmd)],
      aggregate => 0,
   },

   # TODO: some more columns:
   # kb_used=hdr='BufUsed' minw='0' num='0' src='percent(1 - ((Key_blocks_unused * key_cache_block_size) / (key_buffer_size||1)))' dec='0' trans='' tbl='q_header' just='-' user='1' maxw='0' label='User-defined'
   # retries=hdr='Retries' minw='0' num='0' src='Slave_retried_transactions' dec='0' trans='' tbl='slave_sql_status' just='-' user='1' maxw='0' label='User-defined'
   # thd=hdr='Thd' minw='0' num='0' src='Threads_connected' dec='0' trans='' tbl='slave_sql_status' just='-' user='1' maxw='0' label='User-defined'

   q_header => {
      capt => 'Q-mode Header',
      cust => {},
      cols => {
         cxn            => { src => 'cxn' },
         questions      => { src => 'Questions' },
         qps            => { src => 'Questions/Uptime_hires',               dec => 1, trans => [qw(shorten)] },
         load           => { src => $exprs{ServerLoad},                     dec => 1, trans => [qw(shorten)] },
         slow           => { src => 'Slow_queries',                         dec => 1, trans => [qw(shorten)] },
         q_cache_hit    => { src => $exprs{QcacheHitRatio},                 dec => 1, trans => [qw(percent)] },
         key_buffer_hit => { src => '1-(Key_reads/(Key_read_requests||1))', dec => 1, trans => [qw(percent)] },
         bps_in         => { src => 'Bytes_received/Uptime_hires',          dec => 1, trans => [qw(shorten)] },
         bps_out        => { src => 'Bytes_sent/Uptime_hires',              dec => 1, trans => [qw(shorten)] },
         when           => { src => 'when' },
      },
      visible => [ qw(cxn when load qps slow q_cache_hit key_buffer_hit bps_in bps_out)],
      filters => [],
      sort_cols => 'when cxn',
      sort_dir => '1',
      innodb   => '',
      hide_caption => 1,
      group_by => [],
      aggregate => 0,
   },
   row_operations => {
      capt => 'InnoDB Row Operations',
      cust => {},
      cols => {
         cxn         => { src => 'cxn' },
         num_inserts => { src => 'IB_ro_num_rows_ins' },
         num_updates => { src => 'IB_ro_num_rows_upd' },
         num_reads   => { src => 'IB_ro_num_rows_read' },
         num_deletes => { src => 'IB_ro_num_rows_del' },
         num_inserts_sec => { src => 'IB_ro_ins_sec' },
         num_updates_sec => { src => 'IB_ro_upd_sec' },
         num_reads_sec   => { src => 'IB_ro_read_sec' },
         num_deletes_sec => { src => 'IB_ro_del_sec' },
      },
      visible => [ qw(cxn num_inserts num_updates num_reads num_deletes num_inserts_sec
                       num_updates_sec num_reads_sec num_deletes_sec)],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'ro',
      group_by => [],
      aggregate => 0,
   },
   row_operation_misc => {
      capt => 'Row Operation Misc',
      cust => {},
      cols => {
         cxn                 => { src => 'cxn' },
         queries_in_queue    => { src => 'IB_ro_queries_in_queue' },
         queries_inside      => { src => 'IB_ro_queries_inside' },
         read_views_open     => { src => 'IB_ro_read_views_open' },
         main_thread_id      => { src => 'IB_ro_main_thread_id' },
         main_thread_proc_no => { src => 'IB_ro_main_thread_proc_no' },
         main_thread_state   => { src => 'IB_ro_main_thread_state' },
         num_res_ext         => { src => 'IB_ro_n_reserved_extents' },
      },
      visible => [ qw(cxn queries_in_queue queries_inside read_views_open main_thread_state)],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'ro',
      group_by => [],
      aggregate => 0,
   },
   semaphores => {
      capt => 'InnoDB Semaphores',
      cust => {},
      cols => {
         cxn                => { src => 'cxn' },
         mutex_os_waits     => { src => 'IB_sm_mutex_os_waits' },
         mutex_spin_rounds  => { src => 'IB_sm_mutex_spin_rounds' },
         mutex_spin_waits   => { src => 'IB_sm_mutex_spin_waits' },
         reservation_count  => { src => 'IB_sm_reservation_count' },
         rw_excl_os_waits   => { src => 'IB_sm_rw_excl_os_waits' },
         rw_excl_spins      => { src => 'IB_sm_rw_excl_spins' },
         rw_shared_os_waits => { src => 'IB_sm_rw_shared_os_waits' },
         rw_shared_spins    => { src => 'IB_sm_rw_shared_spins' },
         signal_count       => { src => 'IB_sm_signal_count' },
         wait_array_size    => { src => 'IB_sm_wait_array_size' },
      },
      visible => [ qw(cxn mutex_os_waits mutex_spin_waits mutex_spin_rounds
         rw_excl_os_waits rw_excl_spins rw_shared_os_waits rw_shared_spins
         signal_count reservation_count )],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'sm',
      group_by => [],
      aggregate => 0,
   },
   slave_io_status => {
      capt => 'Slave I/O Status',
      cust => {},
      cols => {
         cxn                         => { src => 'cxn' },
         connect_retry               => { src => 'connect_retry' },
         master_host                 => { src => 'master_host', hdr => 'Master'},
         master_log_file             => { src => 'master_log_file', hdr => 'File' },
         master_port                 => { src => 'master_port' },
         master_ssl_allowed          => { src => 'master_ssl_allowed' },
         master_ssl_ca_file          => { src => 'master_ssl_ca_file' },
         master_ssl_ca_path          => { src => 'master_ssl_ca_path' },
         master_ssl_cert             => { src => 'master_ssl_cert' },
         master_ssl_cipher           => { src => 'master_ssl_cipher' },
         master_ssl_key              => { src => 'master_ssl_key' },
         master_user                 => { src => 'master_user' },
         read_master_log_pos         => { src => 'read_master_log_pos', hdr => 'Pos' },
         relay_log_size              => { src => 'relay_log_space', trans => [qw(shorten)] },
         slave_io_running            => { src => 'slave_io_running', hdr => 'On?' },
         slave_io_state              => { src => 'slave_io_state', hdr => 'State' },
      },
      visible => [ qw(cxn master_host slave_io_running master_log_file relay_log_size read_master_log_pos slave_io_state)],
      filters => [ qw( cxn_is_slave ) ],
      sort_cols => 'slave_io_running cxn',
      colors   => [
         { col => 'slave_io_running',  op => 'ne', arg => 'Yes', color => 'black on_red' },
      ],
      sort_dir => '1',
      innodb   => '',
      group_by => [],
      aggregate => 0,
   },
   slave_sql_status => {
      capt => 'Slave SQL Status',
      cust => {},
      cols => {
         cxn                         => { src => 'cxn' },
         exec_master_log_pos         => { src => 'exec_master_log_pos', hdr => 'Master Pos' },
         last_errno                  => { src => 'last_errno' },
         last_error                  => { src => 'last_error' },
         master_host                 => { src => 'master_host', hdr => 'Master' },
         relay_log_file              => { src => 'relay_log_file' },
         relay_log_pos               => { src => 'relay_log_pos' },
         relay_log_size              => { src => 'relay_log_space', trans => [qw(shorten)] },
         relay_master_log_file       => { src => 'relay_master_log_file', hdr => 'Master File' },
         replicate_do_db             => { src => 'replicate_do_db' },
         replicate_do_table          => { src => 'replicate_do_table' },
         replicate_ignore_db         => { src => 'replicate_ignore_db' },
         replicate_ignore_table      => { src => 'replicate_ignore_table' },
         replicate_wild_do_table     => { src => 'replicate_wild_do_table' },
         replicate_wild_ignore_table => { src => 'replicate_wild_ignore_table' },
         skip_counter                => { src => 'skip_counter' },
         slave_sql_running           => { src => 'slave_sql_running', hdr => 'On?' },
         until_condition             => { src => 'until_condition' },
         until_log_file              => { src => 'until_log_file' },
         until_log_pos               => { src => 'until_log_pos' },
         time_behind_master          => { src => 'seconds_behind_master', trans => [ qw(secs_to_time) ] },
         bytes_behind_master         => { src => 'master_log_file && master_log_file eq relay_master_log_file ? read_master_log_pos - exec_master_log_pos : 0', trans => [qw(shorten)] },
         slave_catchup_rate          => { src => $exprs{SlaveCatchupRate}, trans => [ qw(set_precision) ] },
         slave_open_temp_tables      => { src => 'Slave_open_temp_tables' },
      },
      visible => [ qw(cxn master_host slave_sql_running time_behind_master slave_catchup_rate slave_open_temp_tables relay_log_pos last_error)],
      filters => [ qw( cxn_is_slave ) ],
      sort_cols => 'slave_sql_running cxn',
      sort_dir => '1',
      innodb   => '',
      colors   => [
         { col => 'slave_sql_running',  op => 'ne', arg => 'Yes', color => 'black on_red' },
         { col => 'time_behind_master', op => '>',  arg => 600,   color => 'red' },
         { col => 'time_behind_master', op => '>',  arg => 60,    color => 'yellow' },
         { col => 'time_behind_master', op => '==', arg => 0,     color => 'white' },
      ],
      group_by => [],
      aggregate => 0,
   },
   t_header => {
      capt => 'T-Mode Header',
      cust => {},
      cols => {
         cxn                         => { src => 'cxn' },
         dirty_bufs                  => { src => $exprs{DirtyBufs},           trans => [qw(percent)] },
         history_list_len            => { src => 'IB_tx_history_list_len' },
         lock_structs                => { src => 'IB_tx_num_lock_structs' },
         num_txns                    => { src => $exprs{NumTxns} },
         max_txn                     => { src => $exprs{MaxTxnTime},          trans => [qw(secs_to_time)] },
         undo_for                    => { src => 'IB_tx_purge_undo_for' },
         used_bufs                   => { src => $exprs{BufPoolFill},         trans => [qw(percent)]},
         versions                    => { src => $exprs{OldVersions} },
      },
      visible => [ qw(cxn history_list_len versions undo_for dirty_bufs used_bufs num_txns max_txn lock_structs)],
      filters => [ ],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => '',
      colors   => [],
      hide_caption => 1,
      group_by => [],
      aggregate => 0,
   },
   var_status => {
      capt      => 'Variables & Status',
      cust      => {},
      cols      => {}, # Generated from current varset
      visible   => [], # Generated from current varset
      filters   => [],
      sort_cols => '',
      sort_dir  => 1,
      innodb    => '',
      temp      => 1, # Do not persist to config file.
      hide_caption  => 1,
      pivot     => 0,
      group_by => [],
      aggregate => 0,
   },
   wait_array => {
      capt => 'InnoDB Wait Array',
      cust => {},
      cols => {
         cxn                => { src => 'cxn' },
         thread             => { src => 'thread' },
         waited_at_filename => { src => 'waited_at_filename' },
         waited_at_line     => { src => 'waited_at_line' },
         'time'             => { src => 'waited_secs', trans => [ qw(secs_to_time) ] },
         request_type       => { src => 'request_type' },
         lock_mem_addr      => { src => 'lock_mem_addr' },
         lock_cfile_name    => { src => 'lock_cfile_name' },
         lock_cline         => { src => 'lock_cline' },
         writer_thread      => { src => 'writer_thread' },
         writer_lock_mode   => { src => 'writer_lock_mode' },
         num_readers        => { src => 'num_readers' },
         lock_var           => { src => 'lock_var' },
         waiters_flag       => { src => 'waiters_flag' },
         last_s_file_name   => { src => 'last_s_file_name' },
         last_s_line        => { src => 'last_s_line' },
         last_x_file_name   => { src => 'last_x_file_name' },
         last_x_line        => { src => 'last_x_line' },
         cell_waiting       => { src => 'cell_waiting' },
         cell_event_set     => { src => 'cell_event_set' },
      },
      visible => [ qw(cxn thread time waited_at_filename waited_at_line request_type num_readers lock_var waiters_flag cell_waiting cell_event_set)],
      filters => [],
      sort_cols => 'cxn -time',
      sort_dir => '1',
      innodb   => 'sm',
      group_by => [],
      aggregate => 0,
   },
);

# Initialize %tbl_meta from %columns and do some checks.
foreach my $table_name ( keys %tbl_meta ) {
   my $table = $tbl_meta{$table_name};
   my $cols  = $table->{cols};

   foreach my $col_name ( keys %$cols ) {
      my $col_def = $table->{cols}->{$col_name};
      die "I can't find a column named '$col_name' for '$table_name'" unless $columns{$col_name};
      $columns{$col_name}->{referenced} = 1;

      foreach my $prop ( keys %col_props ) {
         # Each column gets non-existing values set from %columns or defaults from %col_props.
         if ( !$col_def->{$prop} ) {
            $col_def->{$prop}
               = defined($columns{$col_name}->{$prop})
               ? $columns{$col_name}->{$prop}
               : $col_props{$prop};
         }
      }

      # Ensure transformations and aggregate functions are valid
      die "Unknown aggregate function '$col_def->{agg}' "
         . "for column '$col_name' in table '$table_name'"
         unless exists $agg_funcs{$col_def->{agg}};
      foreach my $trans ( @{$col_def->{trans}} ) {
         die "Unknown transformation '$trans' "
            . "for column '$col_name' in table '$table_name'"
            unless exists $trans_funcs{$trans};
      }
   }

   # Ensure each column in visible and group_by exists in cols
   foreach my $place ( qw(visible group_by) ) {
      foreach my $col_name ( @{$table->{$place}} ) {
         if ( !exists $cols->{$col_name} ) {
            die "Column '$col_name' is listed in '$place' for '$table_name', but doesn't exist";
         }
      }
   }

   # Compile sort and color subroutines
   $table->{sort_func}  = make_sort_func($table);
   $table->{color_func} = make_color_func($table);
}

# This is for code cleanup:
{
   my @unused_cols = grep { !$columns{$_}->{referenced} } sort keys %columns;
   if ( @unused_cols ) {
      die "The following columns are not used: "
         . join(' ', @unused_cols);
   }
}

# ###########################################################################
# Operating modes {{{3
# ###########################################################################
my %modes = (
   B => {
      hdr               => 'InnoDB Buffers',
      cust              => {},
      note              => 'Shows buffer info from InnoDB',
      action_for        => {
         i => {
            action => sub { toggle_config('status_inc') },
            label  => 'Toggle incremental status display',
         },
      },
      display_sub       => \&display_B,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(buffer_pool page_statistics insert_buffers adaptive_hash_index)],
      visible_tables    => [qw(buffer_pool page_statistics insert_buffers adaptive_hash_index)],
   },
   C => {
      hdr               => 'Command Summary',
      cust              => {},
      note              => 'Shows relative magnitude of variables',
      action_for        => {
         s => {
            action => sub { get_config_interactive('cmd_filter') },
            label  => 'Choose variable prefix',
         },
      },
      display_sub       => \&display_C,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(cmd_summary)],
      visible_tables    => [qw(cmd_summary)],
   },
   D => {
      hdr               => 'InnoDB Deadlocks',
      cust              => {},
      note              => 'View InnoDB deadlock information',
      action_for        => {
         c => {
            action => sub { edit_table('deadlock_transactions') },
            label  => 'Choose visible columns',
         },
         w => {
            action => \&create_deadlock,
            label  => 'Wipe deadlock status info by creating a deadlock',
         },
      },
      display_sub       => \&display_D,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(deadlock_transactions deadlock_locks)],
      visible_tables    => [qw(deadlock_transactions deadlock_locks)],
   },
   F => {
      hdr               => 'InnoDB FK Err',
      cust              => {},
      note              => 'View the latest InnoDB foreign key error',
      action_for        => {},
      display_sub       => \&display_F,
      connections       => [],
      server_group      => '',
      one_connection    => 1,
      tables            => [qw(fk_error)],
      visible_tables    => [qw(fk_error)],
   },
   I => {
      hdr               => 'InnoDB I/O Info',
      cust              => {},
      note              => 'Shows I/O info (i/o, log...) from InnoDB',
      action_for        => {
         i => {
            action => sub { toggle_config('status_inc') },
            label  => 'Toggle incremental status display',
         },
      },
      display_sub       => \&display_I,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(io_threads pending_io file_io_misc log_statistics)],
      visible_tables    => [qw(io_threads pending_io file_io_misc log_statistics)],
   },
   L => {
      hdr             => 'Locks',
      cust            => {},
      note            => 'Shows transaction locks',
      action_for      => {
         a => {
            action => sub { send_cmd_to_servers('CREATE TABLE IF NOT EXISTS test.innodb_lock_monitor(a int) ENGINE=InnoDB', 0, '', []); },
            label  => 'Start the InnoDB Lock Monitor',
         },
         o => {
            action => sub { send_cmd_to_servers('DROP TABLE IF EXISTS test.innodb_lock_monitor', 0, '', []); },
            label  => 'Stop the InnoDB Lock Monitor',
         },
      },
      display_sub     => \&display_L,
      connections     => [],
      server_group    => '',
      one_connection  => 0,
      tables            => [qw(innodb_locks)],
      visible_tables    => [qw(innodb_locks)],
   },
   M => {
      hdr               => 'Replication Status',
      cust              => {},
      note              => 'Shows replication (master and slave) status',
      action_for        => {
         a => {
            action => sub { send_cmd_to_servers('START SLAVE', 0, 'START SLAVE SQL_THREAD UNTIL MASTER_LOG_FILE = ?, MASTER_LOG_POS = ?', []); },
            label  => 'Start slave(s)',
         },
         i => {
            action => sub { toggle_config('status_inc') },
            label  => 'Toggle incremental status display',
         },
         o => {
            action => sub { send_cmd_to_servers('STOP SLAVE', 0, '', []); },
            label  => 'Stop slave(s)',
         },
         b => {
            action => sub { purge_master_logs() },
            label  => 'Purge unused master logs',
         },
      },
      display_sub       => \&display_M,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(slave_sql_status slave_io_status master_status)],
      visible_tables    => [qw(slave_sql_status slave_io_status master_status)],
   },
   O => {
      hdr               => 'Open Tables',
      cust              => {},
      note              => 'Shows open tables in MySQL',
      action_for        => {
         r => {
            action => sub { reverse_sort('open_tables'); },
            label  => 'Reverse sort order',
         },
         s => {
            action => sub { choose_sort_cols('open_tables'); },
            label => "Choose sort column",
         },
      },
      display_sub       => \&display_O,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(open_tables)],
      visible_tables    => [qw(open_tables)],
   },
   Q => {
      hdr        => 'Query List',
      cust       => {},
      note       => 'Shows queries from SHOW FULL PROCESSLIST',
      action_for => {
         a => {
            action => sub { toggle_filter('processlist', 'hide_self') },
            label  => 'Toggle the innotop process',
         },
         c => {
            action => sub { edit_table('processlist') },
            label  => 'Choose visible columns',
         },
         e => {
            action => sub { analyze_query('e'); },
            label  => "Explain a thread's query",
         },
         f => {
            action => sub { analyze_query('f'); },
            label  => "Show a thread's full query",
         },
         h => {
            action => sub { toggle_visible_table('Q', 'q_header') },
            label  => 'Toggle the header on and off',
         },
         i => {
            action => sub { toggle_filter('processlist', 'hide_inactive') },
            label  => 'Toggle idle processes',
         },
         k => {
            action => sub { kill_query('CONNECTION') },
            label => "Kill a query's connection",
         },
         r => {
            action => sub { reverse_sort('processlist'); },
            label  => 'Reverse sort order',
         },
         s => {
            action => sub { choose_sort_cols('processlist'); },
            label => "Change the display's sort column",
         },
         x => {
            action => sub { kill_query('QUERY') },
            label => "Kill a query",
         },
      },
      display_sub       => \&display_Q,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(q_header processlist)],
      visible_tables    => [qw(q_header processlist)],
   },
   R => {
      hdr               => 'InnoDB Row Ops',
      cust              => {},
      note              => 'Shows InnoDB row operation and semaphore info',
      action_for        => {
         i => {
            action => sub { toggle_config('status_inc') },
            label  => 'Toggle incremental status display',
         },
      },
      display_sub       => \&display_R,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(row_operations row_operation_misc semaphores wait_array)],
      visible_tables    => [qw(row_operations row_operation_misc semaphores wait_array)],
   },
   S => {
      hdr               => 'Variables & Status',
      cust              => {},
      note              => 'Shows query load statistics a la vmstat',
      action_for        => {
         '>' => {
            action => sub { switch_var_set('S_set', 1) },
            label  => 'Switch to next variable set',
         },
         '<' => {
            action => sub { switch_var_set('S_set', -1) },
            label  => 'Switch to prev variable set',
         },
         c => {
            action => sub {
               choose_var_set('S_set');
               start_S_mode();
            },
            label => "Choose which set to display",
         },
         e => {
            action => \&edit_current_var_set,
            label  => 'Edit the current set of variables',
         },
         i => {
            action => sub { $clear_screen_sub->(); toggle_config('status_inc') },
            label  => 'Toggle incremental status display',
         },
         '-' => {
            action => sub { set_display_precision(-1) },
            label  => 'Decrease fractional display precision',
         },
         '+' => {
            action => sub { set_display_precision(1) },
            label  => 'Increase fractional display precision',
         },
         g => {
            action => sub { set_s_mode('g') },
            label  => 'Switch to graph (tload) view',
         },
         s => {
            action => sub { set_s_mode('s') },
            label  => 'Switch to standard (vmstat) view',
         },
         v => {
            action => sub { set_s_mode('v') },
            label  => 'Switch to pivoted view',
         },
      },
      display_sub       => \&display_S,
      no_clear_screen   => 1,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(var_status)],
      visible_tables    => [qw(var_status)],
   },
   T => {
      hdr        => 'InnoDB Txns',
      cust       => {},
      note       => 'Shows InnoDB transactions in top-like format',
      action_for => {
         a => {
            action => sub { toggle_filter('innodb_transactions', 'hide_self') },
            label  => 'Toggle the innotop process',
         },
         c => {
            action => sub { edit_table('innodb_transactions') },
            label  => 'Choose visible columns',
         },
         e => {
            action => sub { analyze_query('e'); },
            label  => "Explain a thread's query",
         },
         f => {
            action => sub { analyze_query('f'); },
            label  => "Show a thread's full query",
         },
         h => {
            action => sub { toggle_visible_table('T', 't_header') },
            label  => 'Toggle the header on and off',
         },
         i => {
            action => sub { toggle_filter('innodb_transactions', 'hide_inactive') },
            label  => 'Toggle inactive transactions',
         },
         k => {
            action => sub { kill_query('CONNECTION') },
            label  => "Kill a transaction's connection",
         },
         r => {
            action => sub { reverse_sort('innodb_transactions'); },
            label  => 'Reverse sort order',
         },
         s => {
            action => sub { choose_sort_cols('innodb_transactions'); },
            label  => "Change the display's sort column",
         },
         x => {
            action => sub { kill_query('QUERY') },
            label  => "Kill a query",
         },
      },
      display_sub       => \&display_T,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(t_header innodb_transactions)],
      visible_tables    => [qw(t_header innodb_transactions)],
   },
);

# ###########################################################################
# Global key mappings {{{3
# Keyed on a single character, which is read from the keyboard.  Uppercase
# letters switch modes.  Lowercase letters access commands when in a mode.
# These can be overridden by action_for in %modes.
# ###########################################################################
my %action_for = (
   '$' => {
      action => \&edit_configuration,
      label  => 'Edit configuration settings',
   },
   '?' => {
      action => \&display_help,
      label  => 'Show help',
   },
   '!' => {
      action => \&display_license,
      label  => 'Show license and warranty',
   },
   '^' => {
      action => \&edit_table,
      label  => "Edit the displayed table(s)",
   },
   '#' => {
      action => \&choose_server_groups,
      label  => 'Select/create server groups',
   },
   '@' => {
      action => \&choose_servers,
      label  => 'Select/create server connections',
   },
   '/' => {
      action => \&add_quick_filter,
      label  => 'Quickly filter what you see',
   },
   '\\' => {
      action => \&clear_quick_filters,
      label  => 'Clear quick-filters',
   },
   '%' => {
      action => \&choose_filters,
      label  => 'Choose and edit table filters',
   },
   "\t" => {
      action => \&next_server_group,
      label  => 'Switch to the next server group',
      key    => 'TAB',
   },
   '=' => {
      action => \&toggle_aggregate,
      label  => 'Toggle aggregation',
   },
   # TODO: can these be auto-generated from %modes?
   B => {
      action => sub { switch_mode('B') },
      label  => '',
   },
   C => {
      action => sub { switch_mode('C') },
      label  => '',
   },
   D => {
      action => sub { switch_mode('D') },
      label  => '',
   },
   F => {
      action => sub { switch_mode('F') },
      label  => '',
   },
   I => {
      action => sub { switch_mode('I') },
      label  => '',
   },
   L => {
      action => sub { switch_mode('L') },
      label  => '',
   },
   M => {
      action => sub { switch_mode('M') },
      label  => '',
   },
   O => {
      action => sub { switch_mode('O') },
      label  => '',
   },
   Q => {
      action => sub { switch_mode('Q') },
      label  => '',
   },
   R => {
      action => sub { switch_mode('R') },
      label  => '',
   },
   S => {
      action => \&start_S_mode,
      label  => '',
   },
   T => {
      action => sub { switch_mode('T') },
      label  => '',
   },
   d => {
      action => sub { get_config_interactive('interval') },
      label  => 'Change refresh interval',
   },
   n => { action => \&next_server,       label => 'Switch to the next connection' },
   p => { action => \&pause,             label => 'Pause innotop', },
   q => { action => \&finish,            label => 'Quit innotop', },
);

# ###########################################################################
# Sleep times after certain statements {{{3
# ###########################################################################
my %stmt_sleep_time_for = ();

# ###########################################################################
# Config editor key mappings {{{3
# ###########################################################################
my %cfg_editor_action = (
   c => {
      note => 'Edit columns, etc in the displayed table(s)',
      func => \&edit_table,
   },
   g => {
      note => 'Edit general configuration',
      func => \&edit_configuration_variables,
   },
   k => {
      note => 'Edit row-coloring rules',
      func => \&edit_color_rules,
   },
   p => {
      note => 'Manage plugins',
      func => \&edit_plugins,
   },
   s => {
      note => 'Edit server groups',
      func => \&edit_server_groups,
   },
   S => {
      note => 'Edit SQL statement sleep delays',
      func => \&edit_stmt_sleep_times,
   },
   t => {
      note => 'Choose which table(s) to display in this mode',
      func => \&choose_mode_tables,
   },
);

# ###########################################################################
# Color editor key mappings {{{3
# ###########################################################################
my %color_editor_action = (
   n => {
      note => 'Create a new color rule',
      func => sub {
         my ( $tbl, $idx ) = @_;
         my $meta = $tbl_meta{$tbl};

         $clear_screen_sub->();
         my $col;
         do {
            $col = prompt_list(
               'Choose the target column for the rule',
               '',
               sub { return keys %{$meta->{cols}} },
               { map { $_ => $meta->{cols}->{$_}->{label} } keys %{$meta->{cols}} });
         } while ( !$col );
         ( $col ) = grep { $_ } split(/\W+/, $col);
         return $idx unless $col && exists $meta->{cols}->{$col};

         $clear_screen_sub->();
         my $op;
         do {
            $op = prompt_list(
               'Choose the comparison operator for the rule',
               '',
               sub { return keys %comp_ops },
               { map { $_ => $comp_ops{$_} } keys %comp_ops } );
         } until ( $op );
         $op =~ s/\s+//g;
         return $idx unless $op && exists $comp_ops{$op};

         my $arg;
         do {
            $arg = prompt('Specify an argument for the comparison');
         } until defined $arg;

         my $color;
         do {
            $color = prompt_list(
               'Choose the color(s) the row should be when the rule matches',
               '',
               sub { return keys %ansicolors },
               { map { $_ => $_ } keys %ansicolors } );
         } until defined $color;
         $color = join(' ', unique(grep { exists $ansicolors{$_} } split(/\W+/, $color)));
         return $idx unless $color;

         push @{$tbl_meta{$tbl}->{colors}}, {
            col   => $col,
            op    => $op,
            arg   => $arg,
            color => $color
         };
         $tbl_meta{$tbl}->{cust}->{colors} = 1;

         return $idx;
      },
   },
   d => {
      note => 'Remove the selected rule',
      func => sub {
         my ( $tbl, $idx ) = @_;
         my @rules = @{ $tbl_meta{$tbl}->{colors} };
         return 0 unless @rules > 0 && $idx < @rules && $idx >= 0;
         splice(@{$tbl_meta{$tbl}->{colors}}, $idx, 1);
         $tbl_meta{$tbl}->{cust}->{colors} = 1;
         return $idx == @rules ? $#rules : $idx;
      },
   },
   j => {
      note => 'Move highlight down one',
      func => sub {
         my ( $tbl, $idx ) = @_;
         my $num_rules = scalar @{$tbl_meta{$tbl}->{colors}};
         return ($idx + 1) % $num_rules;
      },
   },
   k => {
      note => 'Move highlight up one',
      func => sub {
         my ( $tbl, $idx ) = @_;
         my $num_rules = scalar @{$tbl_meta{$tbl}->{colors}};
         return ($idx - 1) % $num_rules;
      },
   },
   '+' => {
      note => 'Move selected rule up one',
      func => sub {
         my ( $tbl, $idx ) = @_;
         my $meta = $tbl_meta{$tbl};
         my $dest = $idx == 0 ? scalar(@{$meta->{colors}} - 1) : $idx - 1;
         my $temp = $meta->{colors}->[$idx];
         $meta->{colors}->[$idx]  = $meta->{colors}->[$dest];
         $meta->{colors}->[$dest] = $temp;
         $meta->{cust}->{colors} = 1;
         return $dest;
      },
   },
   '-' => {
      note => 'Move selected rule down one',
      func => sub {
         my ( $tbl, $idx ) = @_;
         my $meta = $tbl_meta{$tbl};
         my $dest = $idx == scalar(@{$meta->{colors}} - 1) ? 0 : $idx + 1;
         my $temp = $meta->{colors}->[$idx];
         $meta->{colors}->[$idx]  = $meta->{colors}->[$dest];
         $meta->{colors}->[$dest] = $temp;
         $meta->{cust}->{colors} = 1;
         return $dest;
      },
   },
);

# ###########################################################################
# Plugin editor key mappings {{{3
# ###########################################################################
my %plugin_editor_action = (
   '*' => {
      note => 'Toggle selected plugin active/inactive',
      func => sub {
         my ( $plugins, $idx ) = @_;
         my $plugin = $plugins->[$idx];
         $plugin->{active} = $plugin->{active} ? 0 : 1;
         return $idx;
      },
   },
   j => {
      note => 'Move highlight down one',
      func => sub {
         my ( $plugins, $idx ) = @_;
         return ($idx + 1) % scalar(@$plugins);
      },
   },
   k => {
      note => 'Move highlight up one',
      func => sub {
         my ( $plugins, $idx ) = @_;
         return $idx == 0 ? @$plugins - 1 : $idx - 1;
      },
   },
);

# ###########################################################################
# Table editor key mappings {{{3
# ###########################################################################
my %tbl_editor_action = (
   a => {
      note => 'Add a column to the table',
      func => sub {
         my ( $tbl, $col ) = @_;
         my @visible_cols = @{ $tbl_meta{$tbl}->{visible} };
         my %all_cols     = %{ $tbl_meta{$tbl}->{cols} };
         delete @all_cols{@visible_cols};
         my $choice = prompt_list(
            'Choose a column',
            '',
            sub { return keys %all_cols; },
            { map { $_ => $all_cols{$_}->{label} || $all_cols{$_}->{hdr} } keys %all_cols });
         if ( $all_cols{$choice} ) {
            push @{$tbl_meta{$tbl}->{visible}}, $choice;
            $tbl_meta{$tbl}->{cust}->{visible} = 1;
            return $choice;
         }
         return $col;
      },
   },
   n => {
      note => 'Create a new column and add it to the table',
      func => sub {
         my ( $tbl, $col ) = @_;

         $clear_screen_sub->();
         print word_wrap("Choose a name for the column.  This name is not displayed, and is used only "
               . "for internal reference.  It can contain only lowercase letters, numbers, "
               . "and underscores.");
         print "\n\n";
         do {
            $col = prompt("Enter column name");
            $col = '' if $col =~ m/[^a-z0-9_]/;
         } while ( !$col );

         $clear_screen_sub->();
         my $hdr;
         do {
            $hdr = prompt("Enter column header");
         } while ( !$hdr );

         $clear_screen_sub->();
         print "Choose a source for the column's data\n\n";
         my ( $src, $sub, $err );
         do {
            if ( $err ) {
               print "Error: $err\n\n";
            }
            $src = prompt("Enter column source");
            if ( $src ) {
               ( $sub, $err ) = compile_expr($src);
            }
         } until ( !$err);

         # TODO: this duplicates %col_props.
         $tbl_meta{$tbl}->{cols}->{$col} = {
            hdr   => $hdr,
            src   => $src,
            just  => '-',
            num   => 0,
            label => 'User-defined',
            user  => 1,
            tbl   => $tbl,
            minw  => 0,
            maxw  => 0,
            trans => [],
            func  => $sub,
            dec   => 0,
            agg   => 0,
            aggonly => 0,
         };

         $tbl_meta{$tbl}->{visible} = [ unique(@{$tbl_meta{$tbl}->{visible}}, $col) ];
         $tbl_meta{$tbl}->{cust}->{visible} = 1;
         return $col;
      },
   },
   d => {
      note => 'Remove selected column',
      func => sub {
         my ( $tbl, $col ) = @_;
         my @visible_cols = @{ $tbl_meta{$tbl}->{visible} };
         my $idx          = 0;
         return $col unless @visible_cols > 1;
         while ( $visible_cols[$idx] ne $col ) {
            $idx++;
         }
         $tbl_meta{$tbl}->{visible} = [ grep { $_ ne $col } @visible_cols ];
         $tbl_meta{$tbl}->{cust}->{visible} = 1;
         return $idx == $#visible_cols ? $visible_cols[$idx - 1] : $visible_cols[$idx + 1];
      },
   },
   e => {
      note => 'Edit selected column',
      func => sub {
         # TODO: make this editor hotkey-driven and give readline support.
         my ( $tbl, $col ) = @_;
         $clear_screen_sub->();
         my $meta = $tbl_meta{$tbl}->{cols}->{$col};
         my @prop = qw(hdr label src just num minw maxw trans agg); # TODO redundant

         my $answer;
         do {
            # Do what the user asked...
            if ( $answer && grep { $_ eq $answer } @prop ) {
               # Some properties are arrays, others scalars.
               my $ini = ref $col_props{$answer} ? join(' ', @{$meta->{$answer}}) : $meta->{$answer};
               my $val = prompt("New value for $answer", undef, $ini);
               $val = [ split(' ', $val) ] if ref($col_props{$answer});
               if ( $answer eq 'trans' ) {
                  $val = [ unique(grep{ exists $trans_funcs{$_} } @$val) ];
               }
               @{$meta}{$answer, 'user', 'tbl' } = ( $val, 1, $tbl );
            }

            my @display_lines = (
               '',
               "You are editing column $tbl.$col.\n",
            );

            push @display_lines, create_table2(
               \@prop,
               { map { $_ => $_ } @prop },
               { map { $_ => ref $meta->{$_} eq 'ARRAY' ? join(' ', @{$meta->{$_}})
                           : ref $meta->{$_}            ? '[expression code]'
                           :                              $meta->{$_}
                     } @prop
               },
               { sep => '  ' });
            draw_screen(\@display_lines, { raw => 1 });
            print "\n\n"; # One to add space, one to clear readline artifacts
            $answer = prompt('Edit what? (q to quit)');
         } while ( $answer ne 'q' );

         return $col;
      },
   },
   j => {
      note => 'Move highlight down one',
      func => sub {
         my ( $tbl, $col ) = @_;
         my @visible_cols = @{ $tbl_meta{$tbl}->{visible} };
         my $idx          = 0;
         while ( $visible_cols[$idx] ne $col ) {
            $idx++;
         }
         return $visible_cols[ ($idx + 1) % @visible_cols ];
      },
   },
   k => {
      note => 'Move highlight up one',
      func => sub {
         my ( $tbl, $col ) = @_;
         my @visible_cols = @{ $tbl_meta{$tbl}->{visible} };
         my $idx          = 0;
         while ( $visible_cols[$idx] ne $col ) {
            $idx++;
         }
         return $visible_cols[ $idx - 1 ];
      },
   },
   '+' => {
      note => 'Move selected column up one',
      func => sub {
         my ( $tbl, $col ) = @_;
         my $meta         = $tbl_meta{$tbl};
         my @visible_cols = @{$meta->{visible}};
         my $idx          = 0;
         while ( $visible_cols[$idx] ne $col ) {
            $idx++;
         }
         if ( $idx ) {
            $visible_cols[$idx]     = $visible_cols[$idx - 1];
            $visible_cols[$idx - 1] = $col;
            $meta->{visible}        = \@visible_cols;
         }
         else {
            shift @{$meta->{visible}};
            push @{$meta->{visible}}, $col;
         }
         $meta->{cust}->{visible} = 1;
         return $col;
      },
   },
   '-' => {
      note => 'Move selected column down one',
      func => sub {
         my ( $tbl, $col ) = @_;
         my $meta         = $tbl_meta{$tbl};
         my @visible_cols = @{$meta->{visible}};
         my $idx          = 0;
         while ( $visible_cols[$idx] ne $col ) {
            $idx++;
         }
         if ( $idx == $#visible_cols ) {
            unshift @{$meta->{visible}}, $col;
            pop @{$meta->{visible}};
         }
         else {
            $visible_cols[$idx]     = $visible_cols[$idx + 1];
            $visible_cols[$idx + 1] = $col;
            $meta->{visible}        = \@visible_cols;
         }
         $meta->{cust}->{visible} = 1;
         return $col;
      },
   },
   f => {
      note => 'Choose filters',
      func => sub {
         my ( $tbl, $col ) = @_;
         choose_filters($tbl);
         return $col;
      },
   },
   o => {
      note => 'Edit color rules',
      func => sub {
         my ( $tbl, $col ) = @_;
         edit_color_rules($tbl);
         return $col;
      },
   },
   s => {
      note => 'Choose sort columns',
      func => sub {
         my ( $tbl, $col ) = @_;
         choose_sort_cols($tbl);
         return $col;
      },
   },
   g => {
      note => 'Choose group-by (aggregate) columns',
      func => sub {
         my ( $tbl, $col ) = @_;
         choose_group_cols($tbl);
         return $col;
      },
   },
);

# ###########################################################################
# Global variables and environment {{{2
# ###########################################################################

my @this_term_size; # w_chars, h_chars, w_pix, h_pix
my @last_term_size; # w_chars, h_chars, w_pix, h_pix
my $char;
my $windows       = $OSNAME =~ m/MSWin/;
my $have_color    = 0;
my $MAX_ULONG     = 4294967295; # 2^32-1
my $num_regex     = qr/^[+-]?(?=\d|\.)\d*(?:\.\d+)?(?:E[+-]?\d+|)$/i;
my $int_regex     = qr/^\d+$/;
my $bool_regex    = qr/^[01]$/;
my $term          = undef;
my $file          = undef; # File to watch for InnoDB monitor output
my $file_mtime    = undef; # Status of watched file
my $file_data     = undef; # Last chunk of text read from file
my $innodb_parser = InnoDBParser->new;

my $nonfatal_errs = join('|',
   'Access denied for user',
   'Unknown MySQL server host',
   'Unknown database',
   'Can\'t connect to local MySQL server through socket',
   'Can\'t connect to MySQL server on',
   'MySQL server has gone away',
   'Cannot call SHOW INNODB STATUS',
   'Access denied',
   'AutoCommit',
);

if ( !$opts{n} ) {
   require Term::ReadLine;
   $term = Term::ReadLine->new('innotop');
}

# Stores status, variables, innodb status, master/slave status etc.
# Keyed on connection name.  Each entry is a hashref of current and past data sets,
# keyed on clock tick.
my %vars;
my %info_gotten = (); # Which things have been retrieved for the current clock tick.

# Stores info on currently displayed queries: cxn, connection ID, query text.
my @current_queries;

my $lines_printed       = 0;
my $clock               = 0;   # Incremented with every wake-sleep cycle
my $clearing_deadlocks  = 0;

# If terminal coloring is available, use it.  The only function I want from
# the module is the colored() function.
eval {
   if ( !$opts{n} ) {
      if ( $windows ) {
         require Win32::Console::ANSI;
      }
      require Term::ANSIColor;
      import Term::ANSIColor qw(colored);
      $have_color = 1;
   }
};
if ( $EVAL_ERROR || $opts{n} ) {
   # If there was an error, manufacture my own colored() function that does no
   # coloring.
   *colored = sub { pop @_; @_; };
}

if ( $opts{n} ) {
   $clear_screen_sub = sub {};
}
elsif ( $windows ) {
   $clear_screen_sub = sub { $lines_printed = 0; system("cls") };
}
else {
   my $clear = `clear`;
   $clear_screen_sub = sub { $lines_printed = 0; print $clear };
}

# ###########################################################################
# Config storage. {{{2
# ###########################################################################
my %config = (
   color => {
      val  => $have_color,
      note => 'Whether to use terminal coloring',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   cmd_filter => {
      val  => 'Com_',
      note => 'Prefix for values in C mode',
      conf => [qw(C)],
   },
   plugin_dir => {
      val  => "$homepath/.innotop/plugins",
      note => 'Directory where plugins can be found',
      conf => 'ALL',
   },
   show_percent => {
      val  => 1,
      note => 'Show the % symbol after percentages',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   skip_innodb => {
      val  => 0,
      note => 'Disable SHOW INNODB STATUS',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   S_func => {
      val  => 's',
      note => 'What to display in S mode: graph, status, pivoted status',
      conf => [qw(S)],
      pat  => qr/^[gsv]$/,
   },
   cxn_timeout => {
      val  => 28800,
      note => 'Connection timeout for keeping unused connections alive',
      conf => 'ALL',
      pat  => $int_regex,
   },
   graph_char => {
      val  => '*',
      note => 'Character for drawing graphs',
      conf => [ qw(S) ],
      pat  => qr/^.$/,
   },
   show_cxn_errors_in_tbl => {
      val  => 1,
      note => 'Whether to display connection errors as rows in the table',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   hide_hdr => {
      val  => 0,
      note => 'Whether to show column headers',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   show_cxn_errors => {
      val  => 1,
      note => 'Whether to print connection errors to STDOUT',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   readonly => {
      val  => 1,
      note => 'Whether the config file is read-only',
      conf => [ qw() ],
      pat  => $bool_regex,
   },
   global => {
      val  => 1,
      note => 'Whether to show GLOBAL variables and status',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   header_highlight => {
      val  => 'bold',
      note => 'How to highlight table column headers',
      conf => 'ALL',
      pat  => qr/^(?:bold|underline)$/,
   },
   display_table_captions => {
      val  => 1,
      note => 'Whether to put captions on tables',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   charset => {
      val  => 'ascii',
      note => 'What type of characters should be displayed in queries (ascii, unicode, none)',
      conf => 'ALL',
      pat  => qr/^(?:ascii|unicode|none)$/,
   },
   auto_wipe_dl => {
      val  => 0,
      note => 'Whether to auto-wipe InnoDB deadlocks',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   max_height => {
      val  => 30,
      note => '[Win32] Max window height',
      conf => 'ALL',
   },
   debug => {
      val  => 0,
      pat  => $bool_regex,
      note => 'Debug mode (more verbose errors, uses more memory)',
      conf => 'ALL',
   },
   num_digits => {
      val  => 2,
      pat  => $int_regex,
      note => 'How many digits to show in fractional numbers and percents',
      conf => 'ALL',
   },
   debugfile => {
      val  => "$homepath/.innotop/core_dump",
      note => 'A debug file in case you are interested in error output',
   },
   show_statusbar => {
      val  => 1,
      pat  => $bool_regex,
      note => 'Whether to show the status bar in the display',
      conf => 'ALL',
   },
   mode => {
      val  => "Q",
      note => "Which mode to start in",
      cmdline => 1,
   },
   status_inc => {
      val  => 0,
      note => 'Whether to show raw or incremental values for status variables',
      pat  => $bool_regex,
   },
   interval => {
      val  => 10,
      pat  => qr/^(?:(?:\d*?[1-9]\d*(?:\.\d*)?)|(?:\d*\.\d*?[1-9]\d*))$/,
      note => "The interval at which the display will be refreshed.  Fractional values allowed.",
   },
   num_status_sets => {
      val  => 9,
      pat  => $int_regex,
      note => 'How many sets of STATUS and VARIABLES values to show',
      conf => [ qw(S) ],
   },
   S_set => {
      val  => 'general',
      pat  => qr/^\w+$/,
      note => 'Which set of variables to display in S (Variables & Status) mode',
      conf => [ qw(S) ],
   },
);

# ###########################################################################
# Config file sections {{{2
# The configuration file is broken up into sections like a .ini file.  This
# variable defines those sections and the subroutines responsible for reading
# and writing them.
# ###########################################################################
my %config_file_sections = (
   plugins => {
      reader => \&load_config_plugins,
      writer => \&save_config_plugins,
   },
   group_by => {
      reader => \&load_config_group_by,
      writer => \&save_config_group_by,
   },
   filters => {
      reader => \&load_config_filters,
      writer => \&save_config_filters,
   },
   active_filters => {
      reader => \&load_config_active_filters,
      writer => \&save_config_active_filters,
   },
   visible_tables => {
      reader => \&load_config_visible_tables,
      writer => \&save_config_visible_tables,
   },
   sort_cols => {
      reader => \&load_config_sort_cols,
      writer => \&save_config_sort_cols,
   },
   active_columns => {
      reader => \&load_config_active_columns,
      writer => \&save_config_active_columns,
   },
   tbl_meta => {
      reader => \&load_config_tbl_meta,
      writer => \&save_config_tbl_meta,
   },
   general => {
      reader => \&load_config_config,
      writer => \&save_config_config,
   },
   connections => {
      reader => \&load_config_connections,
      writer => \&save_config_connections,
   },
   active_connections => {
      reader => \&load_config_active_connections,
      writer => \&save_config_active_connections,
   },
   server_groups => {
      reader => \&load_config_server_groups,
      writer => \&save_config_server_groups,
   },
   active_server_groups => {
      reader => \&load_config_active_server_groups,
      writer => \&save_config_active_server_groups,
   },
   max_values_seen => {
      reader => \&load_config_mvs,
      writer => \&save_config_mvs,
   },
   varsets => {
      reader => \&load_config_varsets,
      writer => \&save_config_varsets,
   },
   colors => {
      reader => \&load_config_colors,
      writer => \&save_config_colors,
   },
   stmt_sleep_times => {
      reader => \&load_config_stmt_sleep_times,
      writer => \&save_config_stmt_sleep_times,
   },
);

# Config file sections have some dependencies, so they have to be read/written in order.
my @ordered_config_file_sections = qw(general plugins filters active_filters tbl_meta
   connections active_connections server_groups active_server_groups max_values_seen
   active_columns sort_cols visible_tables varsets colors stmt_sleep_times
   group_by);

# All events for which plugins may register themselves.  Entries are arrayrefs.
my %event_listener_for = map { $_ => [] }
   qw(
      extract_values
      set_to_tbl_pre_filter set_to_tbl_pre_sort set_to_tbl_pre_group
      set_to_tbl_pre_colorize set_to_tbl_pre_transform set_to_tbl_pre_pivot
      set_to_tbl_pre_create set_to_tbl_post_create
      draw_screen
   );

# All variables to which plugins have access.
my %pluggable_vars = (
   action_for    => \%action_for,
   agg_funcs     => \%agg_funcs,
   config        => \%config,
   connections   => \%connections,
   dbhs          => \%dbhs,
   filters       => \%filters,
   modes         => \%modes,
   server_groups => \%server_groups,
   tbl_meta      => \%tbl_meta,
   trans_funcs   => \%trans_funcs,
   var_sets      => \%var_sets,
);

# ###########################################################################
# Contains logic to generate prepared statements for a given function for a
# given DB connection.  Returns a $sth.
# ###########################################################################
my %stmt_maker_for = (
   INNODB_STATUS => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare(version_ge( $dbh, '5.0.0' )
             ? 'SHOW ENGINE INNODB STATUS'
             : 'SHOW INNODB STATUS');
   },
   SHOW_VARIABLES => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare($config{global}->{val} && version_ge( $dbh, '4.0.3' )
             ? 'SHOW GLOBAL VARIABLES'
             : 'SHOW VARIABLES');
   },
   SHOW_STATUS => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare($config{global}->{val} && version_ge( $dbh, '5.0.2' )
             ? 'SHOW GLOBAL STATUS'
             : 'SHOW STATUS');
   },
   KILL_QUERY => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare(version_ge( $dbh, '5.0.0' )
             ? 'KILL QUERY ?'
             : 'KILL ?');
   },
   SHOW_MASTER_LOGS => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare('SHOW MASTER LOGS');
   },
   SHOW_MASTER_STATUS => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare('SHOW MASTER STATUS');
   },
   SHOW_SLAVE_STATUS => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare('SHOW SLAVE STATUS');
   },
   KILL_CONNECTION => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare(version_ge( $dbh, '5.0.0' )
             ? 'KILL CONNECTION ?'
             : 'KILL ?');
   },
   OPEN_TABLES => sub {
      my ( $dbh ) = @_;
      return version_ge($dbh, '4.0.0')
         ? $dbh->prepare('SHOW OPEN TABLES')
         : undef;
   },
   PROCESSLIST => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare('SHOW FULL PROCESSLIST');
   },
);

# Plugins!
my %plugins = (
);

# ###########################################################################
# Run the program {{{1
# ###########################################################################

# This config variable is only useful for MS Windows because its terminal
# can't tell how tall it is.
if ( !$windows ) {
   delete $config{max_height};
}

# Try to lower my priority.
eval { setpriority(0, 0, getpriority(0, 0) + 10); };

# Print stuff to the screen immediately, don't wait for a newline.
$OUTPUT_AUTOFLUSH = 1;

# Clear the screen and load the configuration.
$clear_screen_sub->();
load_config();

# Override config variables with command-line options
my %cmdline =
   map  { $_->{c} => $opts{$_->{k}} }
   grep { exists $_->{c} && exists $opts{$_->{k}} }
   @opt_spec;

foreach my $name (keys %cmdline) {
   next if not defined $cmdline{$name};
   my $val = $cmdline{$name};
   if ( exists($config{$name}) and (!$config{$name}->{pat} or $val =~ m/$config{$name}->{pat}/ )) {
      $config{$name}->{val} = $val;
   }
}

post_process_tbl_meta();

# Make sure no changes are written to config file in non-interactive mode.
if ( $opts{n} ) {
   $config{readonly}->{val} = 1;
}

eval {

   # Open the file for InnoDB status
   if ( @ARGV ) {
      my $filename = shift @ARGV;
      open $file, "<", $filename
         or die "Cannot open '$filename': $OS_ERROR";
   }

   # In certain modes we might have to collect data for two cycles
   # before printing anything out, so we need to bump up the count one.
   if ( $opts{n} && $opts{count} && $config{status_inc}->{val}
      && $config{mode}->{val} =~ m/[S]/ )
   {
      $opts{count}++;
   }

   while (++$clock) {

      my $mode = $config{mode}->{val} || 'Q';
      if ( !$modes{$mode} ) {
         die "Mode '$mode' doesn't exist; try one of these:\n"
            . join("\n", map { "  $_ $modes{$_}->{hdr}" }  sort keys %modes)
            . "\n";
      }

      if ( !$opts{n} ) {
         @last_term_size = @this_term_size;
         @this_term_size = Term::ReadKey::GetTerminalSize(\*STDOUT);
         if ( $windows ) {
            $this_term_size[0]--;
            $this_term_size[1]
               = min($this_term_size[1], $config{max_height}->{val});
         }
         die("Can't read terminal size") unless @this_term_size;
      }

      # If there's no connection to a database server, we need to fix that...
      if ( !%connections ) {
         print "You have not defined any database connections.\n\n";
         add_new_dsn();
      }

      # See whether there are any connections defined for this mode.  If there's only one
      # connection total, assume the user wants to just use innotop for a single server
      # and don't ask which server to connect to.  Also, if we're monitoring from a file,
      # we just use the first connection.
      if ( !get_connections() ) {
         if ( $file || 1 == scalar keys %connections ) {
            $modes{$config{mode}->{val}}->{connections} = [ keys %connections ];
         }
         else {
            choose_connections();
         }
      }

      # Term::ReadLine might have re-set $OUTPUT_AUTOFLUSH.
      $OUTPUT_AUTOFLUSH = 1;

      # Prune old data
      my $sets = $config{num_status_sets}->{val};
      foreach my $store ( values %vars ) {
         delete @{$store}{ grep { $_ < $clock - $sets } keys %$store };
      }
      %info_gotten = ();

      # Call the subroutine to display this mode.
      $modes{$mode}->{display_sub}->();

      # It may be time to quit now.
      if ( $opts{count} && $clock >= $opts{count} ) {
         finish();
      }

      # Wait for a bit.
      if ( $opts{n} ) {
         sleep($config{interval}->{val});
      }
      else {
         ReadMode('cbreak');
         $char = ReadKey($config{interval}->{val});
         ReadMode('normal');
      }

      # Handle whatever action the key indicates.
      do_key_action();

   }
};
if ( $EVAL_ERROR ) {
   core_dump( $EVAL_ERROR );
}
finish();

# Subroutines {{{1
# Mode functions{{{2
# switch_mode {{{3
sub switch_mode {
   my $mode = shift;
   $config{mode}->{val} = $mode;
}

# Prompting functions {{{2
# prompt_list {{{3
# Prompts the user for a value, given a question, initial value,
# a completion function and a hashref of hints.
sub prompt_list {
   die "Can't call in non-interactive mode" if $opts{n};
   my ( $question, $init, $completion, $hints ) = @_;
   if ( $hints ) {
      # Figure out how wide the table will be
      my $max_name = max(map { length($_) } keys %$hints );
      $max_name ||= 0;
      $max_name +=  3;
      my @meta_rows = create_table2(
               [ sort keys %$hints ],
               { map { $_ => $_ } keys %$hints },
               { map { $_ => trunc($hints->{$_}, $this_term_size[0] - $max_name) } keys %$hints },
               { sep => '  ' });
      if (@meta_rows > 10) {
         # Try to split and stack the meta rows next to each other
         my $split = int(@meta_rows / 2);
         @meta_rows = stack_next(
            [@meta_rows[0..$split - 1]],
            [@meta_rows[$split..$#meta_rows]],
            { pad => ' | '},
         );
      }
      print join( "\n",
         '',
         map { ref $_ ? colored(@$_) : $_ } create_caption('Choose from', @meta_rows), ''),
         "\n";
   }
   $term->Attribs->{completion_function} = $completion;
   my $answer = $term->readline("$question: ", $init);
   $OUTPUT_AUTOFLUSH = 1;
   $answer = '' if !defined($answer);
   $answer =~ s/\s+$//;
   return $answer;
}

# prompt {{{3
# Prints out a prompt and reads from the keyboard, then validates with the
# validation regex until the input is correct.
sub prompt {
   die "Can't call in non-interactive mode" if $opts{n};
   my ( $prompt, $regex, $init, $completion ) = @_;
   my $response;
   my $success = 0;
   do {
      if ( $completion ) {
         $term->Attribs->{completion_function} = $completion;
      }
      $response = $term->readline("$prompt: ", $init);
      if ( $regex && $response !~ m/$regex/ ) {
         print "Invalid response.\n\n";
      }
      else {
         $success = 1;
      }
   } while ( !$success );
   $OUTPUT_AUTOFLUSH = 1;
   $response =~ s/\s+$//;
   return $response;
}

# prompt_noecho {{{3
# Unfortunately, suppressing echo with Term::ReadLine isn't reliable; the user might not
# have that library, or it might not support that feature.
sub prompt_noecho {
   my ( $prompt ) = @_;
   print colored("$prompt: ", 'underline');
   my $response;
   ReadMode('noecho');
   $response = <STDIN>;
   chomp($response);
   ReadMode('normal');
   return $response;
}

# do_key_action {{{3
# Depending on whether a key was read, do something.  Keys have certain
# actions defined in lookup tables.  Each mode may have its own lookup table,
# which trumps the global table -- so keys can be context-sensitive.  The key
# may be read and written in a subroutine, so it's a global.
sub do_key_action {
   if ( defined $char ) {
      my $mode = $config{mode}->{val};
      my $action
         = defined($modes{$mode}->{action_for}->{$char})
         ? $modes{$mode}->{action_for}->{$char}->{action}
         : defined($action_for{$char})
         ? $action_for{$char}->{action}
         : sub{};
      $action->();
   }
}

# pause {{{3
sub pause {
   die "Can't call in non-interactive mode" if $opts{n};
   my $msg = shift;
   print defined($msg) ? "\n$msg" : "\nPress any key to continue";
   ReadMode('cbreak');
   my $char = ReadKey(0);
   ReadMode('normal');
   return $char;
}

# reverse_sort {{{3
sub reverse_sort {
   my $tbl = shift;
   $tbl_meta{$tbl}->{sort_dir} *= -1;
}

# select_cxn {{{3
# Selects connection(s).  If the mode (or argument list) has only one, returns
# it without prompt.
sub select_cxn {
   my ( $prompt, @cxns ) = @_;
   if ( !@cxns ) {
      @cxns = get_connections();
   }
   if ( @cxns == 1 ) {
      return $cxns[0];
   }
   my $choices = prompt_list(
         $prompt,
         $cxns[0],
         sub{ return @cxns },
         { map { $_ => $connections{$_}->{dsn} } @cxns });
   my @result = unique(grep { my $a = $_; grep { $_ eq $a } @cxns } split(/\s+/, $choices));
   return @result;
}

# kill_query {{{3
# Kills a connection, or on new versions, optionally a query but not connection.
sub kill_query {
   my ( $q_or_c ) = @_;

   my $info = choose_thread(
      sub { 1 },
      'Select a thread to kill the ' . $q_or_c,
   );
   return unless $info;
   return unless pause("Kill $info->{id}?") =~ m/y/i;

   eval {
      do_stmt($info->{cxn}, $q_or_c eq 'QUERY' ? 'KILL_QUERY' : 'KILL_CONNECTION', $info->{id} );
   };

   if ( $EVAL_ERROR ) {
      print "\nError: $EVAL_ERROR";
      pause();
   }
}

# set_display_precision {{{3
sub set_display_precision {
   my $dir = shift;
   $config{num_digits}->{val} = min(9, max(0, $config{num_digits}->{val} + $dir));
}

sub toggle_visible_table {
   my ( $mode, $table ) = @_;
   my $visible = $modes{$mode}->{visible_tables};
   if ( grep { $_ eq $table } @$visible ) {
      $modes{$mode}->{visible_tables} = [ grep { $_ ne $table } @$visible ];
   }
   else {
      unshift @$visible, $table;
   }
   $modes{$mode}->{cust}->{visible_tables} = 1;
}

# toggle_filter{{{3
sub toggle_filter {
   my ( $tbl, $filter ) = @_;
   my $filters = $tbl_meta{$tbl}->{filters};
   if ( grep { $_ eq $filter } @$filters ) {
      $tbl_meta{$tbl}->{filters} = [ grep { $_ ne $filter } @$filters ];
   }
   else {
      push @$filters, $filter;
   }
   $tbl_meta{$tbl}->{cust}->{filters} = 1;
}

# toggle_config {{{3
sub toggle_config {
   my ( $key ) = @_;
   $config{$key}->{val} ^= 1;
}

# create_deadlock {{{3
sub create_deadlock {
   $clear_screen_sub->();

   print "This function will deliberately cause a small deadlock, "
      . "clearing deadlock information from the InnoDB monitor.\n\n";

   my $answer = prompt("Are you sure you want to proceed?  Say 'y' if you do");
   return 0 unless $answer eq 'y';

   my ( $cxn ) = select_cxn('Clear on which server? ');
   return unless $cxn && exists($connections{$cxn});

   clear_deadlock($cxn);
}

# deadlock_thread {{{3
sub deadlock_thread {
   my ( $id, $tbl, $cxn ) = @_;

   eval {
      my $dbh = get_new_db_connection($cxn, 1);
      my @stmts = (
         "set transaction isolation level serializable",
         (version_ge($dbh, '4.0.11') ? "start transaction" : 'begin'),
         "select * from $tbl where a = $id",
         "update $tbl set a = $id where a <> $id",
      );

      foreach my $stmt (@stmts[0..2]) {
         $dbh->do($stmt);
      }
      sleep(1 + $id);
      $dbh->do($stmts[-1]);
   };
   if ( $EVAL_ERROR ) {
      if ( $EVAL_ERROR !~ m/Deadlock found/ ) {
         die $EVAL_ERROR;
      }
   }
   exit(0);
}

# Purges unused binlogs on the master, up to but not including the latest log.
# TODO: guess which connections are slaves of a given master.
sub purge_master_logs {
   my @cxns = get_connections();

   get_master_slave_status(@cxns);

   # Toss out the rows that don't have master/slave status...
   my @vars =
      grep { $_ && ($_->{file} || $_->{master_host}) }
      map  { $vars{$_}->{$clock} } @cxns;
   @cxns = map { $_->{cxn} } @vars;

   # Figure out which master to purge ons.
   my @masters = map { $_->{cxn} } grep { $_->{file} } @vars;
   my ( $master ) = select_cxn('Which master?', @masters );
   return unless $master;
   my ($master_status) = grep { $_->{cxn} eq $master } @vars;

   # Figure out the result order (not lexical order) of master logs.
   my @master_logs = get_master_logs($master);
   my $i = 0;
   my %master_logs = map { $_->{log_name} => $i++ } @master_logs;

   # Ask which slave(s) are reading from this master.
   my @slave_status = grep { $_->{master_host} } @vars;
   my @slaves = map { $_->{cxn} } @slave_status;
   @slaves = select_cxn("Which slaves are reading from $master?", @slaves);
   @slave_status = grep { my $item = $_; grep { $item->{cxn} eq $_ } @slaves } @slave_status;
   return unless @slave_status;

   # Find the minimum binary log in use.
   my $min_log = min(map { $master_logs{$_->{master_log_file}} } @slave_status);
   my $log_name = $master_logs[$min_log]->{log_name};

   my $stmt = "PURGE MASTER LOGS TO '$log_name'";
   send_cmd_to_servers($stmt, 0, 'PURGE {MASTER | BINARY} LOGS {TO "log_name" | BEFORE "date"}', [$master]);
}

sub send_cmd_to_servers {
   my ( $cmd, $all, $hint, $cxns ) = @_;
   if ( $all ) {
      @$cxns = get_connections();
   }
   elsif ( !@$cxns ) {
      @$cxns = select_cxn('Which servers?', @$cxns);
   }
   if ( $hint ) {
      print "\nHint: $hint\n";
   }
   $cmd = prompt('Command to send', undef, $cmd);
   foreach my $cxn ( @$cxns ) {
      eval {
         my $sth = do_query($cxn, $cmd);
      };
      if ( $EVAL_ERROR ) {
         print "Error from $cxn: $EVAL_ERROR\n";
      }
      else {
         print "Success on $cxn\n";
      }
   }
   pause();
}

# Display functions {{{2

sub set_s_mode {
   my ( $func ) = @_;
   $clear_screen_sub->();
   $config{S_func}->{val} = $func;
}

# start_S_mode {{{3
sub start_S_mode {
   $clear_screen_sub->();
   switch_mode('S');
}

# display_B {{{3
sub display_B {
   my @display_lines;
   my @cxns = get_connections();
   get_innodb_status(\@cxns);

   my @buffer_pool;
   my @page_statistics;
   my @insert_buffers;
   my @adaptive_hash_index;
   my %rows_for = (
      buffer_pool         => \@buffer_pool,
      page_statistics     => \@page_statistics,
      insert_buffers      => \@insert_buffers,
      adaptive_hash_index => \@adaptive_hash_index,
   );

   my @visible = get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;

   foreach my $cxn ( @cxns ) {
      my $set = $vars{$cxn}->{$clock};
      my $pre = $vars{$cxn}->{$clock-1} || $set;

      if ( $set->{IB_bp_complete} ) {
         if ( $wanted{buffer_pool} ) {
            push @buffer_pool, extract_values($set, $set, $pre, 'buffer_pool');
         }
         if ( $wanted{page_statistics} ) {
            push @page_statistics, extract_values($set, $set, $pre, 'page_statistics');
         }
      }
      if ( $set->{IB_ib_complete} ) {
         if ( $wanted{insert_buffers} ) {
            push @insert_buffers, extract_values(
               $config{status_inc}->{val} ? inc(0, $cxn) : $set, $set, $pre,
               'insert_buffers');
         }
         if ( $wanted{adaptive_hash_index} ) {
            push @adaptive_hash_index, extract_values($set, $set, $pre, 'adaptive_hash_index');
         }
      }
   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   draw_screen(\@display_lines);
}

# display_C {{{3
sub display_C {
   my @display_lines;
   my @cxns = get_connections();
   get_status_info(@cxns);

   my @cmd_summary;
   my %rows_for = (
      cmd_summary => \@cmd_summary,
   );

   my @visible = get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;

   # For now, I'm manually pulling these variables out and pivoting.  Eventually a SQL-ish
   # dialect should let me join a table to a grouped and pivoted table and do this more easily.
   # TODO: make it so.
   my $prefix = qr/^$config{cmd_filter}->{val}/; # TODO: this is a total hack
   my @values;
   my ($total, $last_total) = (0, 0);
   foreach my $cxn ( @cxns ) {
      my $set = $vars{$cxn}->{$clock};
      my $pre = $vars{$cxn}->{$clock-1} || $set;
      foreach my $key ( keys %$set ) {
         next unless $key =~ m/$prefix/i;
         my $val = $set->{$key};
         next unless defined $val && $val =~ m/^\d+$/;
         my $last_val = $val - ($pre->{$key} || 0);
         $total      += $val;
         $last_total += $last_val;
         push @values, {
            name       => $key,
            value      => $val,
            last_value => $last_val,
         };
      }
   }

   # Add aggregation and turn into a real set TODO: total hack
   if ( $wanted{cmd_summary} ) {
      foreach my $value ( @values ) {
         @{$value}{qw(total last_total)} = ($total, $last_total);
         push @cmd_summary, extract_values($value, $value, $value, 'cmd_summary');
      }
   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   draw_screen(\@display_lines);
}

# display_D {{{3
sub display_D {
   my @display_lines;
   my @cxns = get_connections();
   get_innodb_status(\@cxns);

   my @deadlock_transactions;
   my @deadlock_locks;
   my %rows_for = (
      deadlock_transactions => \@deadlock_transactions,
      deadlock_locks        => \@deadlock_locks,
   );

   my @visible = get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;

   foreach my $cxn ( @cxns ) {
      my $innodb_status = $vars{$cxn}->{$clock};
      my $prev_status   = $vars{$cxn}->{$clock-1} || $innodb_status;

      if ( $innodb_status->{IB_dl_timestring} ) {

         my $victim = $innodb_status->{IB_dl_rolled_back} || 0;

         if ( %wanted ) {
            foreach my $txn_id ( keys %{$innodb_status->{IB_dl_txns}} ) {
               my $txn = $innodb_status->{IB_dl_txns}->{$txn_id};
               my $pre = $prev_status->{IB_dl_txns}->{$txn_id} || $txn;

               if ( $wanted{deadlock_transactions} ) {
                  my $hash = extract_values($txn->{tx}, $txn->{tx}, $pre->{tx}, 'deadlock_transactions');
                  $hash->{cxn}        = $cxn;
                  $hash->{dl_txn_num} = $txn_id;
                  $hash->{victim}     = $txn_id == $victim ? 'Yes' : 'No';
                  $hash->{timestring} = $innodb_status->{IB_dl_timestring};
                  $hash->{truncates}  = $innodb_status->{IB_dl_complete} ? 'No' : 'Yes';
                  push @deadlock_transactions, $hash;
               }

               if ( $wanted{deadlock_locks} ) {
                  foreach my $lock ( @{$txn->{locks}} ) {
                     my $hash = extract_values($lock, $lock, $lock, 'deadlock_locks');
                     $hash->{dl_txn_num}      = $txn_id;
                     $hash->{cxn}             = $cxn;
                     $hash->{mysql_thread_id} = $txn->{tx}->{mysql_thread_id};
                     push @deadlock_locks, $hash;
                  }
               }

            }
         }
      }
   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   draw_screen(\@display_lines);
}

# display_F {{{3
sub display_F {
   my @display_lines;
   my ( $cxn ) = get_connections();
   get_innodb_status([$cxn]);
   my $innodb_status = $vars{$cxn}->{$clock};

   if ( $innodb_status->{IB_fk_timestring} ) {

      push @display_lines, 'Reason: ' . $innodb_status->{IB_fk_reason};

      # Display FK errors caused by invalid DML.
      if ( $innodb_status->{IB_fk_txn} ) {
         my $txn = $innodb_status->{IB_fk_txn};
         push @display_lines,
            '',
            "User $txn->{user} from $txn->{hostname}, thread $txn->{mysql_thread_id} was executing:",
            '', no_ctrl_char($txn->{query_text});
      }

      my @fk_table = create_table2(
         $tbl_meta{fk_error}->{visible},
         meta_to_hdr('fk_error'),
         extract_values($innodb_status, $innodb_status, $innodb_status, 'fk_error'),
         { just => '-', sep => '  '});
      push @display_lines, '', @fk_table;

   }
   else {
      push @display_lines, '', 'No foreign key error data.';
   }
   draw_screen(\@display_lines, { raw => 1 } );
}

# display_I {{{3
sub display_I {
   my @display_lines;
   my @cxns = get_connections();
   get_innodb_status(\@cxns);

   my @io_threads;
   my @pending_io;
   my @file_io_misc;
   my @log_statistics;
   my %rows_for = (
      io_threads     => \@io_threads,
      pending_io     => \@pending_io,
      file_io_misc   => \@file_io_misc,
      log_statistics => \@log_statistics,
   );

   my @visible = get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;

   foreach my $cxn ( @cxns ) {
      my $set = $vars{$cxn}->{$clock};
      my $pre = $vars{$cxn}->{$clock-1} || $set;

      if ( $set->{IB_io_complete} ) {
         if ( $wanted{io_threads} ) {
            my $cur_threads = $set->{IB_io_threads};
            my $pre_threads = $pre->{IB_io_threads} || $cur_threads;
            foreach my $key ( sort keys %$cur_threads ) {
               my $cur_thd = $cur_threads->{$key};
               my $pre_thd = $pre_threads->{$key} || $cur_thd;
               my $hash = extract_values($cur_thd, $cur_thd, $pre_thd, 'io_threads');
               $hash->{cxn} = $cxn;
               push @io_threads, $hash;
            }
         }
         if ( $wanted{pending_io} ) {
            push @pending_io, extract_values($set, $set, $pre, 'pending_io');
         }
         if ( $wanted{file_io_misc} ) {
            push @file_io_misc, extract_values(
               $config{status_inc}->{val} ? inc(0, $cxn) : $set,
               $set, $pre, 'file_io_misc');
         }
      }
      if ( $set->{IB_lg_complete} && $wanted{log_statistics} ) {
         push @log_statistics, extract_values($set, $set, $pre, 'log_statistics');
      }
   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   draw_screen(\@display_lines);
}

# display_L {{{3
sub display_L {
   my @display_lines;
   my @cxns = get_connections();
   get_innodb_status(\@cxns);

   my @innodb_locks;
   my %rows_for = (
      innodb_locks => \@innodb_locks,
   );

   my @visible = get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;

   # Get info on locks
   foreach my $cxn ( @cxns ) {
      my $set = $vars{$cxn}->{$clock} or next;
      my $pre = $vars{$cxn}->{$clock-1} || $set;

      if ( $wanted{innodb_locks} && defined $set->{IB_tx_transactions} && @{$set->{IB_tx_transactions}} ) {

         my $cur_txns = $set->{IB_tx_transactions};
         my $pre_txns = $pre->{IB_tx_transactions} || $cur_txns;
         my %cur_txns = map { $_->{mysql_thread_id} => $_ } @$cur_txns;
         my %pre_txns = map { $_->{mysql_thread_id} => $_ } @$pre_txns;
         foreach my $txn ( @$cur_txns ) {
            foreach my $lock ( @{$txn->{locks}} ) {
               my %hash = map { $_ => $txn->{$_} } qw(txn_id mysql_thread_id lock_wait_time active_secs);
               map { $hash{$_} = $lock->{$_} } qw(lock_type space_id page_no n_bits index db table txn_id lock_mode special insert_intention waiting);
               $hash{cxn} = $cxn;
               push @innodb_locks, extract_values(\%hash, \%hash, \%hash, 'innodb_locks');
            }
         }
      }
   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   draw_screen(\@display_lines);
}

# display_M {{{3
sub display_M {
   my @display_lines;
   my @cxns = get_connections();
   get_master_slave_status(@cxns);
   get_status_info(@cxns);

   my @slave_sql_status;
   my @slave_io_status;
   my @master_status;
   my %rows_for = (
      slave_sql_status => \@slave_sql_status,
      slave_io_status  => \@slave_io_status,
      master_status    => \@master_status,
   );

   my @visible = get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;

   foreach my $cxn ( @cxns ) {
      my $set  = $config{status_inc}->{val} ? inc(0, $cxn) : $vars{$cxn}->{$clock};
      my $pre  = $vars{$cxn}->{$clock - 1} || $set;
      if ( $wanted{slave_sql_status} ) {
         push @slave_sql_status, extract_values($set, $set, $pre, 'slave_sql_status');
      }
      if ( $wanted{slave_io_status} ) {
         push @slave_io_status, extract_values($set, $set, $pre, 'slave_io_status');
      }
      if ( $wanted{master_status} ) {
         push @master_status, extract_values($set, $set, $pre, 'master_status');
      }
   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   draw_screen(\@display_lines);
}

# display_O {{{3
sub display_O {
   my @display_lines = ('');
   my @cxns          = get_connections();
   my @open_tables   = get_open_tables(@cxns);
   my @tables = map { extract_values($_, $_, $_, 'open_tables') } @open_tables;
   push @display_lines, set_to_tbl(\@tables, 'open_tables'), get_cxn_errors(@cxns);
   draw_screen(\@display_lines);
}

# display_Q {{{3
sub display_Q {
   my @display_lines;

   my @q_header;
   my @processlist;
   my %rows_for = (
      q_header    => \@q_header,
      processlist => \@processlist,
   );

   my @visible = $opts{n} ? 'processlist' : get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;

   # Get the data
   my @cxns             = get_connections();
   my @full_processlist = get_full_processlist(@cxns);

   # Create header
   if ( $wanted{q_header} ) {
      get_status_info(@cxns);
      foreach my $cxn ( @cxns ) {
         my $set = $vars{$cxn}->{$clock};
         my $pre = $vars{$cxn}->{$clock-1} || $set;
         my $hash = extract_values($set, $set, $pre, 'q_header');
         $hash->{cxn} = $cxn;
         $hash->{when} = 'Total';
         push @q_header, $hash;

         if ( exists $vars{$cxn}->{$clock - 1} ) {
            my $inc = inc(0, $cxn);
            my $hash = extract_values($inc, $set, $pre, 'q_header');
            $hash->{cxn} = $cxn;
            $hash->{when} = 'Now';
            push @q_header, $hash;
         }
      }
   }

   if ( $wanted{processlist} ) {
      # TODO: save prev values
      push @processlist, map { extract_values($_, $_, $_, 'processlist') } @full_processlist;
   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      next unless $wanted{$tbl};
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   # Save queries in global variable for analysis.  The rows in %rows_for have been
   # filtered, etc as a side effect of set_to_tbl(), so they are the same as the rows
   # that get pushed to the screen.
   @current_queries = map {
      my %hash;
      @hash{ qw(cxn id db query secs) } = @{$_}{ qw(cxn mysql_thread_id db info secs) };
      \%hash;
   } @{$rows_for{processlist}};

   draw_screen(\@display_lines);
}

# display_R {{{3
sub display_R {
   my @display_lines;
   my @cxns = get_connections();
   get_innodb_status(\@cxns);

   my @row_operations;
   my @row_operation_misc;
   my @semaphores;
   my @wait_array;
   my %rows_for = (
      row_operations     => \@row_operations,
      row_operation_misc => \@row_operation_misc,
      semaphores         => \@semaphores,
      wait_array         => \@wait_array,
   );

   my @visible = get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;
   my $incvar  = $config{status_inc}->{val};

   foreach my $cxn ( @cxns ) {
      my $set = $vars{$cxn}->{$clock};
      my $pre = $vars{$cxn}->{$clock-1} || $set;
      my $inc; # Only assigned to if wanted

      if ( $set->{IB_ro_complete} ) {
         if ( $wanted{row_operations} ) {
            $inc ||= $incvar ? inc(0, $cxn) : $set;
            push @row_operations, extract_values($inc, $set, $pre, 'row_operations');
         }
         if ( $wanted{row_operation_misc} ) {
            push @row_operation_misc, extract_values($set, $set, $pre, 'row_operation_misc'),
         }
      }

      if ( $set->{IB_sm_complete} && $wanted{semaphores} ) {
         $inc ||= $incvar ? inc(0, $cxn) : $set;
         push @semaphores, extract_values($inc, $set, $pre, 'semaphores');
      }

      if ( $set->{IB_sm_wait_array_size} && $wanted{wait_array} ) {
         foreach my $wait ( @{$set->{IB_sm_waits}} ) {
            my $hash = extract_values($wait, $wait, $wait, 'wait_array');
            $hash->{cxn} = $cxn;
            push @wait_array, $hash;
         }
      }
   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   draw_screen(\@display_lines);
}

# display_T {{{3
sub display_T {
   my @display_lines;

   my @t_header;
   my @innodb_transactions;
   my %rows_for = (
      t_header            => \@t_header,
      innodb_transactions => \@innodb_transactions,
   );

   my @visible = $opts{n} ? 'innodb_transactions' : get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;

   my @cxns = get_connections();

   # If the header is to be shown, buffer pool data is required.
   get_innodb_status( \@cxns, [ $wanted{t_header} ? qw(bp) : () ] );

   foreach my $cxn ( get_connections() ) {
      my $set = $vars{$cxn}->{$clock};
      my $pre = $vars{$cxn}->{$clock-1} || $set;

      next unless $set->{IB_tx_transactions};

      if ( $wanted{t_header} ) {
         my $hash = extract_values($set, $set, $pre, 't_header');
         push @t_header, $hash;
      }

      if ( $wanted{innodb_transactions} ) {
         my $cur_txns = $set->{IB_tx_transactions};
         my $pre_txns = $pre->{IB_tx_transactions} || $cur_txns;
         my %cur_txns = map { $_->{mysql_thread_id} => $_ } @$cur_txns;
         my %pre_txns = map { $_->{mysql_thread_id} => $_ } @$pre_txns;
         foreach my $thd_id ( sort keys %cur_txns ) {
            my $cur_txn = $cur_txns{$thd_id};
            my $pre_txn = $pre_txns{$thd_id} || $cur_txn;
            my $hash    = extract_values($cur_txn, $cur_txn, $pre_txn, 'innodb_transactions');
            $hash->{cxn} = $cxn;
            push @innodb_transactions, $hash;
         }
      }

   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   # Save queries in global variable for analysis.  The rows in %rows_for have been
   # filtered, etc as a side effect of set_to_tbl(), so they are the same as the rows
   # that get pushed to the screen.
   @current_queries = map {
      my %hash;
      @hash{ qw(cxn id db query secs) } = @{$_}{ qw(cxn mysql_thread_id db query_text active_secs) };
      \%hash;
   } @{$rows_for{innodb_transactions}};

   draw_screen(\@display_lines);
}

# display_S {{{3
sub display_S {
   my $fmt  = get_var_set('S_set');
   my $func = $config{S_func}->{val};
   my $inc  = $func eq 'g' || $config{status_inc}->{val};

   # The table's meta-data is generated from the compiled var_set.
   my ( $cols, $visible );
   if ( $tbl_meta{var_status}->{fmt} && $fmt eq $tbl_meta{var_status}->{fmt} ) {
      ( $cols, $visible ) = @{$tbl_meta{var_status}}{qw(cols visible)};
   }
   else {
      ( $cols, $visible ) = compile_select_stmt($fmt);

      # Apply missing values to columns.  Always apply averages across all connections.
      map {
         $_->{agg}   = 'avg';
         $_->{label} = $_->{hdr};
      } values %$cols;

      $tbl_meta{var_status}->{cols}    = $cols;
      $tbl_meta{var_status}->{visible} = $visible;
      $tbl_meta{var_status}->{fmt}     = $fmt;
      map { $tbl_meta{var_status}->{cols}->{$_}->{just} = ''} @$visible;
   }

   my @var_status;
   my %rows_for = (
      var_status => \@var_status,
   );

   my @visible = get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;
   my @cxns    = get_connections();

   get_status_info(@cxns);
   get_innodb_status(\@cxns);

   # Set up whether to pivot and how many sets to extract.
   $tbl_meta{var_status}->{pivot} = $func eq 'v';

   my $num_sets
      = $func eq 'v'
      ? $config{num_status_sets}->{val}
      : 0;
   foreach my $set ( 0 .. $num_sets ) {
      my @rows;
      foreach my $cxn ( @cxns ) {
         my $vars = $inc ? inc($set, $cxn) : $vars{$cxn}->{$clock - $set};
         my $cur  = $vars{$cxn}->{$clock-$set};
         my $pre  = $vars{$cxn}->{$clock-$set-1} || $cur;
         next unless $vars && %$vars;
         my $hash = extract_values($vars, $cur, $pre, 'var_status');
         push @rows, $hash;
      }
      @rows = apply_group_by('var_status', [], @rows);
      push @var_status, @rows;
   }

   # Recompile the sort func. TODO: avoid recompiling at every refresh.
   # Figure out whether the data is all numeric and decide on a sort type.
   # my $cmp
   #   = scalar(
   #      grep { !defined $_ || $_ !~ m/^\d+$/ }
   #      map  { my $col = $_; map { $_->{$col} } @var_status }
   #           $tbl_meta{var_status}->{sort_cols} =~ m/(\w+)/g)
   #   ? 'cmp'
   #   : '<=>';
   $tbl_meta{var_status}->{sort_func} = make_sort_func($tbl_meta{var_status});

   # ################################################################
   # Now there is specific display code based on $config{S_func}
   # ################################################################
   if ( $func =~ m/s|g/ ) {
      my $min_width = 4;

      # Clear the screen if the display width changed.
      if ( @last_term_size && $this_term_size[0] != $last_term_size[0] ) {
         $lines_printed = 0;
         $clear_screen_sub->();
      }

      if ( $func eq 's' ) {
         # Decide how wide columns should be.
         my $num_cols = scalar(@$visible);
         my $width    = $opts{n} ? 0 : max($min_width, int(($this_term_size[0] - $num_cols + 1) / $num_cols));
         my $g_format = $opts{n} ? ( "%s\t" x $num_cols ) : ( "%-${width}s " x $num_cols );

         # Print headers every now and then.  Headers can get really long, so compact them.
         my @hdr = @$visible;
         if ( $opts{n} ) {
            if ( $lines_printed == 0 ) {
               print join("\t", @hdr), "\n";
               $lines_printed++;
            }
         }
         elsif ( $lines_printed == 0 || $lines_printed > $this_term_size[1] - 2 ) {
            @hdr = map { donut(crunch($_, $width), $width) } @hdr;
            print join(' ', map { sprintf( "%${width}s", donut($_, $width)) } @hdr) . "\n";
            $lines_printed = 1;
         }

         # Design a column format for the values.
         my $format
            = $opts{n}
            ? join("\t", map { '%s' } @$visible) . "\n"
            : join(' ',  map { "%${width}s" } @hdr) . "\n";

         foreach my $row ( @var_status ) {
            printf($format, map { defined $_ ? $_ : '' } @{$row}{ @$visible });
            $lines_printed++;
         }
      }
      else { # 'g' mode
         # Design a column format for the values.
         my $num_cols = scalar(@$visible);
         my $width    = $opts{n} ? 0 : int(($this_term_size[0] - $num_cols + 1) / $num_cols);
         my $format   = $opts{n} ? ( "%s\t" x $num_cols ) : ( "%-${width}s " x $num_cols );
         $format      =~ s/\s$/\n/;

         # Print headers every now and then.
         if ( $opts{n} ) {
            if ( $lines_printed == 0 ) {
               print join("\t", @$visible), "\n";
               print join("\t", map { shorten($mvs{$_}) } @$visible), "\n";
            }
         }
         elsif ( $lines_printed == 0 || $lines_printed > $this_term_size[1] - 2 ) {
            printf($format, map { donut(crunch($_, $width), $width) } @$visible);
            printf($format, map { shorten($mvs{$_} || 0) } @$visible);
            $lines_printed = 2;
         }

         # Update the max ever seen, and scale by the max ever seen.
         my $set = $var_status[0];
         foreach my $col ( @$visible ) {
            $set->{$col}  = 1 unless defined $set->{$col} && $set->{$col} =~ m/$num_regex/;
            $set->{$col}  = ($set->{$col} || 1) / ($set->{Uptime_hires} || 1);
            $mvs{$col}    = max($mvs{$col} || 1, $set->{$col});
            $set->{$col} /= $mvs{$col};
         }
         printf($format, map { ( $config{graph_char}->{val} x int( $width * $set->{$_} )) || '.' } @$visible );
         $lines_printed++;

      }
   }
   else { # 'v'
      my $first_table = 0;
      my @display_lines;
      foreach my $tbl ( @visible ) {
         push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
         push @display_lines, get_cxn_errors(@cxns)
            if ( $config{debug}->{val} || !$first_table++ );
      }
      $clear_screen_sub->();
      draw_screen( \@display_lines );
   }
}

# display_explain {{{3
sub display_explain {
   my $info = shift;
   my $cxn   = $info->{cxn};
   my $db    = $info->{db};

   my ( $mods, $query ) = rewrite_for_explain($info->{query});

   my @display_lines;

   if ( $query ) {

      my $part = version_ge($dbhs{$cxn}->{dbh}, '5.1.5') ? 'PARTITIONS' : '';
      $query = "EXPLAIN $part\n" . $query;

      eval {
         if ( $db ) {
            do_query($cxn, "use $db");
         }
         my $sth = do_query($cxn, $query);

         my $res;
         while ( $res = $sth->fetchrow_hashref() ) {
            map { $res->{$_} ||= '' } ( 'partitions', keys %$res);
            my @this_table = create_caption("Sub-Part $res->{id}",
               create_table2(
                  $tbl_meta{explain}->{visible},
                  meta_to_hdr('explain'),
                  extract_values($res, $res, $res, 'explain')));
            @display_lines = stack_next(\@display_lines, \@this_table, { pad => '  ', vsep => 2 });
         }
      };

      if ( $EVAL_ERROR ) {
         push @display_lines,
            '',
            "The query could not be explained.  Only SELECT queries can be "
            . "explained; innotop tries to rewrite certain REPLACE and INSERT queries "
            . "into SELECT, but this doesn't always succeed.";
      }

   }
   else {
      push @display_lines, '', 'The query could not be explained.';
   }

   if ( $mods ) {
      push @display_lines, '', '[This query has been re-written to be explainable]';
   }

   unshift @display_lines, no_ctrl_char($query);
   draw_screen(\@display_lines, { raw => 1 } );
}

# rewrite_for_explain {{{3
sub rewrite_for_explain {
   my $query = shift;

   my $mods = 0;
   my $orig = $query;
   $mods += $query =~ s/^\s*(?:replace|insert).*?select/select/is;
   $mods += $query =~ s/^
      \s*create\s+(?:temporary\s+)?table
      \s+(?:\S+\s+)as\s+select/select/xis;
   $mods += $query =~ s/\s+on\s+duplicate\s+key\s+update.*$//is;
   return ( $mods, $query );
}

# show_optimized_query {{{3
sub show_optimized_query {
   my $info = shift;
   my $cxn   = $info->{cxn};
   my $db    = $info->{db};
   my $meta  = $dbhs{$cxn};

   my @display_lines;

   my ( $mods, $query ) = rewrite_for_explain($info->{query});

   if ( $mods ) {
      push @display_lines, '[This query has been re-written to be explainable]';
   }

   if ( $query ) {
      push @display_lines, no_ctrl_char($info->{query});

      eval {
         if ( $db ) {
            do_query($cxn, "use $db");
         }
         do_query( $cxn, 'EXPLAIN EXTENDED ' . $query ) or die "Can't explain query";
         my $sth = do_query($cxn, 'SHOW WARNINGS');
         my $res = $sth->fetchall_arrayref({});

         if ( $res ) {
            foreach my $result ( @$res ) {
               push @display_lines, 'Note:', no_ctrl_char($result->{message});
            }
         }
         else {
            push @display_lines, '', 'The query optimization could not be generated.';
         }
      };

      if ( $EVAL_ERROR ) {
         push @display_lines, '', "The optimization could not be generated: $EVAL_ERROR";
      }

   }
   else {
      push @display_lines, '', 'The query optimization could not be generated.';
   }

   draw_screen(\@display_lines, { raw => 1 } );
}

# display_help {{{3
sub display_help {
   my $mode = $config{mode}->{val};

   # Get globally mapped keys, then overwrite them with mode-specific ones.
   my %keys = map {
         $_ => $action_for{$_}->{label}
      } keys %action_for;
   foreach my $key ( keys %{$modes{$mode}->{action_for}} ) {
      $keys{$key} = $modes{$mode}->{action_for}->{$key}->{label};
   }
   delete $keys{'?'};

   # Split them into three kinds of keys: MODE keys, action keys, and
   # magic (special character) keys.
   my @modes   = sort grep { m/[A-Z]/   } keys %keys;
   my @actions = sort grep { m/[a-z]/   } keys %keys;
   my @magic   = sort grep { m/[^A-Z]/i } keys %keys;

   my @display_lines = ( '', 'Switch to a different mode:' );

   # Mode keys
   my @all_modes = map { "$_  $modes{$_}->{hdr}" } @modes;
   my @col1 = splice(@all_modes, 0, ceil(@all_modes/3));
   my @col2 = splice(@all_modes, 0, ceil(@all_modes/2));
   my $max1 = max(map {length($_)} @col1);
   my $max2 = max(map {length($_)} @col2);
   while ( @col1 ) {
      push @display_lines, sprintf("   %-${max1}s  %-${max2}s  %s",
         (shift @col1      || ''),
         (shift @col2      || ''),
         (shift @all_modes || ''));
   }

   # Action keys
   my @all_actions = map { "$_  $keys{$_}" } @actions;
   @col1 = splice(@all_actions, 0, ceil(@all_actions/2));
   $max1 = max(map {length($_)} @col1);
   push @display_lines, '', 'Actions:';
   while ( @col1 ) {
      push @display_lines, sprintf("   %-${max1}s  %s",
         (shift @col1        || ''),
         (shift @all_actions || ''));
   }

   # Magic keys
   my @all_magic = map { sprintf('%4s', $action_for{$_}->{key} || $_) . "  $keys{$_}" } @magic;
   @col1 = splice(@all_magic, 0, ceil(@all_magic/2));
   $max1 = max(map {length($_)} @col1);
   push @display_lines, '', 'Other:';
   while ( @col1 ) {
      push @display_lines, sprintf("%-${max1}s%s",
         (shift @col1      || ''),
         (shift @all_magic || ''));
   }

   $clear_screen_sub->();
   draw_screen(\@display_lines, { show_all => 1 } );
   pause();
   $clear_screen_sub->();
}

# show_full_query {{{3
sub show_full_query {
   my $info = shift;
   my @display_lines = no_ctrl_char($info->{query});
   draw_screen(\@display_lines, { raw => 1 });
}

# Formatting functions {{{2

# create_table2 {{{3
# Makes a two-column table, labels on left, data on right.
# Takes refs of @cols, %labels and %data, %user_prefs
sub create_table2 {
   my ( $cols, $labels, $data, $user_prefs ) = @_;
   my @rows;

   if ( @$cols && %$data ) {

      # Override defaults
      my $p = {
         just  => '',
         sep   => ':',
         just1 => '-',
      };
      if ( $user_prefs ) {
         map { $p->{$_} = $user_prefs->{$_} } keys %$user_prefs;
      }

      # Fix undef values
      map { $data->{$_} = '' unless defined $data->{$_} } @$cols;

      # Format the table
      my $max_l = max(map{ length($labels->{$_}) } @$cols);
      my $max_v = max(map{ length($data->{$_}) } @$cols);
      my $format    = "%$p->{just}${max_l}s$p->{sep} %$p->{just1}${max_v}s";
      foreach my $col ( @$cols ) {
         push @rows, sprintf($format, $labels->{$col}, $data->{$col});
      }
   }
   return @rows;
}

# stack_next {{{3
# Stacks one display section next to the other.  Accepts left-hand arrayref,
# right-hand arrayref, and options hashref.  Tries to stack as high as
# possible, so
# aaaaaa
# bbb
# can stack ccc next to the bbb.
# NOTE: this DOES modify its arguments, even though it returns a new array.
sub stack_next {
   my ( $left, $right, $user_prefs ) = @_;
   my @result;

   my $p = {
      pad   => ' ',
      vsep  => 0,
   };
   if ( $user_prefs ) {
      map { $p->{$_} = $user_prefs->{$_} } keys %$user_prefs;
   }

   # Find out how wide the LHS can be and still let the RHS fit next to it.
   my $pad   = $p->{pad};
   my $max_r = max( map { length($_) } @$right) || 0;
   my $max_l = $this_term_size[0] - $max_r - length($pad);

   # Find the minimum row on the LHS that the RHS will fit next to.
   my $i = scalar(@$left) - 1;
   while ( $i >= 0 && length($left->[$i]) <= $max_l ) {
      $i--;
   }
   $i++;
   my $offset = $i;

   if ( $i < scalar(@$left) ) {
      # Find the max width of the section of the LHS against which the RHS
      # will sit.
      my $max_i_in_common = min($i + scalar(@$right) - 1, scalar(@$left) - 1);
      my $max_width = max( map { length($_) } @{$left}[$i..$max_i_in_common]);

      # Append the RHS onto the LHS until one runs out.
      while ( $i < @$left && $i - $offset < @$right ) {
         my $format = "%-${max_width}s$pad%${max_r}s";
         $left->[$i] = sprintf($format, $left->[$i], $right->[$i - $offset]);
         $i++;
      }
      while ( $i - $offset < @$right ) {
         # There is more RHS to push on the end of the array
         push @$left,
            sprintf("%${max_width}s$pad%${max_r}s", ' ', $right->[$i - $offset]);
         $i++;
      }
      push @result, @$left;
   }
   else {
      # There is no room to put them side by side.  Add them below, with
      # a blank line above them if specified.
      push @result, @$left;
      push @result, (' ' x $this_term_size[0]) if $p->{vsep} && @$left;
      push @result, @$right;
   }
   return @result;
}

# create_caption {{{3
sub create_caption {
   my ( $caption, @rows ) = @_;
   if ( @rows ) {

      # Calculate the width of what will be displayed, so it can be centered
      # in that space.  When the thing is wider than the display, center the
      # caption in the display.
      my $width = min($this_term_size[0], max(map { length(ref($_) ? $_->[0] : $_) } @rows));

      my $cap_len = length($caption);

      # It may be narrow enough to pad the sides with underscores and save a
      # line on the screen.
      if ( $cap_len <= $width - 6 ) {
         my $left = int(($width - 2 - $cap_len) / 2);
         unshift @rows,
            ("_" x $left) . " $caption " . ("_" x ($width - $left - $cap_len - 2));
      }

      # The caption is too wide to add underscores on each side.
      else {

         # Color is supported, so we can use terminal underlining.
         if ( $config{color}->{val} ) {
            my $left = int(($width - $cap_len) / 2);
            unshift @rows, [
               (" " x $left) . $caption . (" " x ($width - $left - $cap_len)),
               'underline',
            ];
         }

         # Color is not supported, so we have to add a line underneath to separate the
         # caption from whatever it's captioning.
         else {
            my $left = int(($width - $cap_len) / 2);
            unshift @rows, ('-' x $width);
            unshift @rows, (" " x $left) . $caption . (" " x ($width - $left - $cap_len));
         }

         # The caption is wider than the thing it labels, so we have to pad the
         # thing it labels to a consistent width.
         if ( $cap_len > $width ) {
            @rows = map {
               ref($_)
                  ? [ sprintf('%-' . $cap_len . 's', $_->[0]), $_->[1] ]
                  : sprintf('%-' . $cap_len . 's', $_);
            } @rows;
         }

      }
   }
   return @rows;
}

# create_table {{{3
# Input: an arrayref of columns, hashref of col info, and an arrayref of hashes
# Example: [ 'a', 'b' ]
#          { a => spec, b => spec }
#          [ { a => 1, b => 2}, { a => 3, b => 4 } ]
# The 'spec' is a hashref of hdr => label, just => ('-' or '').  It also supports min and max-widths
# vi the minw and maxw params.
# Output: an array of strings, one per row.
# Example:
# Column One Column Two
# ---------- ----------
# 1          2
# 3          4
sub create_table {
   my ( $cols, $info, $data, $prefs ) = @_;
   $prefs ||= {};
   $prefs->{no_hdr} ||= ($opts{n} && $clock != 1);

   # Truncate rows that will surely be off screen even if this is the only table.
   if ( !$opts{n} && !$prefs->{raw} && !$prefs->{show_all} && $this_term_size[1] < @$data-1 ) {
      $data = [ @$data[0..$this_term_size[1] - 1] ];
   }

   my @rows = ();

   if ( @$cols && %$info ) {

      # Fix undef values, collapse whitespace.
      foreach my $row ( @$data ) {
         map { $row->{$_} = collapse_ws($row->{$_}) } @$cols;
      }

      my $col_sep = $opts{n} ? "\t" : '  ';

      # Find each column's max width.
      my %width_for;
      if ( !$opts{n} ) {
         %width_for = map {
            my $col_name  = $_;
            if ( $info->{$_}->{dec} ) {
               # Align along the decimal point
               my $max_rodp = max(0, map { $_->{$col_name} =~ m/([^\s\d-].*)$/ ? length($1) : 0 } @$data);
               foreach my $row ( @$data ) {
                  my $col = $row->{$col_name};
                  my ( $l, $r ) = $col =~ m/^([\s\d]*)(.*)$/;
                  $row->{$col_name} = sprintf("%s%-${max_rodp}s", $l, $r);
               }
            }
            my $max_width = max( length($info->{$_}->{hdr}), map { length($_->{$col_name}) } @$data);
            if ( $info->{$col_name}->{maxw} ) {
               $max_width = min( $max_width, $info->{$col_name}->{maxw} );
            }
            if ( $info->{$col_name}->{minw} ) {
               $max_width = max( $max_width, $info->{$col_name}->{minw} );
            }
            $col_name => $max_width;
         } @$cols;
      }

      # The table header.
      if ( !$config{hide_hdr}->{val} && !$prefs->{no_hdr} ) {
         push @rows, $opts{n}
            ? join( $col_sep, @$cols )
            : join( $col_sep, map { sprintf( "%-$width_for{$_}s", trunc($info->{$_}->{hdr}, $width_for{$_}) ) } @$cols );
         if ( $config{color}->{val} && $config{header_highlight}->{val} ) {
            push @rows, [ pop @rows, $config{header_highlight}->{val} ];
         }
         elsif ( !$opts{n} ) {
            push @rows, join( $col_sep, map { "-" x $width_for{$_} } @$cols );
         }
      }

      # The table data.
      if ( $opts{n} ) {
         foreach my $item ( @$data ) {
            push @rows, join($col_sep, map { $item->{$_} } @$cols );
         }
      }
      else {
         my $format = join( $col_sep,
            map { "%$info->{$_}->{just}$width_for{$_}s" } @$cols );
         foreach my $item ( @$data ) {
            my $row = sprintf($format, map { trunc($item->{$_}, $width_for{$_}) } @$cols );
            if ( $config{color}->{val} && $item->{_color} ) {
               push @rows, [ $row, $item->{_color} ];
            }
            else {
               push @rows, $row;
            }
         }
      }
   }

   return @rows;
}

# Aggregates a table.  If $group_by is an arrayref of columns, the grouping key
# is the specified columns; otherwise it's just the empty string (e.g.
# everything is grouped as one group).
sub apply_group_by {
   my ( $tbl, $group_by, @rows ) = @_;
   my $meta = $tbl_meta{$tbl};
   my %is_group = map { $_ => 1 } @$group_by;
   my @non_grp  = grep { !$is_group{$_} } keys %{$meta->{cols}};

   my %temp_table;
   foreach my $row ( @rows ) {
      my $group_key
         = @$group_by
         ? '{' . join('}{', map { defined $_ ? $_ : '' } @{$row}{@$group_by}) . '}'
         : '';
      $temp_table{$group_key} ||= [];
      push @{$temp_table{$group_key}}, $row;
   }

   # Crush the rows together...
   my @new_rows;
   foreach my $key ( sort keys %temp_table ) {
      my $group = $temp_table{$key};
      my %new_row;
      @new_row{@$group_by} = @{$group->[0]}{@$group_by};
      foreach my $col ( @non_grp ) {
         my $agg = $meta->{cols}->{$col}->{agg} || 'first';
         $new_row{$col} = $agg_funcs{$agg}->( map { $_->{$col} } @$group );
      }
      push @new_rows, \%new_row;
   }
   return @new_rows;
}

# set_to_tbl {{{3
# Unifies all the work of filtering, sorting etc.  Alters the input.
# TODO: pull all the little pieces out into subroutines and stick events in each of them.
sub set_to_tbl {
   my ( $rows, $tbl ) = @_;
   my $meta = $tbl_meta{$tbl} or die "No such table $tbl in tbl_meta";

   # don't show cxn if there's only one connection being displayed
   my @visible;
   if (scalar @{$modes{$config{mode}->{val}}->{connections}} == 1) {
      map { push @visible, $_ if $_ !~ /^cxn$/ } @{$meta->{visible}};
      delete $$rows[0]{cxn} if defined $$rows[0]{cxn};
   }
   else {
      @visible = @{$meta->{visible}};
   }

   if ( !$meta->{pivot} ) {

      # Hook in event listeners
      foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_filter}} ) {
         $listener->set_to_tbl_pre_filter($rows, $tbl);
      }

      # Apply filters.  Note that if the table is pivoted, filtering and sorting
      # are applied later.
      foreach my $filter ( @{$meta->{filters}} ) {
         eval {
            @$rows = grep { $filters{$filter}->{func}->($_) } @$rows;
         };
         if ( $EVAL_ERROR && $config{debug}->{val} ) {
            die $EVAL_ERROR;
         }
      }

      foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_sort}} ) {
         $listener->set_to_tbl_pre_sort($rows, $tbl);
      }

      # Sort.  Note that if the table is pivoted, sorting might have the wrong
      # columns and it could crash.  This will only be an issue if it's possible
      # to toggle pivoting on and off, which it's not at the moment.
      if ( @$rows && $meta->{sort_func} && !$meta->{aggregate} ) {
         if ( $meta->{sort_dir} > 0 ) {
            @$rows = $meta->{sort_func}->( @$rows );
         }
         else {
            @$rows = reverse $meta->{sort_func}->( @$rows );
         }
      }

   }

   # Stop altering arguments now.
   my @rows = @$rows;

   foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_group}} ) {
      $listener->set_to_tbl_pre_group(\@rows, $tbl);
   }

   # Apply group-by.
   if ( $meta->{aggregate} ) {
      @rows = apply_group_by($tbl, $meta->{group_by}, @rows);

      # Sort.  Note that if the table is pivoted, sorting might have the wrong
      # columns and it could crash.  This will only be an issue if it's possible
      # to toggle pivoting on and off, which it's not at the moment.
      if ( @rows && $meta->{sort_func} ) {
         if ( $meta->{sort_dir} > 0 ) {
            @rows = $meta->{sort_func}->( @rows );
         }
         else {
            @rows = reverse $meta->{sort_func}->( @rows );
         }
      }

   }

   foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_colorize}} ) {
      $listener->set_to_tbl_pre_colorize(\@rows, $tbl);
   }

   if ( !$meta->{pivot} ) {
      # Colorize.  Adds a _color column to rows.
      if ( @rows && $meta->{color_func} ) {
         eval {
            foreach my $row ( @rows ) {
               $row->{_color} = $meta->{color_func}->($row);
            }
         };
         if ( $EVAL_ERROR ) {
            pause($EVAL_ERROR);
         }
      }
   }

   foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_transform}} ) {
      $listener->set_to_tbl_pre_transform(\@rows, $tbl);
   }

   # Apply_transformations.
   if ( @rows ) {
      my $cols = $meta->{cols};
      foreach my $col ( keys %{$rows->[0]} ) {
         # Don't auto-vivify $tbl_meta{tbl}-{cols}->{_color}->{trans}
         next if $col eq '_color';
         foreach my $trans ( @{$cols->{$col}->{trans}} ) {
            map { $_->{$col} = $trans_funcs{$trans}->($_->{$col}) } @rows;
         }
      }
   }

   my ($fmt_cols, $fmt_meta);

   # Pivot.
   if ( $meta->{pivot} ) {

      foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_pivot}} ) {
         $listener->set_to_tbl_pre_pivot(\@rows, $tbl);
      }

      my @vars = @{$meta->{visible}};
      my @tmp  = map { { name => $_ } } @vars;
      my @cols = 'name';
      foreach my $i ( 0..@$rows-1 ) {
         my $col = "set_$i";
         push @cols, $col;
         foreach my $j ( 0..@vars-1 ) {
            $tmp[$j]->{$col} = $rows[$i]->{$vars[$j]};
         }
      }
      $fmt_meta = { map { $_ => { hdr => $_, just => '-' } } @cols };
      $fmt_cols = \@cols;
      @rows = @tmp;

      # Hook in event listeners
      foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_filter}} ) {
         $listener->set_to_tbl_pre_filter($rows, $tbl);
      }

      # Apply filters.
      foreach my $filter ( @{$meta->{filters}} ) {
         eval {
            @rows = grep { $filters{$filter}->{func}->($_) } @rows;
         };
         if ( $EVAL_ERROR && $config{debug}->{val} ) {
            die $EVAL_ERROR;
         }
      }

      foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_sort}} ) {
         $listener->set_to_tbl_pre_sort($rows, $tbl);
      }

      # Sort.
      if ( @rows && $meta->{sort_func} ) {
         if ( $meta->{sort_dir} > 0 ) {
            @rows = $meta->{sort_func}->( @rows );
         }
         else {
            @rows = reverse $meta->{sort_func}->( @rows );
         }
      }

   }
   else {
      # If the table isn't pivoted, just show all columns that are supposed to
      # be shown; but eliminate aggonly columns if the table isn't aggregated.
      my $aggregated = $meta->{aggregate};
      $fmt_cols = [ grep { $aggregated || !$meta->{cols}->{$_}->{aggonly} } @visible ];
      $fmt_meta = { map  { $_ => $meta->{cols}->{$_}                      } @$fmt_cols };

      # If the table is aggregated, re-order the group_by columns to the left of
      # the display.
      if ( $aggregated ) {
         my %is_group = map { $_ => 1 } @{$meta->{group_by}};
         $fmt_cols = [ @{$meta->{group_by}}, grep { !$is_group{$_} } @$fmt_cols ];
      }
   }

   foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_create}} ) {
      $listener->set_to_tbl_pre_create(\@rows, $tbl);
   }

   @rows = create_table( $fmt_cols, $fmt_meta, \@rows);
   if ( !$meta->{hide_caption} && !$opts{n} && $config{display_table_captions}->{val} ) {
      @rows = create_caption($meta->{capt}, @rows)
   }

   foreach my $listener ( @{$event_listener_for{set_to_tbl_post_create}} ) {
      $listener->set_to_tbl_post_create(\@rows, $tbl);
   }

   return @rows;
}

# meta_to_hdr {{{3
sub meta_to_hdr {
   my $tbl = shift;
   my $meta = $tbl_meta{$tbl};
   my %labels = map { $_ => $meta->{cols}->{$_}->{hdr} } @{$meta->{visible}};
   return \%labels;
}

# commify {{{3
# From perlfaq5: add commas.
sub commify {
   my ( $num ) = @_;
   $num = 0 unless defined $num;
   $num =~ s/(^[-+]?\d+?(?=(?>(?:\d{3})+)(?!\d))|\G\d{3}(?=\d))/$1,/g;
   return $num;
}

# set_precision {{{3
# Trim to desired precision.
sub set_precision {
   my ( $num, $precision ) = @_;
   $precision = $config{num_digits}->{val} if !defined $precision;
   sprintf("%.${precision}f", $num);
}

# percent {{{3
# Convert to percent
sub percent {
   my ( $num ) = @_;
   $num = 0 unless defined $num;
   my $digits = $config{num_digits}->{val};
   return sprintf("%.${digits}f", $num * 100)
      . ($config{show_percent}->{val} ? '%' : '');
}

# shorten {{{3
sub shorten {
   my ( $num, $opts ) = @_;

   return $num if !defined($num) || $opts{n} || $num !~ m/$num_regex/;

   $opts ||= {};
   my $pad = defined $opts->{pad} ? $opts->{pad} : '';
   my $num_digits = defined $opts->{num_digits}
      ? $opts->{num_digits}
      : $config{num_digits}->{val};
   my $force = defined $opts->{force};

   my $n = 0;
   while ( $num >= 1_024 ) {
      $num /= 1_024;
      ++$n;
   }
   return sprintf(
      $num =~ m/\./ || $n || $force
         ? "%.${num_digits}f%s"
         : '%d',
      $num, ($pad,'k','M','G', 'T')[$n]);

}

# Utility functions {{{2
# unique {{{3
sub unique {
   my %seen;
   return grep { !$seen{$_}++ } @_;
}

# make_color_func {{{3
sub make_color_func {
   my ( $tbl ) = @_;
   my @criteria;
   foreach my $spec ( @{$tbl->{colors}} ) {
      next unless exists $comp_ops{$spec->{op}};
      my $val = $spec->{op} =~ m/^(?:eq|ne|le|ge|lt|gt)$/ ? "'$spec->{arg}'"
              : $spec->{op} =~ m/^(?:=~|!~)$/             ? "m/" . quotemeta($spec->{arg}) . "/"
              :                                             $spec->{arg};
      push @criteria,
         "( defined \$set->{$spec->{col}} && \$set->{$spec->{col}} $spec->{op} $val ) { return '$spec->{color}'; }";
   }
   return undef unless @criteria;
   my $sub = eval 'sub { my ( $set ) = @_; if ' . join(" elsif ", @criteria) . '}';
   die if $EVAL_ERROR;
   return $sub;
}

# make_sort_func {{{3
# Gets a list of sort columns from the table, like "+cxn -time" and returns a
# subroutine that will sort that way.
sub make_sort_func {
   my ( $tbl ) = @_;
   my @criteria;

   # Pivoted tables can be sorted by 'name' and set_x columns; others must be
   # sorted by existing columns.  TODO: this will crash if you toggle between
   # pivoted and nonpivoted.  I have several other 'crash' notes about this if
   # this ever becomes possible.

   if ( $tbl->{pivot} ) {
      # Sort type is not really possible on pivoted columns, because a 'column'
      # contains data from an entire non-pivoted row, so there could be a mix of
      # numeric and non-numeric data.  Thus everything has to be 'cmp' type.
      foreach my $col ( split(/\s+/, $tbl->{sort_cols} ) ) {
         next unless $col;
         my ( $dir, $name ) = $col =~ m/([+-])?(\w+)$/;
         next unless $name && $name =~ m/^(?:name|set_\d+)$/;
         $dir ||= '+';
         my $op = 'cmp';
         my $df = "''";
         push @criteria,
            $dir eq '+'
            ? "(\$a->{$name} || $df) $op (\$b->{$name} || $df)"
            : "(\$b->{$name} || $df) $op (\$a->{$name} || $df)";
      }
   }
   else {
      foreach my $col ( split(/\s+/, $tbl->{sort_cols} ) ) {
         next unless $col;
         my ( $dir, $name ) = $col =~ m/([+-])?(\w+)$/;
         next unless $name && $tbl->{cols}->{$name};
         $dir ||= '+';
         my $op = $tbl->{cols}->{$name}->{num} ? "<=>" : "cmp";
         my $df = $tbl->{cols}->{$name}->{num} ? "0"   : "''";
         push @criteria,
            $dir eq '+'
            ? "(\$a->{$name} || $df) $op (\$b->{$name} || $df)"
            : "(\$b->{$name} || $df) $op (\$a->{$name} || $df)";
      }
   }
   return sub { return @_ } unless @criteria;
   my $sub = eval 'sub { sort {' . join("||", @criteria) . '} @_; }';
   die if $EVAL_ERROR;
   return $sub;
}

# trunc {{{3
# Shortens text to specified length.
sub trunc {
   my ( $text, $len ) = @_;
   if ( length($text) <= $len ) {
      return $text;
   }
   return substr($text, 0, $len);
}

# donut {{{3
# Takes out the middle of text to shorten it.
sub donut {
   my ( $text, $len ) = @_;
   return $text if length($text) <= $len;
   my $max = length($text) - $len;
   my $min = $max - 1;

   # Try to remove a single "word" from somewhere in the center
   if ( $text =~ s/_[^_]{$min,$max}_/_/ ) {
      return $text;
   }

   # Prefer removing the end of a "word"
   if ( $text =~ s/([^_]+)[^_]{$max}_/$1_/ ) {
      return $text;
   }

   $text = substr($text, 0, int($len/2))
         . "_"
         . substr($text, int($len/2) + $max + 1);
   return $text;
}

# crunch {{{3
# Removes vowels and compacts repeated letters to shorten text.
sub crunch {
   my ( $text, $len ) = @_;
   return $text if $len && length($text) <= $len;
   $text =~ s/^IB_\w\w_//;
   $text =~ s/(?<![_ ])[aeiou]//g;
   $text =~ s/(.)\1+/$1/g;
   return $text;
}

# collapse_ws {{{3
# Collapses all whitespace to a single space.
sub collapse_ws {
   my ( $text ) = @_;
   return '' unless defined $text;
   $text =~ s/\s+/ /g;
   return $text;
}

# Strips out non-printable characters within fields, which freak terminals out.
sub no_ctrl_char {
   my ( $text ) = @_;
   return '' unless defined $text;
   my $charset = $config{charset}->{val};
   if ( $charset && $charset eq 'unicode' ) {
      $text =~ s/
         ("(?:(?!(?<!\\)").)*"  # Double-quoted string
         |'(?:(?!(?<!\\)').)*') # Or single-quoted string
         /$1 =~ m#\p{IsC}# ? "[BINARY]" : $1/egx;
   }
   elsif ( $charset && $charset eq 'none' ) {
      $text =~ s/
         ("(?:(?!(?<!\\)").)*"
         |'(?:(?!(?<!\\)').)*')
         /[TEXT]/gx;
   }
   else { # The default is 'ascii'
      $text =~ s/
         ("(?:(?!(?<!\\)").)*"
         |'(?:(?!(?<!\\)').)*')
         /$1 =~ m#[^\040-\176]# ? "[BINARY]" : $1/egx;
   }
   return $text;
}

# word_wrap {{{3
# Wraps text at word boundaries so it fits the screen.
sub word_wrap {
   my ( $text, $width) = @_;
   $width ||= $this_term_size[0];
   $text =~ s/(.{0,$width})(?:\s+|$)/$1\n/g;
   $text =~ s/ +$//mg;
   return $text;
}

# draw_screen {{{3
# Prints lines to the screen.  The first argument is an arrayref.  Each
# element of the array is either a string or an arrayref.  If it's a string it
# just gets printed.  If it's an arrayref, the first element is the string to
# print, and the second is args to colored().
sub draw_screen {
   my ( $display_lines, $prefs ) = @_;
   if ( !$opts{n} && $config{show_statusbar}->{val} ) {
      unshift @$display_lines, create_statusbar();
   }

   foreach my $listener ( @{$event_listener_for{draw_screen}} ) {
      $listener->draw_screen($display_lines);
   }

   $clear_screen_sub->()
      if $prefs->{clear} || !$modes{$config{mode}->{val}}->{no_clear_screen};
   if ( $opts{n} || $prefs->{raw} ) {
      my $num_lines = 0;
      print join("\n",
         map {
            $num_lines++;
            ref $_
               ? colored($_->[0], $_->[1])
               : $_;
         }
         grep { !$opts{n} || $_ } # Suppress empty lines
         @$display_lines);
      if ( $opts{n} && $num_lines ) {
         print "\n";
      }
   }
   else {
      my $max_lines = $prefs->{show_all}
         ? scalar(@$display_lines)- 1
         : min(scalar(@$display_lines), $this_term_size[1]);
      print join("\n",
         map {
            ref $_
               ? colored(substr($_->[0], 0, $this_term_size[0]), $_->[1])
               : substr($_, 0, $this_term_size[0]);
         } @$display_lines[0..$max_lines - 1]);
   }
}

# secs_to_time {{{3
sub secs_to_time {
   my ( $secs, $fmt ) = @_;
   $secs ||= 0;
   return '00:00' unless $secs;

   # Decide what format to use, if not given
   $fmt ||= $secs >= 86_400 ? 'd'
          : $secs >= 3_600  ? 'h'
          :                   'm';

   return
      $fmt eq 'd' ? sprintf(
         "%d+%02d:%02d:%02d",
         int($secs / 86_400),
         int(($secs % 86_400) / 3_600),
         int(($secs % 3_600) / 60),
         $secs % 60)
      : $fmt eq 'h' ? sprintf(
         "%02d:%02d:%02d",
         int(($secs % 86_400) / 3_600),
         int(($secs % 3_600) / 60),
         $secs % 60)
      : sprintf(
         "%02d:%02d",
         int(($secs % 3_600) / 60),
         $secs % 60);
}

# dulint_to_int {{{3
# Takes a number that InnoDB formats as two ulint integers, like transaction IDs
# and such, and turns it into a single integer
sub dulint_to_int {
   my $num = shift;
   return 0 unless $num;
   my ( $high, $low ) = $num =~ m/^(\d+) (\d+)$/;
   return $low unless $high;
   return $low + ( $high * $MAX_ULONG );
}

# create_statusbar {{{3
sub create_statusbar {
   my $mode = $config{mode}->{val};
   my @cxns = sort { $a cmp $b } get_connections();

   my $modeline        = ( $config{readonly}->{val} ? '[RO] ' : '' )
                         . $modes{$mode}->{hdr} . " (? for help)";
   my $mode_width      = length($modeline);
   my $remaining_width = $this_term_size[0] - $mode_width - 1;
   my $result;

   # The thingie in top-right that says what we're monitoring.
   my $cxn = '';

   if ( 1 == @cxns && $dbhs{$cxns[0]} && $dbhs{$cxns[0]}->{dbh} ) {
      $cxn = $dbhs{$cxns[0]}->{dbh}->{mysql_serverinfo} || '';
   }
   else {
      if ( $modes{$mode}->{server_group} ) {
         $cxn = "Servers: " . $modes{$mode}->{server_group};
         my $err_count = grep { $dbhs{$_} && $dbhs{$_}->{err_count} } @cxns;
         if ( $err_count ) {
            $cxn .= "(" . ( scalar(@cxns) - $err_count ) . "/" . scalar(@cxns) . ")";
         }
      }
      else {
         $cxn = join(' ', map { ($dbhs{$_}->{err_count} ? '!' : '') . $_ }
            grep { $dbhs{$_} } @cxns);
      }
   }

   if ( 1 == @cxns ) {
      get_driver_status(@cxns);
      my $vars = $vars{$cxns[0]}->{$clock};
      my $inc  = inc(0, $cxns[0]);

      # Format server uptime human-readably, calculate QPS...
      my $uptime = secs_to_time( $vars->{Uptime_hires} );
      my $qps    = ($inc->{Questions}||0) / ($inc->{Uptime_hires}||1);
      my $ibinfo = '';

      if ( exists $vars->{IB_last_secs} ) {
         $ibinfo .= "InnoDB $vars->{IB_last_secs}s ";
         if ( $vars->{IB_got_all} ) {
            if ( ($mode eq 'T' || $mode eq 'W')
                  && $vars->{IB_tx_is_truncated} ) {
               $ibinfo .= ':^|';
            }
            else {
               $ibinfo .= ':-)';
            }
         }
         else {
            $ibinfo .= ':-(';
         }
      }
      $result = sprintf(
         "%-${mode_width}s %${remaining_width}s",
         $modeline,
         join(', ', grep { $_ } (
            $cxns[0],
            $uptime,
            $ibinfo,
            shorten($qps) . " QPS",
            ($vars->{Threads} || 0) . "/" . ($vars->{Threads_running} || 0) . "/" . ($vars->{Threads_cached} || 0) . " con/run/cac thds",
            $cxn)));
   }
   else {
      $result = sprintf(
         "%-${mode_width}s %${remaining_width}s",
         $modeline,
         $cxn);
   }

   return $config{color}->{val} ? [ $result, 'bold reverse' ] : $result;
}

# Database connections {{{3
sub add_new_dsn {
   my ( $name, $dsn, $dl_table, $have_user, $user, $have_pass, $pass, $savepass ) = @_;

   if ( defined $name ) {
      $name =~ s/[\s:;]//g;
   }

   if ( !$name ) {
      print word_wrap("Choose a name for the connection.  It cannot contain "
         . "whitespace, colons or semicolons."), "\n\n";
      do {
         $name = prompt("Enter a name");
         $name =~ s/[\s:;]//g;
      } until ( $name );
   }

   if ( !$dsn ) {
      do {
         $clear_screen_sub->();
         print "Typical DSN strings look like\n   DBI:mysql:;host=hostname;port=port\n"
            . "The db and port are optional and can usually be omitted.\n"
            . "If you specify 'mysql_read_default_group=mysql' many options can be read\n"
            . "from your mysql options files (~/.my.cnf, /etc/my.cnf).\n\n";
         $dsn = prompt("Enter a DSN string", undef, "DBI:mysql:;mysql_read_default_group=mysql;host=$name");
      } until ( $dsn );
   }
   if ( !$dl_table ) {
      $clear_screen_sub->();
      my $dl_table = prompt("Optional: enter a table (must not exist) to use when resetting InnoDB deadlock information",
         undef, 'test.innotop_dl');
   }

   $connections{$name} = {
      dsn       => $dsn,
      dl_table  => $dl_table,
      have_user => $have_user,
      user      => $user,
      have_pass => $have_pass,
      pass      => $pass,
      savepass  => $savepass
   };
}

sub add_new_server_group {
   my ( $name ) = @_;

   if ( defined $name ) {
      $name =~ s/[\s:;]//g;
   }

   if ( !$name ) {
      print word_wrap("Choose a name for the group.  It cannot contain "
         . "whitespace, colons or semicolons."), "\n\n";
      do {
         $name = prompt("Enter a name");
         $name =~ s/[\s:;]//g;
      } until ( $name );
   }

   my @cxns;
   do {
      $clear_screen_sub->();
      @cxns = select_cxn("Choose servers for $name", keys %connections);
   } until ( @cxns );

   $server_groups{$name} = \@cxns;
   return $name;
}

sub get_var_set {
   my ( $name ) = @_;
   while ( !$name || !exists($var_sets{$config{$name}->{val}}) ) {
      $name = choose_var_set($name);
   }
   return $var_sets{$config{$name}->{val}}->{text};
}

sub add_new_var_set {
   my ( $name ) = @_;

   if ( defined $name ) {
      $name =~ s/\W//g;
   }

   if ( !$name ) {
      do {
         $name = prompt("Enter a name");
         $name =~ s/\W//g;
      } until ( $name );
   }

   my $variables;
   do {
      $clear_screen_sub->();
      $variables = prompt("Enter variables for $name", undef );
   } until ( $variables );

   $var_sets{$name} = { text => $variables, user => 1 };
}

sub next_server {
   my $mode     = $config{mode}->{val};
   my @cxns     = sort keys %connections;
   my ($cur)    = get_connections($mode);
   $cur         ||= $cxns[0];
   my $pos      = grep { $_ lt $cur } @cxns;
   my $newpos   = ($pos + 1) % @cxns;
   $modes{$mode}->{server_group} = '';
   $modes{$mode}->{connections} = [ $cxns[$newpos] ];
   $clear_screen_sub->();
}

sub next_server_group {
   my $mode = shift || $config{mode}->{val};
   my @grps = sort keys %server_groups;
   my $curr = $modes{$mode}->{server_group};

   return unless @grps;

   if ( $curr ) {
      # Find the current group's position.
      my $pos = 0;
      while ( $curr ne $grps[$pos] ) {
         $pos++;
      }
      $modes{$mode}->{server_group} = $grps[ ($pos + 1) % @grps ];
   }
   else {
      $modes{$mode}->{server_group} = $grps[0];
   }
}

# Get a list of connection names used in this mode.
sub get_connections {
   if ( $file ) {
      return qw(file);
   }
   my $mode = shift || $config{mode}->{val};
   my @connections = $modes{$mode}->{server_group}
      ? @{$server_groups{$modes{$mode}->{server_group}}}
      : @{$modes{$mode}->{connections}};
   if ( $modes{$mode}->{one_connection} ) {
      @connections = @connections ? $connections[0] : ();
   }
   return unique(@connections);
}

# Get a list of tables used in this mode.  If innotop is running non-interactively, just use the first.
sub get_visible_tables {
   my $mode = shift || $config{mode}->{val};
   my @tbls = @{$modes{$mode}->{visible_tables}};
   if ( $opts{n} ) {
      return $tbls[0];
   }
   else {
      return @tbls;
   }
}

# Choose from among available connections or server groups.
# If the mode has a server set in use, prefers that instead.
sub choose_connections {
   $clear_screen_sub->();
   my $mode    = $config{mode}->{val};
   my $meta    =  { map { $_ => $connections{$_}->{dsn} } keys %connections };
   foreach my $group ( keys %server_groups ) {
      $meta->{"#$group"} = join(' ', @{$server_groups{$group}});
   }

   my $choices = prompt_list("Choose connections or a group for $mode mode",
      undef, sub { return keys %$meta }, $meta);

   my @choices = unique(grep { $_ } split(/\s+/, $choices));
   if ( @choices ) {
      if ( $choices[0] =~ s/^#// && exists $server_groups{$choices[0]} ) {
         $modes{$mode}->{server_group} = $choices[0];
      }
      else {
         $modes{$mode}->{connections} = [ grep { exists $connections{$_} } @choices ];
      }
   }
}

# Accepts a DB connection name and the name of a prepared query (e.g. status, kill).
# Also a list of params for the prepared query.  This allows not storing prepared
# statements globally.  Returns a $sth that's been executed.
# ERROR-HANDLING SEMANTICS: if the statement throws an error, propagate, but if the
# connection has gone away or can't connect, DO NOT.  Just return undef.
sub do_stmt {
   my ( $cxn, $stmt_name, @args ) = @_;

   return undef if $file;

   # Test if the cxn should not even be tried
   return undef if $dbhs{$cxn}
      && $dbhs{$cxn}->{err_count} 
      && ( !$dbhs{$cxn}->{dbh} || !$dbhs{$cxn}->{dbh}->{Active} || $dbhs{$cxn}->{mode} eq $config{mode}->{val} )
      && $dbhs{$cxn}->{wake_up} > $clock;

   my $sth;
   my $retries = 1;
   my $success = 0;
   TRY:
   while ( $retries-- >= 0 && !$success ) {

      eval {
         my $dbh = connect_to_db($cxn);

         # If the prepared query doesn't exist, make it.
         if ( !exists $dbhs{$cxn}->{stmts}->{$stmt_name} ) {
            $dbhs{$cxn}->{stmts}->{$stmt_name} = $stmt_maker_for{$stmt_name}->($dbh);
         }

         $sth = $dbhs{$cxn}->{stmts}->{$stmt_name};
         if ( $sth ) {
            $sth->execute(@args);
         }
         $success = 1;
      };
      if ( $EVAL_ERROR ) {
         if ( $EVAL_ERROR =~ m/$nonfatal_errs/ ) {
            handle_cxn_error($cxn, $EVAL_ERROR);
         }
         else {
            die "$cxn $stmt_name: $EVAL_ERROR";
         }
         if ( $retries < 0 ) {
            $sth = undef;
         }
      }
   }

   if ( $sth && $sth->{NUM_OF_FIELDS} ) {
      sleep($stmt_sleep_time_for{$stmt_name}) if $stmt_sleep_time_for{$stmt_name};
      return $sth;
   }
}

# Keeps track of error count, sleep times till retries, etc etc.
# When there's an error we retry the connection every so often, increasing in
# Fibonacci series to prevent too much banging on the server.
sub handle_cxn_error {
   my ( $cxn, $err ) = @_;
   my $meta = $dbhs{$cxn};
   $meta->{err_count}++;

   # This is used so errors that have to do with permissions needed by the current
   # mode will get displayed as long as we're in this mode, but get ignored if the
   # mode changes.
   $meta->{mode} = $config{mode}->{val};

   # Strip garbage from the error text if possible.
   $err =~ s/\s+/ /g;
   if ( $err =~ m/failed: (.*?) at \S*innotop line/ ) {
      $err = $1;
   }

   $meta->{last_err}   = $err;
   my $sleep_time      = $meta->{this_sleep} + $meta->{prev_sleep};
   $meta->{prev_sleep} = $meta->{this_sleep};
   $meta->{this_sleep} = $sleep_time;
   $meta->{wake_up}    = $clock + $sleep_time;
   if ( $config{show_cxn_errors}->{val} ) {
      print STDERR "Error at tick $clock $cxn $err" if $config{debug}->{val};
   }
}

# Accepts a DB connection name and a (string) query.  Returns a $sth that's been
# executed.
sub do_query {
   my ( $cxn, $query ) = @_;

   return undef if $file;

   # Test if the cxn should not even be tried
   return undef if $dbhs{$cxn}
      && $dbhs{$cxn}->{err_count} 
      && ( !$dbhs{$cxn}->{dbh} || !$dbhs{$cxn}->{dbh}->{Active} || $dbhs{$cxn}->{mode} eq $config{mode}->{val} )
      && $dbhs{$cxn}->{wake_up} > $clock;

   my $sth;
   my $retries = 1;
   my $success = 0;
   TRY:
   while ( $retries-- >= 0 && !$success ) {

      eval {
         my $dbh = connect_to_db($cxn);

         $sth = $dbh->prepare($query);
         $sth->execute();
         $success = 1;
      };
      if ( $EVAL_ERROR ) {
         if ( $EVAL_ERROR =~ m/$nonfatal_errs/ ) {
            handle_cxn_error($cxn, $EVAL_ERROR);
         }
         else {
            die $EVAL_ERROR;
         }
         if ( $retries < 0 ) {
            $sth = undef;
         }
      }
   }
 
   return $sth;
}

sub get_uptime {
   my ( $cxn ) = @_;
   $dbhs{$cxn}->{start_time} ||= time();
   # Avoid dividing by zero
   return (time() - $dbhs{$cxn}->{start_time}) || .001;
}

sub connect_to_db {
   my ( $cxn ) = @_;

   $dbhs{$cxn} ||= {
      stmts      => {},  # bucket for prepared statements.
      prev_sleep => 0,
      this_sleep => 1,
      wake_up    => 0,
      start_time => 0,
      dbh        => undef,
   };
   my $href = $dbhs{$cxn};

   if ( !$href->{dbh} || ref($href->{dbh}) !~ m/DBI/ || !$href->{dbh}->ping ) {
      my $dbh = get_new_db_connection($cxn);
      @{$href}{qw(dbh err_count wake_up this_sleep start_time prev_sleep)}
               = ($dbh, 0, 0, 1, 0, 0);

      # Derive and store the server's start time in hi-res
      my $uptime = $dbh->selectrow_hashref("show status like 'Uptime'")->{value};
      $href->{start_time} = time() - $uptime;

      # Set timeouts so an unused connection stays alive.
      # For example, a connection might be used in Q mode but idle in T mode.
      if ( version_ge($dbh, '4.0.3')) {
         my $timeout = $config{cxn_timeout}->{val};
         $dbh->do("set session wait_timeout=$timeout, interactive_timeout=$timeout");
      }
   }
   return $href->{dbh};
}

# Compares versions like 5.0.27 and 4.1.15-standard-log
sub version_ge {
   my ( $dbh, $target ) = @_;
   my $version = sprintf('%03d%03d%03d', $dbh->{mysql_serverinfo} =~ m/(\d+)/g);
   return $version ge sprintf('%03d%03d%03d', $target =~ m/(\d+)/g);
}

# Extracts status values that can be gleaned from the DBD driver without doing a whole query.
sub get_driver_status {
   my @cxns = @_;
   if ( !$info_gotten{driver_status}++ ) {
      foreach my $cxn ( @cxns ) {
         next unless $dbhs{$cxn} && $dbhs{$cxn}->{dbh} && $dbhs{$cxn}->{dbh}->{Active};
         $vars{$cxn}->{$clock} ||= {};
         my $vars = $vars{$cxn}->{$clock};
         my %res = map {  $_ =~ s/ +/_/g; $_ } $dbhs{$cxn}->{dbh}->{mysql_stat} =~ m/(\w[^:]+): ([\d\.]+)/g;
         map { $vars->{$_} ||= $res{$_} } keys %res;
         $vars->{Uptime_hires} ||= get_uptime($cxn);
         $vars->{cxn} = $cxn;
      }
   }
}

sub get_new_db_connection {
   my ( $connection, $destroy ) = @_;
   if ( $file ) {
      die "You can't connect to a MySQL server while monitoring a file.  This is probably a bug.";
   }

   my $dsn = $connections{$connection}
      or die "No connection named '$connection' is defined in your configuration";

   # don't ask for a username if mysql_read_default_group=client is in the DSN
   if ( !defined $dsn->{have_user} and $dsn->{dsn} !~ /mysql_read_default_group=client/ ) {
      my $answer = prompt("Do you want to specify a username for $connection?", undef, 'n');
      $dsn->{have_user} = $answer && $answer =~ m/1|y/i;
   }

   # don't ask for a password if mysql_read_default_group=client is in the DSN
   if ( !defined $dsn->{have_pass} and $dsn->{dsn} !~ /mysql_read_default_group=client/ ) {
      my $answer = prompt("Do you want to specify a password for $connection?", undef, 'n');
      $dsn->{have_pass} = $answer && $answer =~ m/1|y/i;
   }

   if ( !$dsn->{user} && $dsn->{have_user} ) {
      my $user = $ENV{USERNAME} || $ENV{USER} || getlogin() || getpwuid($REAL_USER_ID) || undef;
      $dsn->{user} = prompt("Enter username for $connection", undef, $user);
   }

   if ( !defined $dsn->{user} ) {
      $dsn->{user} = '';
   }

   if ( !$dsn->{pass} && !$dsn->{savepass} && $dsn->{have_pass} ) {
      $dsn->{pass} = prompt_noecho("Enter password for '$dsn->{user}' on $connection");
      print "\n";
      if ( !defined($dsn->{savepass}) ) {
         my $answer = prompt("Save password in plain text in the config file?", undef, 'y');
         $dsn->{savepass} = $answer && $answer =~ m/1|y/i;
      }
   }

   my $dbh = DBI->connect(
      $dsn->{dsn}, $dsn->{user}, $dsn->{pass},
      { RaiseError => 1, PrintError => 0, AutoCommit => 1 });
   $dbh->{InactiveDestroy} = 1 unless $destroy; # Can't be set in $db_options
   $dbh->{FetchHashKeyName} = 'NAME_lc'; # Lowercases all column names for fetchrow_hashref
   return $dbh;
}

sub get_cxn_errors {
   my @cxns = @_;
   return () unless $config{show_cxn_errors_in_tbl}->{val};
   return
      map  { [ $_ . ': ' . $dbhs{$_}->{last_err}, 'red' ] }
      grep { $dbhs{$_} && $dbhs{$_}->{err_count} && $dbhs{$_}->{mode} eq $config{mode}->{val} }
      @cxns;
}

# Setup and tear-down functions {{{2

# Takes a string and turns it into a hashref you can apply to %tbl_meta tables.  The string
# can be in the form 'foo, bar, foo/bar, foo as bar' much like a SQL SELECT statement.
sub compile_select_stmt {
   my ($str) = @_;
   my @exps = $str =~ m/\s*([^,]+(?i:\s+as\s+[^,\s]+)?)\s*(?=,|$)/g;
   my %cols;
   my @visible;
   foreach my $exp ( @exps ) {
      my ( $text, $colname );
      if ( $exp =~ m/as\s+(\w+)\s*/ ) {
         $colname = $1;
         $exp =~ s/as\s+(\w+)\s*//;
         $text    = $exp;
      }
      else {
         $text = $colname = $exp;
      }
      my ($func, $err) = compile_expr($text);
      $cols{$colname} = {
         src  => $text,
         hdr  => $colname,
         num  => 0,
         func => $func,
      };
      push @visible, $colname;
   }
   return (\%cols, \@visible);
}

# compile_filter {{{3
sub compile_filter {
   my ( $text ) = @_;
   my ( $sub, $err );
   eval "\$sub = sub { my \$set = shift; $text }";
   if ( $EVAL_ERROR ) {
      $EVAL_ERROR =~ s/at \(eval.*$//;
      $sub = sub { return $EVAL_ERROR };
      $err = $EVAL_ERROR;
   }
   return ( $sub, $err );
}

# compile_expr {{{3
sub compile_expr {
   my ( $expr ) = @_;
   # Leave built-in functions alone so they get called as Perl functions, unless
   # they are the only word in $expr, in which case treat them as hash keys.
   if ( $expr =~ m/\W/ ) {
      $expr =~ s/(?<!\{|\$)\b([A-Za-z]\w{2,})\b/is_func($1) ? $1 : "\$set->{$1}"/eg;
   }
   else {
      $expr = "\$set->{$expr}";
   }
   my ( $sub, $err );
   my $quoted = quotemeta($expr);
   eval qq{
      \$sub = sub {
         my (\$set, \$cur, \$pre) = \@_;
         my \$val = eval { $expr };
         if ( \$EVAL_ERROR && \$config{debug}->{val} ) {
            \$EVAL_ERROR =~ s/ at \\(eval.*//s;
            die "\$EVAL_ERROR in expression $quoted";
         }
         return \$val;
      }
   };
   if ( $EVAL_ERROR ) {
      if ( $config{debug}->{val} ) {
         die $EVAL_ERROR;
      }
      $EVAL_ERROR =~ s/ at \(eval.*$//;
      $sub = sub { return $EVAL_ERROR };
      $err = $EVAL_ERROR;
   }
   return ( $sub, $err );
}

# finish {{{3
# This is a subroutine because it's called from a key to quit the program.
sub finish {
   save_config();
   ReadMode('normal') unless $opts{n};
   print "\n";
   exit(0);
}

# core_dump {{{3
sub core_dump {
   my $msg = shift;
   if ($config{debugfile}->{val} && $config{debug}->{val}) {
      eval {
         open my $file, '>>', $config{debugfile}->{val};
         if ( %vars ) {
            print $file "Current variables:\n" . Dumper(\%vars);
         }
         close $file;
      };
   }
   print $msg;
}

# migrate_config {{{3
sub migrate_config {

   my ($old_filename, $new_filename) = @_;

   # don't proceed if old file doesn't exist
   if ( ! -f $old_filename ) {
      die "Error migrating '$old_filename': file doesn't exist.\n";
   }
   # don't migrate files if new file exists
   elsif ( -f $new_filename ) {
      die "Error migrating '$old_filename' to '$new_filename': new file already exists.\n";
   }
   # if migrating from one file to another in the same directory, just rename them
   if (dirname($old_filename) eq dirname($new_filename)) {
      rename($old_filename, $new_filename)
         or die "Can't rename '$old_filename' to '$new_filename': $OS_ERROR";
   }
   # otherwise, move the existing conf file to a temp file, make the necessary directory structure,
   # and move the temp conf file to its new home
   else {
      my $tmp = File::Temp->new( TEMPLATE => 'innotopXXXXX', DIR => $homepath, SUFFIX => '.conf');
      my $tmp_filename = $tmp->filename;
      my $dirname = dirname($new_filename);
      rename($old_filename, $tmp_filename)
         or die "Can't rename '$old_filename' to '$tmp_filename': $OS_ERROR";
      mkdir($dirname) or die "Can't create directory '$dirname': $OS_ERROR";
      mkdir("$dirname/plugins") or die "Can't create directory '$dirname/plugins': $OS_ERROR";
      rename($tmp_filename, $new_filename)
         or die "Can't rename '$tmp_filename' to '$new_filename': $OS_ERROR";
   }
}

# load_config {{{3
sub load_config {
    
   my ($old_filename, $answer);

   if ( $opts{u} or $opts{p} or $opts{h} or $opts{P} ) {
     my @params = $dsn_parser->get_cxn_params(\%opts); # dsn=$params[0]
     add_new_dsn($opts{h} || 'localhost', $params[0], 'test.innotop_dl', 
                 $opts{u} ? 1 : 0, $opts{u}, $opts{p} ? 1 : 0, $opts{p});
   }
   if ($opts{c}) {
      $conf_file = $opts{c};
   }  
   # innotop got upgraded and this is an old config file.
   elsif ( -f "$homepath/.innotop" or -f "$homepath/.innotop/innotop.ini" ) {
      $conf_file = $default_home_conf;
      if ( -f  "$homepath/.innotop") {
         $old_filename = "$homepath/.innotop";
      }
      elsif ( -f "$homepath/.innotop/innotop.ini" ) {
         $old_filename = "$homepath/.innotop/innotop.ini";
      }
      $answer = pause("Innotop's default config location has moved to '$conf_file'.  Move old config file '$old_filename' there now? y/n");
      if ( lc $answer eq 'y' ) {
         migrate_config($old_filename, $conf_file);
      }
      else {
         print "\nInnotop will now exit so you can fix the config file.\n";
         exit(0);
      }
   }
   elsif ( -f $default_home_conf ) {
      $conf_file = $default_home_conf;
   }
   elsif ( -f $default_central_conf and not $opts{s} ) {
      $conf_file = $default_central_conf;
   }
   else {
      # If no config file was loaded, set readonly to 0 if the user wants to 
      # write a config
      $config{readonly}->{val} = 0 if $opts{w};
      # If no connections have been defined, connect to a MySQL database 
      # on localhost using mysql_read_default_group=client
      if (!%connections) {
         add_new_dsn('localhost', 
                     'DBI:mysql:;host=localhost;mysql_read_default_group=client', 
                     'test.innotop_dl');
      }
   }

   if ( -f "$conf_file" ) {
      open my $file, "<", $conf_file or die("Can't open '$conf_file': $OS_ERROR");

      # Check config file version.  Just ignore if either innotop or the file has
      # garbage in the version number.
      if ( defined(my $line = <$file>) && $VERSION =~ m/\d/ ) {
         chomp $line;
         if ( my ($maj, $min, $rev) = $line =~ m/^version=(\d+)\.(\d+)(?:\.(\d+))?$/ ) {
            $rev ||= 0;
            my $cfg_ver          = sprintf('%03d-%03d-%03d', $maj, $min, $rev);
            ( $maj, $min, $rev ) = $VERSION =~ m/^(\d+)\.(\d+)(?:\.(\d+))?$/;
            $rev ||= 0;
            my $innotop_ver      = sprintf('%03d-%03d-%03d', $maj, $min, $rev);

            if ( $cfg_ver gt $innotop_ver ) {
               pause("The config file is for a newer version of innotop and may not be read correctly.");
            }
            else {
               my @ver_history = @config_versions;
               while ( my ($start, $end) = splice(@ver_history, 0, 2) ) {
                  # If the config file is between the endpoints and innotop is greater than
                  # the endpoint, innotop has a newer config file format than the file.
                  if ( $cfg_ver ge $start && $cfg_ver lt $end && $innotop_ver ge $end ) {
                     my $msg = "innotop's config file format has changed.  Overwrite $conf_file?  y or n";
                     if ( pause($msg) eq 'n' ) {
                        $config{readonly}->{val} = 1;
                        print "\ninnotop will not save any configuration changes you make.";
                        pause();
                        print "\n";
                     }
                     close $file;
                     return;
                  }
               }
            }
         }
      }

      while ( my $line = <$file> ) {
         chomp $line;
         next unless $line =~ m/^\[([a-z_]+)\]$/;
         if ( exists $config_file_sections{$1} ) {
            $config_file_sections{$1}->{reader}->($file);
         }
         else {
            warn "Unknown config file section '$1'";
         }
      }
      close $file or die("Can't close $conf_file: $OS_ERROR");
   }

}

# Do some post-processing on %tbl_meta: compile src properties into func etc.
sub post_process_tbl_meta {
   foreach my $table ( values %tbl_meta ) {
      foreach my $col_name ( keys %{$table->{cols}} ) {
         my $col_def = $table->{cols}->{$col_name};
         my ( $sub, $err ) = compile_expr($col_def->{src});
         $col_def->{func} = $sub;
      }
   }
}

# load_config_plugins {{{3
sub load_config_plugins {
   my ( $file ) = @_;

   # First, find a list of all plugins that exist on disk, and get information about them.
   my $dir = $config{plugin_dir}->{val};
   foreach my $p_file ( <$dir/*.pm> ) {
      my ($package, $desc);
      eval {
         open my $p_in, "<", $p_file or die $OS_ERROR;
         while ( my $line = <$p_in> ) {
            chomp $line;
            if ( $line =~ m/^package\s+(.*?);/ ) {
               $package = $1;
            }
            elsif ( $line =~ m/^# description: (.*)/ ) {
               $desc = $1;
            }
            last if $package && $desc;
         }
         close $p_in;
      };
      if ( $package ) {
         $plugins{$package} = {
            file   => $p_file,
            desc   => $desc,
            class  => $package,
            active => 0,
         };
         if ( $config{debug}->{val} && $EVAL_ERROR ) {
            die $EVAL_ERROR;
         }
      }
   }

   # Now read which ones the user has activated.  Each line simply represents an active plugin.
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;
      next unless $line && $plugins{$line};

      my $obj;
      eval {
         require $plugins{$line}->{file};
         $obj = $line->new(%pluggable_vars);
         foreach my $event ( $obj->register_for_events() ) {
            my $queue = $event_listener_for{$event};
            if ( $queue ) {
               push @$queue, $obj;
            }
         }
      };
      if ( $config{debug}->{val} && $EVAL_ERROR ) {
         die $EVAL_ERROR;
      }
      if ( $obj ) {
         $plugins{$line}->{active} = 1;
         $plugins{$line}->{object} = $obj;
      }
   }
}

# save_config_plugins {{{3
sub save_config_plugins {
   my $file = shift;
   foreach my $class ( sort keys %plugins ) {
      next unless $plugins{$class}->{active};
      print $file "$class\n";
   }
}

# load_config_active_server_groups {{{3
sub load_config_active_server_groups {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $mode, $group ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $mode && $group
         && exists $modes{$mode} && exists $server_groups{$group};
      $modes{$mode}->{server_group} = $group;
   }
}

# save_config_active_server_groups {{{3
sub save_config_active_server_groups {
   my $file = shift;
   foreach my $mode ( sort keys %modes ) {
      print $file "$mode=$modes{$mode}->{server_group}\n";
   }
}

# load_config_server_groups {{{3
sub load_config_server_groups {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $name, $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $name && $rest;
      my @vars = unique(grep { $_ && exists $connections{$_} } split(/\s+/, $rest));
      next unless @vars;
      $server_groups{$name} = \@vars;
   }
}

# save_config_server_groups {{{3
sub save_config_server_groups {
   my $file = shift;
   foreach my $set ( sort keys %server_groups ) {
      print $file "$set=", join(' ', @{$server_groups{$set}}), "\n";
   }
}

# load_config_varsets {{{3
sub load_config_varsets {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $name, $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $name && $rest;
      $var_sets{$name} = {
         text => $rest,
         user => 1,
      };
   }
}

# save_config_varsets {{{3
sub save_config_varsets {
   my $file = shift;
   foreach my $varset ( sort keys %var_sets ) {
      next unless $var_sets{$varset}->{user};
      print $file "$varset=$var_sets{$varset}->{text}\n";
   }
}

# load_config_group_by {{{3
sub load_config_group_by {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $tbl , $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $tbl && exists $tbl_meta{$tbl};
      my @parts = unique(grep { exists($tbl_meta{$tbl}->{cols}->{$_}) } split(/\s+/, $rest));
      $tbl_meta{$tbl}->{group_by} = [ @parts ];
      $tbl_meta{$tbl}->{cust}->{group_by} = 1;
   }
}

# save_config_group_by {{{3
sub save_config_group_by {
   my $file = shift;
   foreach my $tbl ( sort keys %tbl_meta ) {
      next if $tbl_meta{$tbl}->{temp};
      next unless $tbl_meta{$tbl}->{cust}->{group_by};
      my $aref = $tbl_meta{$tbl}->{group_by};
      print $file "$tbl=", join(' ', @$aref), "\n";
   }
}

# load_config_filters {{{3
sub load_config_filters {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $key, $rest ) = $line =~ m/^(.+?)=(.*)$/;
      next unless $key && $rest;

      my %parts = $rest =~ m/(\w+)='((?:(?!(?<!\\)').)*)'/g; # Properties are single-quoted
      next unless $parts{text} && $parts{tbls};

      foreach my $prop ( keys %parts ) {
         # Un-escape escaping
         $parts{$prop} =~ s/\\\\/\\/g;
         $parts{$prop} =~ s/\\'/'/g;
      }

      my ( $sub, $err ) = compile_filter($parts{text});
      my @tbls = unique(split(/\s+/, $parts{tbls}));
      @tbls = grep { exists $tbl_meta{$_} } @tbls;
      $filters{$key} = {
         func => $sub,
         text => $parts{text},
         user => 1,
         name => $key,
         note => 'User-defined filter',
         tbls => \@tbls,
      }
   }
}

# save_config_filters {{{3
sub save_config_filters {
   my $file = shift;
   foreach my $key ( sort keys %filters ) {
      next if !$filters{$key}->{user} || $filters{$key}->{quick};
      my $text = $filters{$key}->{text};
      $text =~ s/([\\'])/\\$1/g;
      my $tbls = join(" ", @{$filters{$key}->{tbls}});
      print $file "$key=text='$text' tbls='$tbls'\n";
   }
}

# load_config_visible_tables {{{3
sub load_config_visible_tables {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $mode, $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $mode && exists $modes{$mode};
      $modes{$mode}->{visible_tables} =
         [ unique(grep { $_ && exists $tbl_meta{$_} } split(/\s+/, $rest)) ];
      $modes{$mode}->{cust}->{visible_tables} = 1;
   }
}

# save_config_visible_tables {{{3
sub save_config_visible_tables {
   my $file = shift;
   foreach my $mode ( sort keys %modes ) {
      next unless $modes{$mode}->{cust}->{visible_tables};
      my $tables = $modes{$mode}->{visible_tables};
      print $file "$mode=", join(' ', @$tables), "\n";
   }
}

# load_config_sort_cols {{{3
sub load_config_sort_cols {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $key , $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $key && exists $tbl_meta{$key};
      $tbl_meta{$key}->{sort_cols} = $rest;
      $tbl_meta{$key}->{cust}->{sort_cols} = 1;
      $tbl_meta{$key}->{sort_func} = make_sort_func($tbl_meta{$key});
   }
}

# save_config_sort_cols {{{3
sub save_config_sort_cols {
   my $file = shift;
   foreach my $tbl ( sort keys %tbl_meta ) {
      next unless $tbl_meta{$tbl}->{cust}->{sort_cols};
      my $col = $tbl_meta{$tbl}->{sort_cols};
      print $file "$tbl=$col\n";
   }
}

# load_config_active_filters {{{3
sub load_config_active_filters {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $tbl , $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $tbl && exists $tbl_meta{$tbl};
      my @parts = unique(grep { exists($filters{$_}) } split(/\s+/, $rest));
      @parts = grep { grep { $tbl eq $_ } @{$filters{$_}->{tbls}} } @parts;
      $tbl_meta{$tbl}->{filters} = [ @parts ];
      $tbl_meta{$tbl}->{cust}->{filters} = 1;
   }
}

# save_config_active_filters {{{3
sub save_config_active_filters {
   my $file = shift;
   foreach my $tbl ( sort keys %tbl_meta ) {
      next if $tbl_meta{$tbl}->{temp};
      next unless $tbl_meta{$tbl}->{cust}->{filters};
      my $aref = $tbl_meta{$tbl}->{filters};
      print $file "$tbl=", join(' ', @$aref), "\n";
   }
}

# load_config_active_columns {{{3
sub load_config_active_columns {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $key , $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $key && exists $tbl_meta{$key};
      my @parts = grep { exists($tbl_meta{$key}->{cols}->{$_}) } unique split(/ /, $rest);
      $tbl_meta{$key}->{visible} = [ @parts ];
      $tbl_meta{$key}->{cust}->{visible} = 1;
   }
}

# save_config_active_columns {{{3
sub save_config_active_columns {
   my $file = shift;
   foreach my $tbl ( sort keys %tbl_meta ) {
      next unless $tbl_meta{$tbl}->{cust}->{visible};
      my $aref = $tbl_meta{$tbl}->{visible};
      print $file "$tbl=", join(' ', @$aref), "\n";
   }
}

# save_config_tbl_meta {{{3
sub save_config_tbl_meta {
   my $file = shift;
   foreach my $tbl ( sort keys %tbl_meta ) {
      foreach my $col ( keys %{$tbl_meta{$tbl}->{cols}} ) {
         my $meta = $tbl_meta{$tbl}->{cols}->{$col};
         next unless $meta->{user};
         print $file "$col=", join(
            " ",
            map {
               # Some properties (trans) are arrays, others scalars
               my $val = ref($meta->{$_}) ? join(',', @{$meta->{$_}}) : $meta->{$_};
               $val =~ s/([\\'])/\\$1/g;  # Escape backslashes and single quotes
               "$_='$val'";               # Enclose in single quotes
            }
            grep { $_ ne 'func' }
            keys %$meta
         ), "\n";
      }
   }
}

# save_config_config {{{3
sub save_config_config {
   my $file = shift;
   foreach my $key ( sort keys %config ) {
      eval {
      if ( $key ne 'password' || $config{savepass}->{val} ) {
         print $file "# $config{$key}->{note}\n"
            or die "Cannot print to file: $OS_ERROR";
         my $val = $config{$key}->{val};
         $val = '' unless defined($val);
         if ( ref( $val ) eq 'ARRAY' ) {
            print $file "$key="
               . join( " ", @$val ) . "\n"
               or die "Cannot print to file: $OS_ERROR";
         }
         elsif ( ref( $val ) eq 'HASH' ) {
            print $file "$key="
               . join( " ",
                  map { "$_:$val->{$_}" } keys %$val
               ) . "\n";
         }
         else {
            print $file "$key=$val\n";
         }
      }
      };
      if ( $EVAL_ERROR ) { print "$EVAL_ERROR in $key"; };
   }

}

# load_config_config {{{3
sub load_config_config {
   my ( $file ) = @_;

   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $name, $val ) = $line =~ m/^(.+?)=(.*)$/;
      next unless defined $name && defined $val;

      # Validate the incoming values...
      if ( $name && exists( $config{$name} ) ) {
         if ( !$config{$name}->{pat} || $val =~ m/$config{$name}->{pat}/ ) {
            $config{$name}->{val} = $val;
            $config{$name}->{read} = 1;
         }
      }
   }
}

# load_config_tbl_meta {{{3
sub load_config_tbl_meta {
   my ( $file ) = @_;

   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      # Each tbl_meta section has all the properties defined in %col_props.
      my ( $col , $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $col;
      my %parts = $rest =~ m/(\w+)='((?:(?!(?<!\\)').)*)'/g; # Properties are single-quoted

      # Each section read from the config file has one extra property: which table it
      # goes in.
      my $tbl  = $parts{tbl}     or die "There's no table for tbl_meta $col";
      my $meta = $tbl_meta{$tbl} or die "There's no table in tbl_meta named $tbl";

      # The section is user-defined by definition (if that makes sense).
      $parts{user} = 1;

      # The column may already exist in the table, in which case this is just a
      # customization.
      $meta->{cols}->{$col} ||= {};

      foreach my $prop ( keys %col_props ) {
         if ( !defined($parts{$prop}) ) {
            die "Undefined property $prop for column $col in table $tbl";
         }

         # Un-escape escaping
         $parts{$prop} =~ s/\\\\/\\/g;
         $parts{$prop} =~ s/\\'/'/g;

         if ( ref $col_props{$prop} ) {
            if ( $prop eq 'trans' ) {
               $meta->{cols}->{$col}->{trans}
                  = [ unique(grep { exists $trans_funcs{$_} } split(',', $parts{$prop})) ];
            }
            else {
               $meta->{cols}->{$col}->{$prop} = [ split(',', $parts{$prop}) ];
            }
         }
         else {
            $meta->{cols}->{$col}->{$prop} = $parts{$prop};
         }
      }

   }
}

# save_config {{{3
sub save_config {
   print "\n";
   return if $config{readonly}->{val};
   # return if no config file was loaded and -w wasn't specified
   if (not $conf_file) {
      if (not $opts{w}) {
         return;
      }
      else {
         # if no config was loaded but -w was specified,
         # write to $default_home_conf
         $conf_file = $default_home_conf;
      }
   }
   elsif ($conf_file and $opts{w}) {
     print "Loaded config file on start-up, so ignoring -w (see --help)\n"
   }
   
   my $dirname  = dirname($conf_file);

   # if directories don't exist, create them.  This could cause errors
   # or warnings if a central config doesn't have readonly=1, but being
   # flexible requires giving the user enough rope to hang themselves with.
   if ( ! -d $dirname ) {
      mkdir $dirname
         or die "Can't create directory '$dirname': $OS_ERROR";
   }
   if ( ! -d "$dirname/plugins" ) {
      mkdir "$dirname/plugins"
         or warn "Can't create directory '$dirname/plugins': $OS_ERROR\n";
   }

   # Save to a temp file first, so a crash doesn't destroy the main config file
   my $tmpfile = File::Temp->new( TEMPLATE => 'innotopXXXXX', DIR => $dirname, SUFFIX => '.conf.tmp');
   open my $file, "+>", $tmpfile
      or die("Can't write to $tmpfile: $OS_ERROR");
   print $file "version=$VERSION\n";

   foreach my $section ( @ordered_config_file_sections ) {
      die "No such config file section $section" unless $config_file_sections{$section};
      print $file "\n[$section]\n\n";
      $config_file_sections{$section}->{writer}->($file);
      print $file "\n[/$section]\n";
   }

   # Now clobber the main config file with the temp.
   close $file or die("Can't close $tmpfile: $OS_ERROR");
   rename($tmpfile, $conf_file) or die("Can't rename $tmpfile to $conf_file: $OS_ERROR");
}

# load_config_connections {{{3
sub load_config_connections {
   return if $opts{u} or $opts{p} or $opts{h} or $opts{P}; # don't load connections if DSN or user/pass options used
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $key , $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $key;
      my %parts = $rest =~ m/(\S+?)=(\S*)/g;
      my %conn  = map { $_ => $parts{$_} || '' } @conn_parts;
      $connections{$key} = \%conn;
   }
}

# save_config_connections {{{3
sub save_config_connections {
   my $file = shift;
   foreach my $conn ( sort keys %connections ) {
      my $href = $connections{$conn};
      my @keys = $href->{savepass} ? @conn_parts : grep { $_ ne 'pass' } @conn_parts;
      print $file "$conn=", join(' ', map { "$_=$href->{$_}" } grep { defined $href->{$_} } @keys), "\n";
   }
}

sub load_config_colors {
   my ( $file ) = @_;
   my %rule_set_for;

   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $tbl, $rule ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $tbl && $rule;
      next unless exists $tbl_meta{$tbl};
      my %parts = $rule =~ m/(\w+)='((?:(?!(?<!\\)').)*)'/g; # Properties are single-quoted
      next unless $parts{col} && exists $tbl_meta{$tbl}->{cols}->{$parts{col}};
      next unless $parts{op}  && exists $comp_ops{$parts{op}};
      next unless defined $parts{arg};
      next unless defined $parts{color};
      my @colors = unique(grep { exists $ansicolors{$_} } split(/\W+/, $parts{color}));
      next unless @colors;

      # Finally!  Enough validation...
      $rule_set_for{$tbl} ||= [];
      push @{$rule_set_for{$tbl}}, \%parts;
   }

   foreach my $tbl ( keys %rule_set_for ) {
      $tbl_meta{$tbl}->{colors} = $rule_set_for{$tbl};
      $tbl_meta{$tbl}->{color_func} = make_color_func($tbl_meta{$tbl});
      $tbl_meta{$tbl}->{cust}->{colors} = 1;
   }
}

# save_config_colors {{{3
sub save_config_colors {
   my $file = shift;
   foreach my $tbl ( sort keys %tbl_meta ) {
      my $meta = $tbl_meta{$tbl};
      next unless $meta->{cust}->{colors};
      foreach my $rule ( @{$meta->{colors}} ) {
         print $file "$tbl=", join(
            ' ',
            map {
               my $val = $rule->{$_};
               $val =~ s/([\\'])/\\$1/g;  # Escape backslashes and single quotes
               "$_='$val'";               # Enclose in single quotes
            }
            qw(col op arg color)
         ), "\n";
      }
   }
}

# load_config_active_connections {{{3
sub load_config_active_connections {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $key , $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $key && exists $modes{$key};
      my @parts = grep { exists $connections{$_} } split(/ /, $rest);
      $modes{$key}->{connections} = [ @parts ] if exists $modes{$key};
   }
}

# save_config_active_connections {{{3
sub save_config_active_connections {
   my $file = shift;
   foreach my $mode ( sort keys %modes ) {
      my @connections = get_connections($mode);
      print $file "$mode=", join(' ', @connections), "\n";
   }
}

# load_config_stmt_sleep_times {{{3
sub load_config_stmt_sleep_times {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $key , $val ) = split('=', $line);
      next unless $key && defined $val && $val =~ m/$num_regex/;
      $stmt_sleep_time_for{$key} = $val;
   }
}

# save_config_stmt_sleep_times {{{3
sub save_config_stmt_sleep_times {
   my $file = shift;
   foreach my $key ( sort keys %stmt_sleep_time_for ) {
      print $file "$key=$stmt_sleep_time_for{$key}\n";
   }
}

# load_config_mvs {{{3
sub load_config_mvs {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $key , $val ) = split('=', $line);
      next unless $key && defined $val && $val =~ m/$num_regex/;
      $mvs{$key} = $val;
   }
}

# save_config_mvs {{{3
sub save_config_mvs {
   my $file = shift;
   foreach my $key ( sort keys %mvs ) {
      print $file "$key=$mvs{$key}\n";
   }
}

# edit_configuration {{{3
sub edit_configuration {
   my $key = '';
   while ( $key ne 'q' ) {
      $clear_screen_sub->();
      my @display_lines = '';

      if ( $key && $cfg_editor_action{$key} ) {
         $cfg_editor_action{$key}->{func}->();
      }

      # Show help
      push @display_lines, create_caption('What configuration do you want to edit?',
      create_table2(
         [ sort keys %cfg_editor_action ],
         { map { $_ => $_ } keys %cfg_editor_action },
         { map { $_ => $cfg_editor_action{$_}->{note} } keys %cfg_editor_action },
         { sep => '  ' }));

      draw_screen(\@display_lines);
      $key = pause('');
   }
}

# edit_configuration_variables {{{3
sub edit_configuration_variables {
   $clear_screen_sub->();
   my $mode = $config{mode}->{val};

   my %config_choices
      = map  { $_ => $config{$_}->{note} || '' }
        # Only config values that are marked as applying to this mode.
        grep {
           my $key = $_;
           $config{$key}->{conf} &&
              ( $config{$key}->{conf} eq 'ALL'
              || grep { $mode eq $_ } @{$config{$key}->{conf}} )
        } keys %config;

   my $key = prompt_list(
      "Enter the name of the variable you wish to configure",
      '',
      sub{ return keys %config_choices },
      \%config_choices);

   if ( exists($config_choices{$key}) ) {
      get_config_interactive($key);
   }
}

# edit_color_rules {{{3
sub edit_color_rules {
   my ( $tbl ) = @_;
   $clear_screen_sub->();
   $tbl ||= choose_visible_table();
   if ( $tbl && exists($tbl_meta{$tbl}) ) {
      my $meta = $tbl_meta{$tbl};
      my @cols = ('', qw(col op arg color));
      my $info = { map { $_ => { hdr => $_, just => '-', } }  @cols };
      $info->{label}->{maxw} = 30;
      my $key;
      my $selected_rule;

      # This loop builds a tabular view of the rules.
      do {

         # Show help
         if ( $key && $key eq '?' ) {
            my @display_lines = '';
            push @display_lines, create_caption('Editor key mappings',
            create_table2(
               [ sort keys %color_editor_action ],
               { map { $_ => $_ } keys %color_editor_action },
               { map { $_ => $color_editor_action{$_}->{note} } keys %color_editor_action },
               { sep => '  ' }));
            draw_screen(\@display_lines);
            pause();
            $key = '';
         }
         else {

            # Do the action specified
            $selected_rule ||= 0;
            if ( $key && $color_editor_action{$key} ) {
               $selected_rule = $color_editor_action{$key}->{func}->($tbl, $selected_rule);
               $selected_rule ||= 0;
            }

            # Build the table of rules.  If the terminal has color, the selected rule
            # will be highlighted; otherwise a > at the left will indicate.
            my $data = $meta->{colors} || [];
            foreach my $i ( 0..@$data - 1  ) {
               $data->[$i]->{''} = $i == $selected_rule ? '>' : '';
            }
            my @display_lines = create_table(\@cols, $info, $data);

            # Highlight selected entry
            for my $i ( 0 .. $#display_lines ) {
               if ( $display_lines[$i] =~ m/^>/ ) {
                  $display_lines[$i] = [ $display_lines[$i], 'reverse' ];
               }
            }

            # Draw the screen and wait for a command.
            unshift @display_lines, '',
               "Editing color rules for $meta->{capt}.  Press ? for help, q to "
               . "quit.", '';
            draw_screen(\@display_lines);
            print "\n\n", word_wrap('Rules are applied in order from top to '
               . 'bottom.  The first matching rule wins and prevents the '
               . 'rest of the rules from being applied.');
            $key = pause('');
         }
      } while ( $key ne 'q' );
      $meta->{color_func} = make_color_func($meta);
   }
}

# add_quick_filter {{{3
sub add_quick_filter {
   my $tbl = choose_visible_table();
   if ( $tbl && exists($tbl_meta{$tbl}) ) {
      print "\n";
      my $response = prompt_list(
         "Enter column name and filter text",
         '',
         sub { return keys %{$tbl_meta{$tbl}->{cols}} },
         ()
      );
      my ( $col, $text ) = split(/\s+/, $response, 2);

      # You can't filter on a nonexistent column.  But if you filter on a pivoted
      # table, the columns are different, so on a pivoted table, allow filtering
      # on the 'name' column.
      # NOTE: if a table is pivoted and un-pivoted, this will likely cause crashes.
      # Currently not an issue since there's no way to toggle pivot/nopivot.
      return unless $col && $text &&
         (exists($tbl_meta{$tbl}->{cols}->{$col})
            || ($tbl_meta{$tbl}->{pivot} && $col eq 'name'));

      my ( $sub, $err ) = compile_filter( "defined \$set->{$col} && \$set->{$col} =~ m/$text/" );
      return if !$sub || $err;
      my $name = "quick_$tbl.$col";
      $filters{$name} = {
         func  => $sub,
         text  => $text,
         user  => 1,
         quick => 1,
         name  => $name,
         note  => 'Quick-filter',
         tbls  => [$tbl],
      };
      push @{$tbl_meta{$tbl}->{filters}}, $name;
   }
}

# clear_quick_filters {{{3
sub clear_quick_filters {
   my $tbl = choose_visible_table(
      # Only tables that have quick-filters
      sub {
         my ( $tbl ) = @_;
         return scalar grep { $filters{$_}->{quick} } @{ $tbl_meta{$tbl}->{filters} };
      }
   );
   if ( $tbl && exists($tbl_meta{$tbl}) ) {
      my @current = @{$tbl_meta{$tbl}->{filters}};
      @current = grep { !$filters{$_}->{quick} } @current;
      $tbl_meta{$tbl}->{filters} = \@current;
   }
}

sub edit_plugins {
   $clear_screen_sub->();

   my @cols = ('', qw(class desc active));
   my $info = { map { $_ => { hdr => $_, just => '-', } }  @cols };
   my @rows = map { $plugins{$_} } sort keys %plugins;
   my $key;
   my $selected;

   # This loop builds a tabular view of the plugins.
   do {

      # Show help
      if ( $key && $key eq '?' ) {
         my @display_lines = '';
         push @display_lines, create_caption('Editor key mappings',
         create_table2(
            [ sort keys %plugin_editor_action ],
            { map { $_ => $_ } keys %plugin_editor_action },
            { map { $_ => $plugin_editor_action{$_}->{note} } keys %plugin_editor_action },
            { sep => '  ' }));
         draw_screen(\@display_lines);
         pause();
         $key = '';
      }

      # Do the action specified
      else {
         $selected ||= 0;
         if ( $key && $plugin_editor_action{$key} ) {
            $selected = $plugin_editor_action{$key}->{func}->(\@rows, $selected);
            $selected ||= 0;
         }

         # Build the table of plugins.
         foreach my $row ( 0.. $#rows ) {
            $rows[$row]->{''} = $row eq $selected ? '>' : ' ';
         }
         my @display_lines = create_table(\@cols, $info, \@rows);

         # Highlight selected entry
         for my $i ( 0 .. $#display_lines ) {
            if ( $display_lines[$i] =~ m/^>/ ) {
               $display_lines[$i] = [ $display_lines[$i], 'reverse' ];
            }
         }

         # Draw the screen and wait for a command.
         unshift @display_lines, '',
            "Plugin Management.  Press ? for help, q to quit.", '';
         draw_screen(\@display_lines);
         $key = pause('');
      }
   } while ( $key ne 'q' );
}

# edit_table {{{3
sub edit_table {
   $clear_screen_sub->();
   my ( $tbl ) = @_;
   $tbl ||= choose_visible_table();
   if ( $tbl && exists($tbl_meta{$tbl}) ) {
      my $meta = $tbl_meta{$tbl};
      my @cols = ('', qw(name hdr label src));
      my $info = { map { $_ => { hdr => $_, just => '-', } }  @cols };
      $info->{label}->{maxw} = 30;
      my $key;
      my $selected_column;

      # This loop builds a tabular view of the tbl_meta's structure, showing each column
      # in the entry as a row.
      do {

         # Show help
         if ( $key && $key eq '?' ) {
            my @display_lines = '';
            push @display_lines, create_caption('Editor key mappings',
            create_table2(
               [ sort keys %tbl_editor_action ],
               { map { $_ => $_ } keys %tbl_editor_action },
               { map { $_ => $tbl_editor_action{$_}->{note} } keys %tbl_editor_action },
               { sep => '  ' }));
            draw_screen(\@display_lines);
            pause();
            $key = '';
         }
         else {

            # Do the action specified
            $selected_column ||= $meta->{visible}->[0];
            if ( $key && $tbl_editor_action{$key} ) {
               $selected_column = $tbl_editor_action{$key}->{func}->($tbl, $selected_column);
               $selected_column ||= $meta->{visible}->[0];
            }

            # Build the pivoted view of the table's meta-data.  If the terminal has color,
            # The selected row will be highlighted; otherwise a > at the left will indicate.
            my $data = [];
            foreach my $row ( @{$meta->{visible}} ) {
               my %hash;
               @hash{ @cols } = @{$meta->{cols}->{$row}}{@cols};
               $hash{src}  = '' if ref $hash{src};
               $hash{name} = $row;
               $hash{''}   = $row eq $selected_column ? '>' : ' ';
               push @$data, \%hash;
            }
            my @display_lines = create_table(\@cols, $info, $data);

            # Highlight selected entry
            for my $i ( 0 .. $#display_lines ) {
               if ( $display_lines[$i] =~ m/^>/ ) {
                  $display_lines[$i] = [ $display_lines[$i], 'reverse' ];
               }
            }

            # Draw the screen and wait for a command.
            unshift @display_lines, '',
               "Editing table definition for $meta->{capt}.  Press ? for help, q to quit.", '';
            draw_screen(\@display_lines, { clear => 1 });
            $key = pause('');
         }
      } while ( $key ne 'q' );
   }
}

# choose_mode_tables {{{3
# Choose which table(s), and in what order, to display in a given mode.
sub choose_mode_tables {
   my $mode = $config{mode}->{val};
   my @tbls = @{$modes{$mode}->{visible_tables}};
   my $new  = prompt_list(
      "Choose tables to display",
      join(' ', @tbls),
      sub { return @{$modes{$mode}->{tables}} },
      { map { $_ => $tbl_meta{$_}->{capt} } @{$modes{$mode}->{tables}} }
   );
   $modes{$mode}->{visible_tables} =
      [ unique(grep { $_ && exists $tbl_meta{$_} } split(/\s+/, $new)) ];
   $modes{$mode}->{cust}->{visible_tables} = 1;
}

# choose_visible_table {{{3
sub choose_visible_table {
   my ( $grep_cond ) = @_;
   my $mode = $config{mode}->{val};
   my @tbls
      = grep { $grep_cond ? $grep_cond->($_) : 1 }
        @{$modes{$mode}->{visible_tables}};
   my $tbl = $tbls[0];
   if ( @tbls > 1 ) {
      $tbl = prompt_list(
         "Choose a table",
         '',
         sub { return @tbls },
         { map { $_ => $tbl_meta{$_}->{capt} } @tbls }
      );
   }
   return $tbl;
}

sub toggle_aggregate {
   my ( $tbl ) = @_;
   $tbl ||= choose_visible_table();
   return unless $tbl && exists $tbl_meta{$tbl};
   my $meta = $tbl_meta{$tbl};
   $meta->{aggregate} ^= 1;
}

sub choose_filters {
   my ( $tbl ) = @_;
   $tbl ||= choose_visible_table();
   return unless $tbl && exists $tbl_meta{$tbl};
   my $meta = $tbl_meta{$tbl};
   $clear_screen_sub->();

   print "Choose filters for $meta->{capt}:\n";

   my $ini = join(' ', @{$meta->{filters}});
   my $val = prompt_list(
      'Choose filters',
      $ini,
      sub { return keys %filters },
      {
         map  { $_ => $filters{$_}->{note} }
         grep { grep { $tbl eq $_ } @{$filters{$_}->{tbls}} }
         keys %filters
      }
   );

   my @choices = unique(split(/\s+/, $val));
   foreach my $new ( grep { !exists($filters{$_}) } @choices ) {
      my $answer = prompt("There is no filter called '$new'.  Create it?", undef, 'y');
      if ( $answer eq 'y' ) {
         create_new_filter($new, $tbl);
      }
   }
   @choices = grep { exists $filters{$_} } @choices;
   @choices = grep { grep { $tbl eq $_ } @{$filters{$_}->{tbls}} } @choices;
   $meta->{filters} = [ @choices ];
   $meta->{cust}->{filters} = 1;
}

sub choose_group_cols {
   my ( $tbl ) = @_;
   $tbl ||= choose_visible_table();
   return unless $tbl && exists $tbl_meta{$tbl};
   $clear_screen_sub->();
   my $meta = $tbl_meta{$tbl};
   my $curr = join(', ', @{$meta->{group_by}});
   my $val = prompt_list(
      'Group-by columns',
      $curr,
      sub { return keys %{$meta->{cols}} },
      { map { $_ => $meta->{cols}->{$_}->{label} } keys %{$meta->{cols}} });
   if ( $curr ne $val ) {
      $meta->{group_by} = [ grep { exists $meta->{cols}->{$_} } $val =~ m/(\w+)/g ];
      $meta->{cust}->{group_by} = 1;
   }
}

sub choose_sort_cols {
   my ( $tbl ) = @_;
   $tbl ||= choose_visible_table();
   return unless $tbl && exists $tbl_meta{$tbl};
   $clear_screen_sub->();
   my $meta = $tbl_meta{$tbl};

   my ( $cols, $hints );
   if ( $meta->{pivot} ) {
      $cols  = sub { qw(name set_0) };
      $hints = { name => 'name', set_0 => 'set_0' };
   }
   else {
      $cols  = sub { return keys %{$meta->{cols}} };
      $hints = { map { $_ => $meta->{cols}->{$_}->{label} } keys %{$meta->{cols}} };
   }

   my $val = prompt_list(
      'Sort columns (reverse sort with -col)',
      $meta->{sort_cols},
      $cols,
      $hints );
   if ( $meta->{sort_cols} ne $val ) {
      $meta->{sort_cols} = $val;
      $meta->{cust}->{sort_cols} = 1;
      $tbl_meta{$tbl}->{sort_func} = make_sort_func($tbl_meta{$tbl});
   }
}

# create_new_filter {{{3
sub create_new_filter {
   my ( $filter, $tbl ) = @_;
   $clear_screen_sub->();

   if ( !$filter || $filter =~ m/\W/ ) {
      print word_wrap("Choose a name for the filter.  This name is not displayed, and is only used "
            . "for internal reference.  It can only contain lowercase letters, numbers, and underscores.");
      print "\n\n";
      do {
         $filter = prompt("Enter filter name");
      } while ( !$filter || $filter =~ m/\W/ );
   }

   my $completion = sub { keys %{$tbl_meta{$tbl}->{cols}} };
   my ( $err, $sub, $body );
   do {
      $clear_screen_sub->();
      print word_wrap("A filter is a Perl subroutine that accepts a hashref of columns "
         . "called \$set, and returns a true value if the filter accepts the row.  Example:\n"
         . "   \$set->{active_secs} > 5\n"
         . "will only allow rows if their active_secs column is greater than 5.");
      print "\n\n";
      if ( $err ) {
         print "There's an error in your filter expression: $err\n\n";
      }
      $body = prompt("Enter subroutine body", undef, undef, $completion);
      ( $sub, $err ) = compile_filter($body);
   } while ( $err );

   $filters{$filter} = {
      func => $sub,
      text => $body,
      user => 1,
      name => $filter,
      note => 'User-defined filter',
      tbls => [$tbl],
   };
}

# get_config_interactive {{{3
sub get_config_interactive {
   my $key = shift;
   $clear_screen_sub->();

   # Print help first.
   print "Enter a new value for '$key' ($config{$key}->{note}).\n";

   my $current = ref($config{$key}->{val}) ? join(" ", @{$config{$key}->{val}}) : $config{$key}->{val};

   my $new_value = prompt('Enter a value', $config{$key}->{pat}, $current);
   $config{$key}->{val} = $new_value;
}

sub edit_current_var_set {
   my $mode = $config{mode}->{val};
   my $name = $config{"${mode}_set"}->{val};
   my $variables = $var_sets{$name}->{text};

   my $new = $variables;
   do {
      $clear_screen_sub->();
      $new = prompt("Enter variables for $name", undef, $variables);
   } until ( $new );

   if ( $new ne $variables ) {
      @{$var_sets{$name}}{qw(text user)} = ( $new, 1);
   }
}


sub choose_var_set {
   my ( $key ) = @_;
   $clear_screen_sub->();

   my $new_value = prompt_list(
      'Choose a set of values to display, or enter the name of a new one',
      $config{$key}->{val},
      sub { return keys %var_sets },
      { map { $_ => $var_sets{$_}->{text} } keys %var_sets });

   if ( !exists $var_sets{$new_value} ) {
      add_new_var_set($new_value);
   }

   $config{$key}->{val} = $new_value if exists $var_sets{$new_value};
}

sub switch_var_set {
   my ( $cfg_var, $dir ) = @_;
   my @var_sets = sort keys %var_sets;
   my $cur      = $config{$cfg_var}->{val};
   my $pos      = grep { $_ lt $cur } @var_sets;
   my $newpos   = ($pos + $dir) % @var_sets;
   $config{$cfg_var}->{val} = $var_sets[$newpos];
   $clear_screen_sub->();
}

# Online configuration and prompting functions {{{2

# edit_stmt_sleep_times {{{3
sub edit_stmt_sleep_times {
   $clear_screen_sub->();
   my $stmt = prompt_list('Specify a statement', '', sub { return sort keys %stmt_maker_for });
   return unless $stmt && exists $stmt_maker_for{$stmt};
   $clear_screen_sub->();
   my $curr_val = $stmt_sleep_time_for{$stmt} || 0;
   my $new_val  = prompt('Specify a sleep delay after calling this SQL', $num_regex, $curr_val);
   if ( $new_val ) {
      $stmt_sleep_time_for{$stmt} = $new_val;
   }
   else {
      delete $stmt_sleep_time_for{$stmt};
   }
}

# edit_server_groups {{{3
# Choose which server connections are in a server group.  First choose a group,
# then choose which connections are in it.
sub edit_server_groups {
   $clear_screen_sub->();
   my $mode  = $config{mode}->{val};
   my $group = $modes{$mode}->{server_group};
   my %curr  = %server_groups;
   my $new   = choose_or_create_server_group($group, 'to edit');
   $clear_screen_sub->();
   if ( exists $curr{$new} ) {
      # Don't do this step if the user just created a new server group,
      # because part of that process was to choose connections.
      my $cxns  = join(' ', @{$server_groups{$new}});
      my @conns = choose_or_create_connection($cxns, 'for this group');
      $server_groups{$new} = \@conns;
   }
}

# choose_server_groups {{{3
sub choose_server_groups {
   $clear_screen_sub->();
   my $mode  = $config{mode}->{val};
   my $group = $modes{$mode}->{server_group};
   my $new   = choose_or_create_server_group($group, 'for this mode');
   $modes{$mode}->{server_group} = $new if exists $server_groups{$new};
}

sub choose_or_create_server_group {
   my ( $group, $prompt ) = @_;
   my $new   = '';

   my @available = sort keys %server_groups;

   if ( @available ) {
      print "You can enter the name of a new group to create it.\n";

      $new = prompt_list(
         "Choose a server group $prompt",
         $group,
         sub { return @available },
         { map { $_ => join(' ', @{$server_groups{$_}}) } @available });

      $new =~ s/\s.*//;

      if ( !exists $server_groups{$new} ) {
         my $answer = prompt("There is no server group called '$new'.  Create it?", undef, "y");
         if ( $answer eq 'y' ) {
            add_new_server_group($new);
         }
      }
   }
   else {
      $new = add_new_server_group();
   }
   return $new;
}

sub choose_or_create_connection {
   my ( $cxns, $prompt ) = @_;
   print "You can enter the name of a new connection to create it.\n";

   my @available = sort keys %connections;
   my $new_cxns = prompt_list(
      "Choose connections $prompt",
      $cxns,
      sub { return @available },
      { map { $_ => $connections{$_}->{dsn} } @available });

   my @new = unique(grep { !exists $connections{$_} } split(/\s+/, $new_cxns));
   foreach my $new ( @new ) {
      my $answer = prompt("There is no connection called '$new'.  Create it?", undef, "y");
      if ( $answer eq 'y' ) {
         add_new_dsn($new);
      }
   }

   return unique(grep { exists $connections{$_} } split(/\s+/, $new_cxns));
}

# choose_servers {{{3
sub choose_servers {
   $clear_screen_sub->();
   my $mode = $config{mode}->{val};
   my $cxns = join(' ', get_connections());
   my @chosen = choose_or_create_connection($cxns, 'for this mode');
   $modes{$mode}->{connections} = \@chosen;
   $modes{$mode}->{server_group} = ''; # Clear this because it overrides {connections}
}

# display_license {{{3
sub display_license {
   $clear_screen_sub->();

   print $innotop_license;

   pause();
}

# Data-retrieval functions {{{2
# get_status_info {{{3
# Get SHOW STATUS and SHOW VARIABLES together.
sub get_status_info {
   my @cxns = @_;
   if ( !$info_gotten{status}++ ) {
      foreach my $cxn ( @cxns ) {
         $vars{$cxn}->{$clock} ||= {};
         my $vars = $vars{$cxn}->{$clock};

         my $sth = do_stmt($cxn, 'SHOW_STATUS') or next;
         my $res = $sth->fetchall_arrayref();
         map { $vars->{$_->[0]} = $_->[1] || 0 } @$res;

         # Calculate hi-res uptime and add cxn to the hash.  This duplicates get_driver_status,
         # but it's most important to have consistency.
         $vars->{Uptime_hires} ||= get_uptime($cxn);
         $vars->{cxn} = $cxn;

         # Add SHOW VARIABLES to the hash
         $sth = do_stmt($cxn, 'SHOW_VARIABLES') or next;
         $res = $sth->fetchall_arrayref();
         map { $vars->{$_->[0]} = $_->[1] || 0 } @$res;
      }
   }
}

# Chooses a thread for explaining, killing, etc...
# First arg is a func that can be called in grep.
sub choose_thread {
   my ( $grep_cond, $prompt ) = @_;

   # Narrow the list to queries that can be explained.
   my %thread_for = map {
      # Eliminate innotop's own threads.
      $_ => $dbhs{$_}->{dbh} ? $dbhs{$_}->{dbh}->{mysql_thread_id} : 0
   } keys %connections;

   my @candidates = grep {
      $_->{id} != $thread_for{$_->{cxn}} && $grep_cond->($_)
   } @current_queries;
   return unless @candidates;

   # Find out which server.
   my @cxns = unique map { $_->{cxn} } @candidates;
   my ( $cxn ) = select_cxn('On which server', @cxns);
   return unless $cxn && exists($connections{$cxn});

   # Re-filter the list of candidates to only those on this server
   @candidates = grep { $_->{cxn} eq $cxn } @candidates;

   # Find out which thread to do.
   my $info;
   if ( @candidates > 1 ) {

      # Sort longest-active first, then longest-idle.
      my $sort_func = sub {
         my ( $a, $b ) = @_;
         return  $a->{query} && !$b->{query} ? 1
               : $b->{query} && !$a->{query} ? -1
               : ($a->{time} || 0) <=> ($b->{time} || 0);
      };
      my @threads = map { $_->{id} } reverse sort { $sort_func->($a, $b) } @candidates;

      print "\n";
      my $thread = prompt_list($prompt,
         $threads[0],
         sub { return @threads });
      return unless $thread && $thread =~ m/$int_regex/;

      # Find the info hash of that query on that server.
      ( $info ) = grep { $thread == $_->{id} } @candidates;
   }
   else {
      $info = $candidates[0];
   }
   return $info;
}

# analyze_query {{{3
# Allows the user to show fulltext, explain, show optimized...
sub analyze_query {
   my ( $action ) = @_;

   my $info = choose_thread(
      sub { $_[0]->{query} },
      'Select a thread to analyze',
   );
   return unless $info;

   my %actions = (
      e => \&display_explain,
      f => \&show_full_query,
      o => \&show_optimized_query,
   );
   do {
      $actions{$action}->($info);
      print "\n";
      $action = pause('Press e to explain, f for full query, o for optimized query');
   } while ( exists($actions{$action}) );
}

# inc {{{3
# Returns the difference between two sets of variables/status/innodb stuff.
sub inc {
   my ( $offset, $cxn ) = @_;
   my $vars = $vars{$cxn};
   if ( $offset < 0 ) {
      return $vars->{$clock};
   }
   elsif ( exists $vars{$clock - $offset} && !exists $vars->{$clock - $offset - 1} ) {
      return $vars->{$clock - $offset};
   }
   my $cur = $vars->{$clock - $offset};
   my $pre = $vars->{$clock - $offset - 1};
   return {
      # Numeric variables get subtracted, non-numeric get passed straight through.
      map  {
         $_ =>
            ( (defined $cur->{$_} && $cur->{$_} =~ m/$num_regex/)
            ?  $cur->{$_} - ($pre->{$_} || 0)
            :  $cur->{$_} )
      } keys %{$cur}
   };
}

# extract_values {{{3
# Arguments are a set of values (which may be incremental, derived from
# current and previous), current, and previous values.
# TODO: there are a few places that don't remember prev set so can't pass it.
sub extract_values {
   my ( $set, $cur, $pre, $tbl ) = @_;

   # Hook in event listeners
   foreach my $listener ( @{$event_listener_for{extract_values}} ) {
      $listener->extract_values($set, $cur, $pre, $tbl);
   }

   my $result = {};
   my $meta   = $tbl_meta{$tbl};
   my $cols   = $meta->{cols};
   foreach my $key ( keys %$cols ) {
      my $info = $cols->{$key}
         or die "Column '$key' doesn't exist in $tbl";
      die "No func defined for '$key' in $tbl"
         unless $info->{func};
      eval {
         $result->{$key} = $info->{func}->($set, $cur, $pre)
      };
      if ( $EVAL_ERROR ) {
         if ( $config{debug}->{val} ) {
            die $EVAL_ERROR;
         }
         $result->{$key} = $info->{num} ? 0 : '';
      }
   }
   return $result;
}

# get_full_processlist {{{3
sub get_full_processlist {
   my @cxns = @_;
   my @result;
   foreach my $cxn ( @cxns ) {
      my $stmt = do_stmt($cxn, 'PROCESSLIST') or next;
      my $arr  = $stmt->fetchall_arrayref({});
      push @result, map { $_->{cxn} = $cxn; $_ } @$arr;
   }
   return @result;
}

# get_open_tables {{{3
sub get_open_tables {
   my @cxns = @_;
   my @result;
   foreach my $cxn ( @cxns ) {
      my $stmt = do_stmt($cxn, 'OPEN_TABLES') or next;
      my $arr  = $stmt->fetchall_arrayref({});
      push @result, map { $_->{cxn} = $cxn; $_ } @$arr;
   }
   return @result;
}

# get_innodb_status {{{3
sub get_innodb_status {
   my ( $cxns, $addl_sections ) = @_;
   if ( !$config{skip_innodb}->{val} && !$info_gotten{innodb_status}++ ) {

      # Determine which sections need to be parsed
      my %sections_required =
         map  { $tbl_meta{$_}->{innodb} => 1 }
         grep { $_ && $tbl_meta{$_}->{innodb} }
         get_visible_tables();

      # Add in any other sections the caller requested.
      foreach my $sec ( @$addl_sections ) {
         $sections_required{$sec} = 1;
      }

      foreach my $cxn ( @$cxns ) {
         my $innodb_status_text;

         if ( $file ) { # Try to fetch status text from the file.
            my @stat = stat($file);

            # Initialize the file.
            if ( !$file_mtime ) {
               # Initialize to 130k from the end of the file (because the limit
               # on the size of innodb status is 128k even with Google's patches)
               # and try to grab the last status from the file.
               sysseek($file, (-128 * 1_024), 2);
            }

            # Read from the file.
            my $buffer;
            if ( !$file_mtime || $file_mtime != $stat[9] ) {
               $file_data = '';
               while ( sysread($file, $buffer, 4096) ) {
                  $file_data .= $buffer;
               }
               $file_mtime = $stat[9];
            }

            # Delete everything but the last InnoDB status text from the file.
            $file_data =~ s/\A.*(?=^=====================================\n...... ........ INNODB MONITOR OUTPUT)//ms;
            $innodb_status_text = $file_data;
         }

         else {
            my $stmt = do_stmt($cxn, 'INNODB_STATUS') or next;
            $innodb_status_text = $stmt->fetchrow_hashref()->{status};
         }

         next unless $innodb_status_text
            && substr($innodb_status_text, 0, 100) =~ m/INNODB MONITOR OUTPUT/;

         # Parse and merge into %vars storage
         my %innodb_status = (
            $innodb_parser->get_status_hash(
               $innodb_status_text,
               $config{debug}->{val},
               \%sections_required,
               0, # don't parse full lock information
            )
         );
         if ( !$innodb_status{IB_got_all} && $config{auto_wipe_dl}->{val} ) {
            clear_deadlock($cxn);
         }

         # Merge using a hash slice, which is the fastest way
         $vars{$cxn}->{$clock} ||= {};
         my $hash = $vars{$cxn}->{$clock};
         @{$hash}{ keys %innodb_status } = values %innodb_status;
         $hash->{cxn} = $cxn;
         $hash->{Uptime_hires} ||= get_uptime($cxn);
      }
   }
}

# clear_deadlock {{{3
sub clear_deadlock {
   my ( $cxn ) = @_;
   return if $clearing_deadlocks++;
   my $tbl = $connections{$cxn}->{dl_table};
   return unless $tbl;

   eval {
      # Set up the table for creating a deadlock.
      my $engine = version_ge($dbhs{$cxn}->{dbh}, '4.1.2') ? 'engine' : 'type';
      return unless do_query($cxn, "drop table if exists $tbl");
      return unless do_query($cxn, "create table $tbl(a int) $engine=innodb");
      return unless do_query($cxn, "delete from $tbl");
      return unless do_query($cxn, "insert into $tbl(a) values(0), (1)");
      return unless do_query($cxn, "commit"); # Or the children will block against the parent

      # Fork off two children to deadlock against each other.
      my %children;
      foreach my $child ( 0..1 ) {
         my $pid = fork();
         if ( defined($pid) && $pid == 0 ) { # I am a child
            deadlock_thread( $child, $tbl, $cxn );
         }
         elsif ( !defined($pid) ) {
            die("Unable to fork for clearing deadlocks!\n");
         }
         # I already exited if I'm a child, so I'm the parent.
         $children{$child} = $pid;
      }

      # Wait for the children to exit.
      foreach my $child ( keys %children ) {
         my $pid = waitpid($children{$child}, 0);
      }

      # Clean up.
      do_query($cxn, "drop table $tbl");
   };
   if ( $EVAL_ERROR ) {
      print $EVAL_ERROR;
      pause();
   }

   $clearing_deadlocks = 0;
}

sub get_master_logs {
   my @cxns = @_;
   my @result;
   if ( !$info_gotten{master_logs}++ ) {
      foreach my $cxn ( @cxns ) {
         my $stmt = do_stmt($cxn, 'SHOW_MASTER_LOGS') or next;
         push @result, @{$stmt->fetchall_arrayref({})};
      }
   }
   return @result;
}

# get_master_slave_status {{{3
sub get_master_slave_status {
   my @cxns = @_;
   if ( !$info_gotten{replication_status}++ ) {
      foreach my $cxn ( @cxns ) {
         $vars{$cxn}->{$clock} ||= {};
         my $vars = $vars{$cxn}->{$clock};
         $vars->{cxn} = $cxn;

         my $stmt = do_stmt($cxn, 'SHOW_MASTER_STATUS') or next;
         my $res = $stmt->fetchall_arrayref({})->[0];
         @{$vars}{ keys %$res } = values %$res;
         $stmt = do_stmt($cxn, 'SHOW_SLAVE_STATUS') or next;
         $res = $stmt->fetchall_arrayref({})->[0];
         @{$vars}{ keys %$res } = values %$res;
         $vars->{Uptime_hires} ||= get_uptime($cxn);
      }
   }
}

sub is_func {
   my ( $word ) = @_;
   return defined(&$word)
      || eval "my \$x= sub { $word  }; 1"
      || $EVAL_ERROR !~ m/^Bareword/;
}

# Documentation {{{1
# ############################################################################
# I put this last as per the Dog book.
# ############################################################################
=pod

=head1 NAME

innotop - MySQL and InnoDB transaction/status monitor.

=head1 SYNOPSIS

To monitor servers normally:

 innotop

To monitor InnoDB status information from a file:

 innotop /var/log/mysql/mysqld.err

To run innotop non-interactively in a pipe-and-filter configuration:

 innotop --count 5 -d 1 -n

To monitor a database on another system using a particular username and password:

 innotop -u <username> -p <password> -h <hostname>

=head1 DESCRIPTION

innotop monitors MySQL servers.  Each of its modes shows you a different aspect
of what's happening in the server.  For example, there's a mode for monitoring
replication, one for queries, and one for transactions.  innotop refreshes its
data periodically, so you see an updating view.

innotop has lots of features for power users, but you can start and run it with
virtually no configuration.  If you're just getting started, see
L<"QUICK-START">.  Press '?' at any time while running innotop for
context-sensitive help.

=head1 QUICK-START

To start innotop, open a terminal or command prompt.  If you have installed
innotop on your system, you should be able to just type "innotop" and press
Enter; otherwise, you will need to change to innotop's directory and type "perl
innotop".

With no options specified, innotop will attempt to connect to a MySQL server on
localhost using mysql_read_default_group=client for other connection
parameters.  If you need to specify a different username and password, use the
-u and -p options, respectively.  To monitor a MySQL database on another
host, use the -h option.

After you've connected, innotop should show you something like the following:

 [RO] Query List (? for help) localhost, 01:11:19, 449.44 QPS, 14/7/163 con/run
 
 CXN        When   Load  QPS    Slow  QCacheHit  KCacheHit  BpsIn    BpsOut 
 localhost  Total  0.00  1.07k   697      0.00%     98.17%  476.83k  242.83k

 CXN        Cmd    ID         User  Host      DB   Time   Query
 localhost  Query  766446598  test  10.0.0.1  foo  00:02  INSERT INTO table (


(This sample is truncated at the right so it will fit on a terminal when running
'man innotop')

If your server is busy, you'll see more output.  Notice the first line on the
screen, which tells you that readonly is set to true ([RO]), what mode you're
in and what server you're connected to.  You can change to other modes with
keystrokes; press 'T' to switch to a list of InnoDB transactions, for example.

Press the '?' key to see what keys are active in the current mode.  You can
press any of these keys and innotop will either take the requested action or
prompt you for more input.  If your system has Term::ReadLine support, you can
use TAB and other keys to auto-complete and edit input.

To quit innotop, press the 'q' key.

=head1 OPTIONS

innotop is mostly configured via its configuration file, but some of the
configuration options can come from the command line.  You can also specify a
file to monitor for InnoDB status output; see L<"MONITORING A FILE"> for more
details.

You can negate some options by prefixing the option name with --no.  For
example, --noinc (or --no-inc) negates L<"--inc">.

=over

=item --color

Enable or disable terminal coloring.  Corresponds to the L<"color"> config file
setting.

=item --config

Specifies a configuration file to read.  This option is non-sticky, that is to
say it does not persist to the configuration file itself.

=item --count

Refresh only the specified number of times (ticks) before exiting.  Each refresh
is a pause for L<"interval"> seconds, followed by requesting data from MySQL
connections and printing it to the terminal.

=item --delay

Specifies the amount of time to pause between ticks (refreshes).  Corresponds to
the configuration option L<"interval">.

=item --help

Print a summary of command-line usage and exit.

=item --host

Host to connect to.

=item --inc

Specifies whether innotop should display absolute numbers or relative numbers
(offsets from their previous values).  Corresponds to the configuration option
L<"status_inc">.

=item --mode

Specifies the mode in which innotop should start.  Corresponds to the
configuration option L<"mode">.

=item --nonint

Enable non-interactive operation.  See L<"NON-INTERACTIVE OPERATION"> for more.

=item --password

Password to use for connection.

=item --port

Port to use for connection.

=item --skipcentral

Don't read the central configuration file.

=item --user

User to use for connection.

=item --version

Output version information and exit.

=item --write

Sets the configuration option L<"readonly"> to 0, making innotop write the
running configuration to ~/.innotop/innotop.conf on exit, if no configuration
file was loaded at start-up.

=back

=head1 HOTKEYS

innotop is interactive, and you control it with key-presses.

=over

=item *

Uppercase keys switch between modes.

=item *

Lowercase keys initiate some action within the current mode.

=item *

Other keys do something special like change configuration or show the
innotop license.

=back

Press '?' at any time to see the currently active keys and what they do.

=head1 MODES

Each of innotop's modes retrieves and displays a particular type of data from
the servers you're monitoring.  You switch between modes with uppercase keys.
The following is a brief description of each mode, in alphabetical order.  To
switch to the mode, press the key listed in front of its heading in the
following list:

=over

=item B: InnoDB Buffers

This mode displays information about the InnoDB buffer pool, page statistics,
insert buffer, and adaptive hash index.  The data comes from SHOW INNODB STATUS.

This mode contains the L<"buffer_pool">, L<"page_statistics">,
L<"insert_buffers">, and L<"adaptive_hash_index"> tables by default.

=item C: Command Summary

This mode is similar to mytop's Command Summary mode.  It shows the
L<"cmd_summary"> table, which looks something like the following:

 Command Summary (? for help) localhost, 25+07:16:43, 2.45 QPS, 3 thd, 5.0.40
 _____________________ Command Summary _____________________
 Name                    Value    Pct     Last Incr  Pct    
 Select_scan             3244858  69.89%          2  100.00%
 Select_range            1354177  29.17%          0    0.00%
 Select_full_join          39479   0.85%          0    0.00%
 Select_full_range_join     4097   0.09%          0    0.00%
 Select_range_check            0   0.00%          0    0.00%

The command summary table is built by extracting variables from
L<"STATUS_VARIABLES">.  The variables must be numeric and must match the prefix
given by the L<"cmd_filter"> configuration variable.  The variables are then
sorted by value descending and compared to the last variable, as shown above.
The percentage columns are percentage of the total of all variables in the
table, so you can see the relative weight of the variables.

The example shows what you see if the prefix is "Select_".  The default
prefix is "Com_".  You can choose a prefix with the 's' key.

It's rather like running SHOW VARIABLES LIKE "prefix%" with memory and
nice formatting.

Values are aggregated across all servers.  The Pct columns are not correctly
aggregated across multiple servers.  This is a known limitation of the grouping
algorithm that may be fixed in the future.

=item D: InnoDB Deadlocks

This mode shows the transactions involved in the last InnoDB deadlock.  A second
table shows the locks each transaction held and waited for.  A deadlock is
caused by a cycle in the waits-for graph, so there should be two locks held and
one waited for unless the deadlock information is truncated.

InnoDB puts deadlock information before some other information in the SHOW
INNODB STATUS output.  If there are a lot of locks, the deadlock information can
grow very large, and there is a limit on the size of the SHOW INNODB
STATUS output.  A large deadlock can fill the entire output, or even be
truncated, and prevent you from seeing other information at all.  If you are
running innotop in another mode, for example T mode, and suddenly you don't see
anything, you might want to check and see if a deadlock has wiped out the data
you need.

If it has, you can create a small deadlock to replace the large one.  Use the
'w' key to 'wipe' the large deadlock with a small one.  This will not work
unless you have defined a deadlock table for the connection (see L<"SERVER
CONNECTIONS">).

You can also configure innotop to automatically detect when a large deadlock
needs to be replaced with a small one (see L<"auto_wipe_dl">).

This mode displays the L<"deadlock_transactions"> and L<"deadlock_locks"> tables
by default.

=item F: InnoDB Foreign Key Errors

This mode shows the last InnoDB foreign key error information, such as the
table where it happened, when and who and what query caused it, and so on.

InnoDB has a huge variety of foreign key error messages, and many of them are
just hard to parse.  innotop doesn't always do the best job here, but there's
so much code devoted to parsing this messy, unparseable output that innotop is
likely never to be perfect in this regard.  If innotop doesn't show you what
you need to see, just look at the status text directly.

This mode displays the L<"fk_error"> table by default.

=item I: InnoDB I/O Info

This mode shows InnoDB's I/O statistics, including the I/O threads, pending I/O,
file I/O miscellaneous, and log statistics.  It displays the L<"io_threads">,
L<"pending_io">, L<"file_io_misc">, and L<"log_statistics"> tables by default.

=item L: Locks

This mode shows information about current locks.  At the moment only InnoDB
locks are supported, and by default you'll only see locks for which transactions
are waiting.  This information comes from the TRANSACTIONS section of the InnoDB
status text.  If you have a very busy server, you may have frequent lock waits;
it helps to be able to see which tables and indexes are the "hot spot" for
locks.  If your server is running pretty well, this mode should show nothing.

You can configure MySQL and innotop to monitor not only locks for which a
transaction is waiting, but those currently held, too.  You can do this with the
InnoDB Lock Monitor (L<http://dev.mysql.com/doc/en/innodb-monitor.html>).  It's
not documented in the MySQL manual, but creating the lock monitor with the
following statement also affects the output of SHOW INNODB STATUS, which innotop
uses:

  CREATE TABLE innodb_lock_monitor(a int) ENGINE=what mode you're
in and what server you're connected to.  You can change to other modes with
keystrokes; press 'T' to switch to a list of InnoDB transactions, for example.

Press the '?' key to see what keys are active in the current mode.  You can
press any of these keys and innotop will either take the requested action or
prompt you for more input.  If your system has Term::ReadLine support, you can
use TAB and other keys to auto-complete and edit input.

To quit innotop, press the 'q' key.

=head1 OPTIONS

innotop is mostly configured via its configuration file, but some of the
configuration options can come from the command line.  You can also specify a
file to monitor for InnoDB status output; see L<"MONITORING A FILE"> for more
details.

You can negate some options by prefixing the option name with --no.  For
example, --noinc (or --no-inc) negates L<"--inc">.

=over

=item --color

Enable or disable terminal coloring.  Corresponds to the L<"color"> config file
setting.

=item --config

Specifies a configuration file to read.  This option is non-sticky, that is to
say it does not persist to the configuration file itself.

=item --count

Refresh only the specified number of times (ticks) before exiting.  Each refresh
is a pause for L<"interval"> seconds, followed by requesting data from MySQL
connections and printing it to the terminal.

=item --delay

Specifies the amount of time to pause between ticks (refreshes).  Corresponds to
the configuration option L<"interval">.

=item --help

Print a summary of command-line usage and exit.

=item --host

Host to connect to.

=item --inc

Specifies whether innotop should display absolute numbers or relative numbers
(offsets from their previous values).  Corresponds to the configuration option
L<"status_inc">.

=item --mode

Specifies the mode in which innotop should start.  Corresponds to the
configuration option L<"mode">.

=item --nonint

Enable non-interactive operation.  See L<"NON-INTERACTIVE OPERATION"> for more.

=item --password

Password to use for connection.

=item --port

Port to use for connection.

=item --skipcentral

Don't read the central configuration file.

=item --user

User to use for connection.

=item --version

Output version information and exit.

=item --write

Sets the configuration option L<"readonly"> to 0, making innotop write the
running configuration to ~/.innotop/innotop.conf on exit, if no configuration
file was loaded at start-up.

=back

=head1 HOTKEYS

innotop is interactive, and you control it with key-presses.

=over

=item *

Uppercase keys switch between modes.

=item *

Lowercase keys initiate some action within the current mode.

=item *

Other keys do something special like change configuration or show the
innotop license.

=back

Press '?' at any time to see the currently active keys and what they do.

=head1 MODES

Each of innotop's modes retrieves and displays a particular type of data from
the servers you're monitoring.  You switch between modes with uppercase keys.
The following is a brief description of each mode, in alphabetical order.  To
switch to the mode, press the key listed in front of its heading in the
following list:

=over

=item B: InnoDB Buffers

This mode displays information about the InnoDB buffer pool, page statistics,
insert buffer, and adaptive hash index.  The data comes from SHOW INNODB STATUS.

This mode contains the L<"buffer_pool">, L<"page_statistics">,
L<"insert_buffers">, and L<"adaptive_hash_index"> tables by default.

=item C: Command Summary

This mode is similar to mytop's Command Summary mode.  It shows the
L<"cmd_summary"> table, which looks something like the following:

 Command Summary (? for help) localhost, 25+07:16:43, 2.45 QPS, 3 thd, 5.0.40
 _____________________ Command Summary _____________________
 Name                    Value    Pct     Last Incr  Pct    
 Select_scan             3244858  69.89%          2  100.00%
 Select_range            1354177  29.17%          0    0.00%
 Select_full_join          39479   0.85%          0    0.00%
 Select_full_range_join     4097   0.09%          0    0.00%
 Select_range_check            0   0.00%          0    0.00%

The command summary table is built by extracting variables from
L<"STATUS_VARIABLES">.  The variables must be numeric and must match the prefix
given by the L<"cmd_filter"> configuration variable.  The variables are then
sorted by value descending and compared to the last variable, as shown above.
The percentage columns are percentage of the total of all variables in the
table, so you can see the relative weight of the variables.

The example shows what you see if the prefix is "Select_".  The default
prefix is "Com_".  You can choose a prefix with the 's' key.

It's rather like running SHOW VARIABLES LIKE "prefix%" with memory and
nice formatting.

Values are aggregated across all servers.  The Pct columns are not correctly
aggregated across multiple servers.  This is a known limitation of the grouping
algorithm that may be fixed in the future.

=item D: InnoDB Deadlocks

This mode shows the transactions involved in the last InnoDB deadlock.  A second
table shows the locks each transaction held and waited for.  A deadlock is
caused by a cycle in the waits-for graph, so there should be two locks held and
one waited for unless the deadlock information is truncated.

InnoDB puts deadlock information before some other information in the SHOW
INNODB STATUS output.  If there are a lot of locks, the deadlock information can
grow very large, and there is a limit on the size of the SHOW INNODB
STATUS output.  A large deadlock can fill the entire output, or even be
truncated, and prevent you from seeing other information at all.  If you are
running innotop in another mode, for example T mode, and suddenly you don't see
anything, you might want to check and see if a deadlock has wiped out the data
you need.

If it has, you can create a small deadlock to replace the large one.  Use the
'w' key to 'wipe' the large deadlock with a small one.  This will not work
unless you have defined a deadlock table for the connection (see L<"SERVER
CONNECTIONS">).

You can also configure innotop to automatically detect when a large deadlock
needs to be replaced with a small one (see L<"auto_wipe_dl">).

This mode displays the L<"deadlock_transactions"> and L<"deadlock_locks"> tables
by default.

=item F: InnoDB Foreign Key Errors

This mode shows the last InnoDB foreign key error information, such as the
table where it happened, when and who and what query caused it, and so on.

InnoDB has a huge variety of foreign key error messages, and many of them are
just hard to parse.  innotop doesn't always do the best job here, but there's
so much code devoted to parsing this messy, unparseable output that innotop is
likely never to be perfect in this regard.  If innotop doesn't show you what
you need to see, just look at the status text directly.

This mode displays the L<"fk_error"> table by default.

=item I: InnoDB I/O Info

This mode shows InnoDB's I/O statistics, including the I/O threads, pending I/O,
file I/O miscellaneous, and log statistics.  It displays the L<"io_threads">,
L<"pending_io">, L<"file_io_misc">, and L<"log_statistics"> tables by default.

=item L: Locks

This mode shows information about current locks.  At the moment only InnoDB
locks are supported, and by default you'll only see locks for which transactions
are waiting.  This information comes from the TRANSACTIONS section of the InnoDB
status text.  If you have a very busy server, you may have frequent lock waits;
it helps to be able to see which tables and indexes are the "hot spot" for
locks.  If your server is running pretty well, this mode should show nothing.

You can configure MySQL and innotop to monitor not only locks for which a
transaction is waiting, but those currently held, too.  You can do this with the
InnoDB Lock Monitor (L<http://dev.mysql.com/doc/en/innodb-monitor.html>).  It's
not documented in the MySQL manual, but creating the lock monitor with the
following statement also affects the output of SHOW INNODB STATUS, which innotop
uses:

  CREATE TABLE innodb_lock_monitor(a int) ENGINE=what mode you're
in and what server you're connected to.  You can change to other modes with
keystrokes; press 'T' to switch to a list of InnoDB transactions, for example.

Press the '?' key to see what keys are active in the current mode.  You can
press any of these keys and innotop will either take the requested action or
prompt you for more input.  If your system has Term::ReadLine support, you can
use TAB and other keys to auto-complete and edit input.

To quit innotop, press the 'q' key.

=head1 OPTIONS

innotop is mostly configured via its configuration file, but some of the
configuration options can come from the command line.  You can also specify a
file to monitor for InnoDB status output; see L<"MONITORING A FILE"> for more
details.

You can negate some options by prefixing the option name with --no.  For
example, --noinc (or --no-inc) negates L<"--inc">.

=over

=item --color

Enable or disable terminal coloring.  Corresponds to the L<"color"> config file
setting.

=item --config

Specifies a configuration file to read.  This option is non-sticky, that is to
say it does not persist to the configuration file itself.

=item --count

Refresh only the specified number of times (ticks) before exiting.  Each refresh
is a pause for L<"interval"> seconds, followed by requesting data from MySQL
connections and printing it to the terminal.

=item --delay

Specifies the amount of time to pause between ticks (refreshes).  Corresponds to
the configuration option L<"interval">.

=item --help

Print a summary of command-line usage and exit.

=item --host

Host to connect to.

=item --inc

Specifies whether innotop should display absolute numbers or relative numbers
(offsets from their previous values).  Corresponds to the configuration option
L<"status_inc">.

=item --mode

Specifies the mode in which innotop should start.  Corresponds to the
configuration option L<"mode">.

=item --nonint

Enable non-interactive operation.  See L<"NON-INTERACTIVE OPERATION"> for more.

=item --password

Password to use for connection.

=item --port

Port to use for connection.

=item --skipcentral

Don't read the central configuration file.

=item --user

User to use for connection.

=item --version

Output version information and exit.

=item --write

Sets the configuration option L<"readonly"> to 0, making innotop write the
running configuration to ~/.innotop/innotop.conf on exit, if no configuration
file was loaded at start-up.

=back

=head1 HOTKEYS

innotop is interactive, and you control it with key-presses.

=over

=item *

Uppercase keys switch between modes.

=item *

Lowercase keys initiate some action within the current mode.

=item *

Other keys do something special like change configuration or show the
innotop license.

=back

Press '?' at any time to see the currently active keys and what they do.

=head1 MODES

Each of innotop's modes retrieves and displays a particular type of data from
the servers you're monitoring.  You switch between modes with uppercase keys.
The following is a brief description of each mode, in alphabetical order.  To
switch to the mode, press the key listed in front of its heading in the
following list:

=over

=item B: InnoDB Buffers

This mode displays information about the InnoDB buffer pool, page statistics,
insert buffer, and adaptive hash index.  The data comes from SHOW INNODB STATUS.

This mode contains the L<"buffer_pool">, L<"page_statistics">,
L<"insert_buffers">, and L<"adaptive_hash_index"> tables by default.

=item C: Command Summary

This mode is similar to mytop's Command Summary mode.  It shows the
L<"cmd_summary"> table, which looks something like the following:

 Command Summary (? for help) localhost, 25+07:16:43, 2.45 QPS, 3 thd, 5.0.40
 _____________________ Command Summary _____________________
 Name                    Value    Pct     Last Incr  Pct    
 Select_scan             3244858  69.89%          2  100.00%
 Select_range            1354177  29.17%          0    0.00%
 Select_full_join          39479   0.85%          0    0.00%
 Select_full_range_join     4097   0.09%          0    0.00%
 Select_range_check            0   0.00%          0    0.00%

The command summary table is built by extracting variables from
L<"STATUS_VARIABLES">.  The variables must be numeric and must match the prefix
given by the L<"cmd_filter"> configuration variable.  The variables are then
sorted by value descending and compared to the last variable, as shown above.
The percentage columns are percentage of the total of all variables in the
table, so you can see the relative weight of the variables.

The example shows what you see if the prefix is "Select_".  The default
prefix is "Com_".  You can choose a prefix with the 's' key.

It's rather like running SHOW VARIABLES LIKE "prefix%" with memory and
nice formatting.

Values are aggregated across all servers.  The Pct columns are not correctly
aggregated across multiple servers.  This is a known limitation of the grouping
algorithm that may be fixed in the future.

=item D: InnoDB Deadlocks

This mode shows the transactions involved in the last InnoDB deadlock.  A second
table shows the locks each transaction held and waited for.  A deadlock is
caused by a cycle in the waits-for graph, so there should be two locks held and
one waited for unless the deadlock information is truncated.

InnoDB puts deadlock information before some other information in the SHOW
INNODB STATUS output.  If there are a lot of locks, the deadlock information can
grow very large, and there is a limit on the size of the SHOW INNODB
STATUS output.  A large deadlock can fill the entire output, or even be
truncated, and prevent you from seeing other information at all.  If you are
running innotop in another mode, for example T mode, and suddenly you don't see
anything, you might want to check and see if a deadlock has wiped out the data
you need.

If it has, you can create a small deadlock to replace the large one.  Use the
'w' key to 'wipe' the large deadlock with a small one.  This will not work
unless you have defined a deadlock table for the connection (see L<"SERVER
CONNECTIONS">).

You can also configure innotop to automatically detect when a large deadlock
needs to be replaced with a small one (see L<"auto_wipe_dl">).

This mode displays the L<"deadlock_transactions"> and L<"deadlock_locks"> tables
by default.

=item F: InnoDB Foreign Key Errors

This mode shows the last InnoDB foreign key error information, such as the
table where it happened, when and who and what query caused it, and so on.

InnoDB has a huge variety of foreign key error messages, and many of them are
just hard to parse.  innotop doesn't always do the best job here, but there's
so much code devoted to parsing this messy, unparseable output that innotop is
likely never to be perfect in this regard.  If innotop doesn't show you what
you need to see, just look at the status text directly.

This mode displays the L<"fk_error"> table by default.

=item I: InnoDB I/O Info

This mode shows InnoDB's I/O statistics, including the I/O threads, pending I/O,
file I/O miscellaneous, and log statistics.  It displays the L<"io_threads">,
L<"pending_io">, L<"file_io_misc">, and L<"log_statistics"> tables by default.

=item L: Locks

This mode shows information about current locks.  At the moment only InnoDB
locks are supported, and by default you'll only see locks for which transactions
are waiting.  This information comes from the TRANSACTIONS section of the InnoDB
status text.  If you have a very busy server, you may have frequent lock waits;
it helps to be able to see which tables and indexes are the "hot spot" for
locks.  If your server is running pretty well, this mode should show nothing.

You can configure MySQL and innotop to monitor not only locks for which a
transaction is waiting, but those currently held, too.  You can do this with the
InnoDB Lock Monitor (L<http://dev.mysql.com/doc/en/innodb-monitor.html>).  It's
not documented in the MySQL manual, but creating the lock monitor with the
following statement also affects the output of SHOW INNODB STATUS, which innotop
uses:

  CREATE TABLE innodb_lock_monitor(a int) ENGINE=what mode you're
in and what server you're connected to.  You can change to other modes with
keystrokes; press 'T' to switch to a list of InnoDB transactions, for example.

Press the '?' key to see what keys are active in the current mode.  You can
press any of these keys and innotop will either take the requested action or
prompt you for more input.  If your system has Term::ReadLine support, you can
use TAB and other keys to auto-complete and edit input.

To quit innotop, press the 'q' key.

=head1 OPTIONS

innotop is mostly configured via its configuration file, but some of the
configuration options can come from the command line.  You can also specify a
file to monitor for InnoDB status output; see L<"MONITORING A FILE"> for more
details.

You can negate some options by prefixing the option name with --no.  For
example, --noinc (or --no-inc) negates L<"--inc">.

=over

=item --color

Enable or disable terminal coloring.  Corresponds to the L<"color"> config file
setting.

=item --config

Specifies a configuration file to read.  This option is non-sticky, that is to
say it does not persist to the configuration file itself.

=item --count

Refresh only the specified number of times (ticks) before exiting.  Each refresh
is a pause for L<"interval"> seconds, followed by requesting data from MySQL
connections and printing it to the terminal.

=item --delay

Specifies the amount of time to pause between ticks (refreshes).  Corresponds to
the configuration option L<"interval">.

=item --help

Print a summary of command-line usage and exit.

=item --host

Host to connect to.

=item --inc

Specifies whether innotop should display absolute numbers or relative numbers
(offsets from their previous values).  Corresponds to the configuration option
L<"status_inc">.

=item --mode

Specifies the mode in which innotop should start.  Corresponds to the
configuration option L<"mode">.

=item --nonint

Enable non-interactive operation.  See L<"NON-INTERACTIVE OPERATION"> for more.

=item --password

Password to use for connection.

=item --port

Port to use for connection.

=item --skipcentral

Don't read the central configuration file.

=item --user

User to use for connection.

=item --version

Output version information and exit.

=item --write

Sets the configuration option L<"readonly"> to 0, making innotop write the
running configuration to ~/.innotop/innotop.conf on exit, if no configuration
file was loaded at start-up.

=back

=head1 HOTKEYS

innotop is interactive, and you control it with key-presses.

=over

=item *

Uppercase keys switch between modes.

=item *

Lowercase keys initiate some action within the current mode.

=item *

Other keys do something special like change configuration or show the
innotop license.

=back

Press '?' at any time to see the currently active keys and what they do.

=head1 MODES

Each of innotop's modes retrieves and displays a particular type of data from
the servers you're monitoring.  You switch between modes with uppercase keys.
The following is a brief description of each mode, in alphabetical order.  To
switch to the mode, press the key listed in front of its heading in the
following list:

=over

=item B: InnoDB Buffers

This mode displays information about the InnoDB buffer pool, page statistics,
insert buffer, and adaptive hash index.  The data comes from SHOW INNODB STATUS.

This mode contains the L<"buffer_pool">, L<"page_statistics">,
L<"insert_buffers">, and L<"adaptive_hash_index"> tables by default.

=item C: Command Summary

This mode is similar to mytop's Command Summary mode.  It shows the
L<"cmd_summary"> table, which looks something like the following:

 Command Summary (? for help) localhost, 25+07:16:43, 2.45 QPS, 3 thd, 5.0.40
 _____________________ Command Summary _____________________
 Name                    Value    Pct     Last Incr  Pct    
 Select_scan             3244858  69.89%          2  100.00%
 Select_range            1354177  29.17%          0    0.00%
 Select_full_join          39479   0.85%          0    0.00%
 Select_full_range_join     4097   0.09%          0    0.00%
 Select_range_check            0   0.00%          0    0.00%

The command summary table is built by extracting variables from
L<"STATUS_VARIABLES">.  The variables must be numeric and must match the prefix
given by the L<"cmd_filter"> configuration variable.  The variables are then
sorted by value descending and compared to the last variable, as shown above.
The percentage columns are percentage of the total of all variables in the
table, so you can see the relative weight of the variables.

The example shows what you see if the prefix is "Select_".  The default
prefix is "Com_".  You can choose a prefix with the 's' key.

It's rather like running SHOW VARIABLES LIKE "prefix%" with memory and
nice formatting.

Values are aggregated across all servers.  The Pct columns are not correctly
aggregated across multiple servers.  This is a known limitation of the grouping
algorithm that may be fixed in the future.

=item D: InnoDB Deadlocks

This mode shows the transactions involved in the last InnoDB deadlock.  A second
table shows the locks each transaction held and waited for.  A deadlock is
caused by a cycle in the waits-for graph, so there should be two locks held and
one waited for unless the deadlock information is truncated.

InnoDB puts deadlock information before some other information in the SHOW
INNODB STATUS output.  If there are a lot of locks, the deadlock information can
grow very large, and there is a limit on the size of the SHOW INNODB
STATUS output.  A large deadlock can fill the entire output, or even be
truncated, and prevent you from seeing other information at all.  If you are
running innotop in another mode, for example T mode, and suddenly you don't see
anything, you might want to check and see if a deadlock has wiped out the data
you need.

If it has, you can create a small deadlock to replace the large one.  Use the
'w' key to 'wipe' the large deadlock with a small one.  This will not work
unless you have defined a deadlock table for the connection (see L<"SERVER
CONNECTIONS">).

You can also configure innotop to automatically detect when a large deadlock
needs to be replaced with a small one (see L<"auto_wipe_dl">).

This mode displays the L<"deadlock_transactions"> and L<"deadlock_locks"> tables
by default.

=item F: InnoDB Foreign Key Errors

This mode shows the last InnoDB foreign key error information, such as the
table where it happened, when and who and what query caused it, and so on.

InnoDB has a huge variety of foreign key error messages, and many of them are
just hard to parse.  innotop doesn't always do the best job here, but there's
so much code devoted to parsing this messy, unparseable output that innotop is
likely never to be perfect in this regard.  If innotop doesn't show you what
you need to see, just look at the status text directly.

This mode displays the L<"fk_error"> table by default.

=item I: InnoDB I/O Info

This mode shows InnoDB's I/O statistics, including the I/O threads, pending I/O,
file I/O miscellaneous, and log statistics.  It displays the L<"io_threads">,
L<"pending_io">, L<"file_io_misc">, and L<"log_statistics"> tables by default.

=item L: Locks

This mode shows information about current locks.  At the moment only InnoDB
locks are supported, and by default you'll only see locks for which transactions
are waiting.  This information comes from the TRANSACTIONS section of the InnoDB
status text.  If you have a very busy server, you may have frequent lock waits;
it helps to be able to see which tables and indexes are the "hot spot" for
locks.  If your server is running pretty well, this mode should show nothing.

You can configure MySQL and innotop to monitor not only locks for which a
transaction is waiting, but those currently held, too.  You can do this with the
InnoDB Lock Monitor (L<http://dev.mysql.com/doc/en/innodb-monitor.html>).  It's
not documented in the MySQL manual, but creating the lock monitor with the
following statement also affects the output of SHOW INNODB STATUS, which innotop
uses:

  CREATE TABLE innodb_lock_monitor(a int) ENGINE=what mode you're
in and what server you're connected to.  You can change to other modes with
keystrokes; press 'T' to switch to a list of InnoDB transactions, for example.

Press the '?' key to see what keys are active in the current mode.  You can
press any of these keys and innotop will either take the requested action or
prompt you for more input.  If your system has Term::ReadLine support, you can
use TAB and other keys to auto-complete and edit input.

To quit innotop, press the 'q' key.

=head1 OPTIONS

innotop is mostly configured via its configuration file, but some of the
configuration options can come from the command line.  You can also specify a
file to monitor for InnoDB status output; see L<"MONITORING A FILE"> for more
details.

You can negate some options by prefixing the option name with --no.  For
example, --noinc (or --no-inc) negates L<"--inc">.

=over

=item --color

Enable or disable terminal coloring.  Corresponds to the L<"color"> config file
setting.

=item --config

Specifies a configuration file to read.  This option is non-sticky, that is to
say it does not persist to the configuration file itself.

=item --count

Refresh only the specified number of times (ticks) before exiting.  Each refresh
is a pause for L<"interval"> seconds, followed by requesting data from MySQL
connections and printing it to the terminal.

=item --delay

Specifies the amount of time to pause between ticks (refreshes).  Corresponds to
the configuration option L<"interval">.

=item --help

Print a summary of command-line usage and exit.

=item --host

Host to connect to.

=item --inc

Specifies whether innotop should display absolute numbers or relative numbers
(offsets from their previous values).  Corresponds to the configuration option
L<"status_inc">.

=item --mode

Specifies the mode in which innotop should start.  Corresponds to the
configuration option L<"mode">.

=item --nonint

Enable non-interactive operation.  See L<"NON-INTERACTIVE OPERATION"> for more.

=item --password

Password to use for connection.

=item --port

Port to use for connection.

=item --skipcentral

Don't read the central configuration file.

=item --user

User to use for connection.

=item --version

Output version information and exit.

=item --write

Sets the configuration option L<"readonly"> to 0, making innotop write the
running configuration to ~/.innotop/innotop.conf on exit, if no configuration
file was loaded at start-up.

=back

=head1 HOTKEYS

innotop is interactive, and you control it with key-presses.

=over

=item *

Uppercase keys switch between modes.

=item *

Lowercase keys initiate some action within the current mode.

=item *

Other keys do something special like change configuration or show the
innotop license.

=back

Press '?' at any time to see the currently active keys and what they do.

=head1 MODES

Each of innotop's modes retrieves and displays a particular type of data from
the servers you're monitoring.  You switch between modes with uppercase keys.
The following is a brief description of each mode, in alphabetical order.  To
switch to the mode, press the key listed in front of its heading in the
following list:

=over

=item B: InnoDB Buffers

This mode displays information about the InnoDB buffer pool, page statistics,
insert buffer, and adaptive hash index.  The data comes from SHOW INNODB STATUS.

This mode contains the L<"buffer_pool">, L<"page_statistics">,
L<"insert_buffers">, and L<"adaptive_hash_index"> tables by default.

=item C: Command Summary

This mode is similar to mytop's Command Summary mode.  It shows the
L<"cmd_summary"> table, which looks something like the following:

 Command Summary (? for help) localhost, 25+07:16:43, 2.45 QPS, 3 thd, 5.0.40
 _____________________ Command Summary _____________________
 Name                    Value    Pct     Last Incr  Pct    
 Select_scan             3244858  69.89%          2  100.00%
 Select_range            1354177  29.17%          0    0.00%
 Select_full_join          39479   0.85%          0    0.00%
 Select_full_range_join     4097   0.09%          0    0.00%
 Select_range_check            0   0.00%          0    0.00%

The command summary table is built by extracting variables from
L<"STATUS_VARIABLES">.  The variables must be numeric and must match the prefix
given by the L<"cmd_filter"> configuration variable.  The variables are then
sorted by value descending and compared to the last variable, as shown above.
The percentage columns are percentage of the total of all variables in the
table, so you can see the relative weight of the variables.

The example shows what you see if the prefix is "Select_".  The default
prefix is "Com_".  You can choose a prefix with the 's' key.

It's rather like running SHOW VARIABLES LIKE "prefix%" with memory and
nice formatting.

Values are aggregated across all servers.  The Pct columns are not correctly
aggregated across multiple servers.  This is a known limitation of the grouping
algorithm that may be fixed in the future.

=item D: InnoDB Deadlocks

This mode shows the transactions involved in the last InnoDB deadlock.  A second
table shows the locks each transaction held and waited for.  A deadlock is
caused by a cycle in the waits-for graph, so there should be two locks held and
one waited for unless the deadlock information is truncated.

InnoDB puts deadlock information before some other information in the SHOW
INNODB STATUS output.  If there are a lot of locks, the deadlock information can
grow very large, and there is a limit on the size of the SHOW INNODB
STATUS output.  A large deadlock can fill the entire output, or even be
truncated, and prevent you from seeing other information at all.  If you are
running innotop in another mode, for example T mode, and suddenly you don't see
anything, you might want to check and see if a deadlock has wiped out the data
you need.

If it has, you can create a small deadlock to replace the large one.  Use the
'w' key to 'wipe' the large deadlock with a small one.  This will not work
unless you have defined a deadlock table for the connection (see L<"SERVER
CONNECTIONS">).

You can also configure innotop to automatically detect when a large deadlock
needs to be replaced with a small one (see L<"auto_wipe_dl">).

This mode displays the L<"deadlock_transactions"> and L<"deadlock_locks"> tables
by default.

=item F: InnoDB Foreign Key Errors

This mode shows the last InnoDB foreign key error information, such as the
table where it happened, when and who and what query caused it, and so on.

InnoDB has a huge variety of foreign key error messages, and many of them are
just hard to parse.  innotop doesn't always do the best job here, but there's
so much code devoted to parsing this messy, unparseable output that innotop is
likely never to be perfect in this regard.  If innotop doesn't show you what
you need to see, just look at the status text directly.

This mode displays the L<"fk_error"> table by default.

=item I: InnoDB I/O Info

This mode shows InnoDB's I/O statistics, including the I/O threads, pending I/O,
file I/O miscellaneous, and log statistics.  It displays the L<"io_threads">,
L<"pending_io">, L<"file_io_misc">, and L<"log_statistics"> tables by default.

=item L: Locks

This mode shows information about current locks.  At the moment only InnoDB
locks are supported, and by default you'll only see locks for which transactions
are waiting.  This information comes from the TRANSACTIONS section of the InnoDB
status text.  If you have a very busy server, you may have frequent lock waits;
it helps to be able to see which tables and indexes are the "hot spot" for
locks.  If your server is running pretty well, this mode should show nothing.

You can configure MySQL and innotop to monitor not only locks for which a
transaction is waiting, but those currently held, too.  You can do this with the
InnoDB Lock Monitor (L<http://dev.mysql.com/doc/en/innodb-monitor.html>).  It's
not documented in the MySQL manual, but creating the lock monitor with the
following statement also affects the output of SHOW INNODB STATUS, which innotop
uses:

  CREATE TABLE innodb_lock_monitor(a int) ENGINE=what mode you're
in and what server you're connected to.  You can change to other modes with
keystrokes; press 'T' to switch to a list of InnoDB transactions, for example.

Press the '?' key to see what keys are active in the current mode.  You can
press any of these keys and innotop will either take the requested action or
prompt you for more input.  If your system has Term::ReadLine support, you can
use TAB and other keys to auto-complete and edit input.

To quit innotop, press the 'q' key.

=head1 OPTIONS

innotop is mostly configured via its configuration file, but some of the
configuration options can come from the command line.  You can also specify a
file to monitor for InnoDB status output; see L<"MONITORING A FILE"> for more
details.

You can negate some options by prefixing the option name with --no.  For
example, --noinc (or --no-inc) negates L<"--inc">.

=over

=item --color

Enable or disable terminal coloring.  Corresponds to the L<"color"> config file
setting.

=item --config

Specifies a configuration file to read.  This option is non-sticky, that is to
say it does not persist to the configuration file itself.

=item --count

Refresh only the specified number of times (ticks) before exiting.  Each refresh
is a pause for L<"interval"> seconds, followed by requesting data from MySQL
connections and printing it to the terminal.

=item --delay

Specifies the amount of time to pause between ticks (refreshes).  Corresponds to
the configuration option L<"interval">.

=item --help

Print a summary of command-line usage and exit.

=item --host

Host to connect to.

=item --inc

Specifies whether innotop should display absolute numbers or relative numbers
(offsets from their previous values).  Corresponds to the configuration option
L<"status_inc">.

=item --mode

Specifies the mode in which innotop should start.  Corresponds to the
configuration option L<"mode">.

=item --nonint

Enable non-interactive operation.  See L<"NON-INTERACTIVE OPERATION"> for more.

=item --password

Password to use for connection.

=item --port

Port to use for connection.

=item --skipcentral

Don't read the central configuration file.

=item --user

User to use for connection.

=item --version

Output version information and exit.

=item --write

Sets the configuration option L<"readonly"> to 0, making innotop write the
running configuration to ~/.innotop/innotop.conf on exit, if no configuration
file was loaded at start-up.

=back

=head1 HOTKEYS

innotop is interactive, and you control it with key-presses.

=over

=item *

Uppercase keys switch between modes.

=item *

Lowercase keys initiate some action within the current mode.

=item *

Other keys do something special like change configuration or show the
innotop license.

=back

Press '?' at any time to see the currently active keys and what they do.

=head1 MODES

Each of innotop's modes retrieves and displays a particular type of data from
the servers you're monitoring.  You switch between modes with uppercase keys.
The following is a brief description of each mode, in alphabetical order.  To
switch to the mode, press the key listed in front of its heading in the
following list:

=over

=item B: InnoDB Buffers

This mode displays information about the InnoDB buffer pool, page statistics,
insert buffer, and adaptive hash index.  The data comes from SHOW INNODB STATUS.

This mode contains the L<"buffer_pool">, L<"page_statistics">,
L<"insert_buffers">, and L<"adaptive_hash_index"> tables by default.

=item C: Command Summary

This mode is similar to mytop's Command Summary mode.  It shows the
L<"cmd_summary"> table, which looks something like the following:

 Command Summary (? for help) localhost, 25+07:16:43, 2.45 QPS, 3 thd, 5.0.40
 _____________________ Command Summary _____________________
 Name                    Value    Pct     Last Incr  Pct    
 Select_scan             3244858  69.89%          2  100.00%
 Select_range            1354177  29.17%          0    0.00%
 Select_full_join          39479   0.85%          0    0.00%
 Select_full_range_join     4097   0.09%          0    0.00%
 Select_range_check            0   0.00%          0    0.00%

The command summary table is built by extracting variables from
L<"STATUS_VARIABLES">.  The variables must be numeric and must match the prefix
given by the L<"cmd_filter"> configuration variable.  The variables are then
sorted by value descending and compared to the last variable, as shown above.
The percentage columns are percentage of the total of all variables in the
table, so you can see the relative weight of the variables.

The example shows what you see if the prefix is "Select_".  The default
prefix is "Com_".  You can choose a prefix with the 's' key.

It's rather like running SHOW VARIABLES LIKE "prefix%" with memory and
nice formatting.

Values are aggregated across all servers.  The Pct columns are not correctly
aggregated across multiple servers.  This is a known limitation of the grouping
algorithm that may be fixed in the future.

=item D: InnoDB Deadlocks

This mode shows the transactions involved in the last InnoDB deadlock.  A second
table shows the locks each transaction held and waited for.  A deadlock is
caused by a cycle in the waits-for graph, so there should be two locks held and
one waited for unless the deadlock information is truncated.

InnoDB puts deadlock information before some other information in the SHOW
INNODB STATUS output.  If there are a lot of locks, the deadlock information can
grow very large, and there is a limit on the size of the SHOW INNODB
STATUS output.  A large deadlock can fill the entire output, or even be
truncated, and prevent you from seeing other information at all.  If you are
running innotop in another mode, for example T mode, and suddenly you don't see
anything, you might want to check and see if a deadlock has wiped out the data
you need.

If it has, you can create a small deadlock to replace the large one.  Use the
'w' key to 'wipe' the large deadlock with a small one.  This will not work
unless you have defined a deadlock table for the connection (see L<"SERVER
CONNECTIONS">).

You can also configure innotop to automatically detect when a large deadlock
needs to be replaced with a small one (see L<"auto_wipe_dl">).

This mode displays the L<"deadlock_transactions"> and L<"deadlock_locks"> tables
by default.

=item F: InnoDB Foreign Key Errors

This mode shows the last InnoDB foreign key error information, such as the
table where it happened, when and who and what query caused it, and so on.

InnoDB has a huge variety of foreign key error messages, and many of them are
just hard to parse.  innotop doesn't always do the best job here, but there's
so much code devoted to parsing this messy, unparseable output that innotop is
likely never to be perfect in this regard.  If innotop doesn't show you what
you need to see, just look at the status text directly.

This mode displays the L<"fk_error"> table by default.

=item I: InnoDB I/O Info

This mode shows InnoDB's I/O statistics, including the I/O threads, pending I/O,
file I/O miscellaneous, and log statistics.  It displays the L<"io_threads">,
L<"pending_io">, L<"file_io_misc">, and L<"log_statistics"> tables by default.

=item L: Locks

This mode shows information about current locks.  At the moment only InnoDB
locks are supported, and by default you'll only see locks for which transactions
are waiting.  This information comes from the TRANSACTIONS section of the InnoDB
status text.  If you have a very busy server, you may have frequent lock waits;
it helps to be able to see which tables and indexes are the "hot spot" for
locks.  If your server is running pretty well, this mode should show nothing.

You can configure MySQL and innotop to monitor not only locks for which a
transaction is waiting, but those currently held, too.  You can do this with the
InnoDB Lock Monitor (L<http://dev.mysql.com/doc/en/innodb-monitor.html>).  It's
not documented in the MySQL manual, but creating the lock monitor with the
following statement also affects the output of SHOW INNODB STATUS, which innotop
uses:

  CREATE TABLE innodb_lock_monitor(a int) ENGINE=what mode you're
in and what server you're connected to.  You can change to other modes with
keystrokes; press 'T' to switch to a list of InnoDB transactions, for example.

Press the '?' key to see what keys are active in the current mode.  You can
press any of these keys and innotop will either take the requested action or
prompt you for more input.  If your system has Term::ReadLine support, you can
use TAB and other keys to auto-complete and edit input.

To quit innotop, press the 'q' key.

=head1 OPTIONS

innotop is mostly configured via its configuration file, but some of the
configuration options can come from the command line.  You can also specify a
file to monitor for InnoDB status output; see L<"MONITORING A FILE"> for more
details.

You can negate some options by prefixing the option name with --no.  For
example, --noinc (or --no-inc) negates L<"--inc">.

=over

=item --color

Enable or disable terminal coloring.  Corresponds to the L<"color"> config file
setting.

=item --config

Specifies a configuration file to read.  This option is non-sticky, that is to
say it does not persist to the configuration file itself.

=item --count

Refresh only the specified number of times (ticks) before exiting.  Each refresh
is a pause for L<"interval"> seconds, followed by requesting data from MySQL
connections and printing it to the terminal.

=item --delay

Specifies the amount of time to pause between ticks (refreshes).  Corresponds to
the configuration option L<"interval">.

=item --help

Print a summary of command-line usage and exit.

=item --host

Host to connect to.

=item --inc

Specifies whether innotop should display absolute numbers or relative numbers
(offsets from their previous values).  Corresponds to the configuration option
L<"status_inc">.

=item --mode

Specifies the mode in which innotop should start.  Corresponds to the
configuration option L<"mode">.

=item --nonint

Enable non-interactive operation.  See L<"NON-INTERACTIVE OPERATION"> for more.

=item --password

Password to use for connection.

=item --port

Port to use for connection.

=item --skipcentral

Don't read the central configuration file.

=item --user

User to use for connection.

=item --version

Output version information and exit.

=item --write

Sets the configuration option L<"readonly"> to 0, making innotop write the
running configuration to ~/.innotop/innotop.conf on exit, if no configuration
file was loaded at start-up.

=back

=head1 HOTKEYS

innotop is interactive, and you control it with key-presses.

=over

=item *

Uppercase keys switch between modes.

=item *

Lowercase keys initiate some action within the current mode.

=item *

Other keys do something special like change configuration or show the
innotop license.

=back

Press '?' at any time to see the currently active keys and what they do.

=head1 MODES

Each of innotop's modes retrieves and displays a particular type of data from
the servers you're monitoring.  You switch between modes with uppercase keys.
The following is a brief description of each mode, in alphabetical order.  To
switch to the mode, press the key listed in front of its heading in the
following list:

=over

=item B: InnoDB Buffers

This mode displays information about the InnoDB buffer pool, page statistics,
insert buffer, and adaptive hash index.  The data comes from SHOW INNODB STATUS.

This mode contains the L<"buffer_pool">, L<"page_statistics">,
L<"insert_buffers">, and L<"adaptive_hash_index"> tables by default.

=item C: Command Summary

This mode is similar to mytop's Command Summary mode.  It shows the
L<"cmd_summary"> table, which looks something like the following:

 Command Summary (? for help) localhost, 25+07:16:43, 2.45 QPS, 3 thd, 5.0.40
 _____________________ Command Summary _____________________
 Name                    Value    Pct     Last Incr  Pct    
 Select_scan             3244858  69.89%          2  100.00%
 Select_range            1354177  29.17%          0    0.00%
 Select_full_join          39479   0.85%          0    0.00%
 Select_full_range_join     4097   0.09%          0    0.00%
 Select_range_check            0   0.00%          0    0.00%

The command summary table is built by extracting variables from
L<"STATUS_VARIABLES">.  The variables must be numeric and must match the prefix
given by the L<"cmd_filter"> configuration variable.  The variables are then
sorted by value descending and compared to the last variable, as shown above.
The percentage columns are percentage of the total of all variables in the
table, so you can see the relative weight of the variables.

The example shows what you see if the prefix is "Select_".  The default
prefix is "Com_".  You can choose a prefix with the 's' key.

It's rather like running SHOW VARIABLES LIKE "prefix%" with memory and
nice formatting.

Values are aggregated across all servers.  The Pct columns are not correctly
aggregated across multiple servers.  This is a known limitation of the grouping
algorithm that may be fixed in the future.

=item D: InnoDB Deadlocks

This mode shows the transactions involved in the last InnoDB deadlock.  A second
table shows the locks each transaction held and waited for.  A deadlock is
caused by a cycle in the waits-for graph, so there should be two locks held and
one waited for unless the deadlock information is truncated.

InnoDB puts deadlock information before some other information in the SHOW
INNODB STATUS output.  If there are a lot of locks, the deadlock information can
grow very large, and there is a limit on the size of the SHOW INNODB
STATUS output.  A large deadlock can fill the entire output, or even be
truncated, and prevent you from seeing other information at all.  If you are
running innotop in another mode, for example T mode, and suddenly you don't see
anything, you might want to check and see if a deadlock has wiped out the data
you need.

If it has, you can create a small deadlock to replace the large one.  Use the
'w' key to 'wipe' the large deadlock with a small one.  This will not work
unless you have defined a deadlock table for the connection (see L<"SERVER
CONNECTIONS">).

You can also configure innotop to automatically detect when a large deadlock
needs to be replaced with a small one (see L<"auto_wipe_dl">).

This mode displays the L<"deadlock_transactions"> and L<"deadlock_locks"> tables
by default.

=item F: InnoDB Foreign Key Errors

This mode shows the last InnoDB foreign key error information, such as the
table where it happened, when and who and what query caused it, and so on.

InnoDB has a huge variety of foreign key error messages, and many of them are
just hard to parse.  innotop doesn't always do the best job here, but there's
so much code devoted to parsing this messy, unparseable output that innotop is
likely never to be perfect in this regard.  If innotop doesn't show you what
you need to see, just look at the status text directly.

This mode displays the L<"fk_error"> table by default.

=item I: InnoDB I/O Info

This mode shows InnoDB's I/O statistics, including the I/O threads, pending I/O,
file I/O miscellaneous, and log statistics.  It displays the L<"io_threads">,
L<"pending_io">, L<"file_io_misc">, and L<"log_statistics"> tables by default.

=item L: Locks

This mode shows information about current locks.  At the moment only InnoDB
locks are supported, and by default you'll only see locks for which transactions
are waiting.  This information comes from the TRANSACTIONS section of the InnoDB
status text.  If you have a very busy server, you may have frequent lock waits;
it helps to be able to see which tables and indexes are the "hot spot" for
locks.  If your server is running pretty well, this mode should show nothing.

You can configure MySQL and innotop to monitor not only locks for which a
transaction is waiting, but those currently held, too.  You can do this with the
InnoDB Lock Monitor (L<http://dev.mysql.com/doc/en/innodb-monitor.html>).  It's
not documented in the MySQL manual, but creating the lock monitor with the
following statement also affects the output of SHOW INNODB STATUS, which innotop
uses:

  CREATE TABLE innodb_lock_monitor(a int) ENGINE=what mode you're
in and what server you're connected to.  You can change to other modes with
keystrokes; press 'T' to switch to a list of InnoDB transactions, for example.

Press the '?' key to see what keys are active in the current mode.  You can
press any of these keys and innotop will either take the requested action or
prompt you for more input.  If your system has Term::ReadLine support, you can
use TAB and other keys to auto-complete and edit input.

To quit innotop, press the 'q' key.

=head1 OPTIONS

innotop is mostly configured via its configuration file, but some of the
configuration options can come from the command line.  You can also specify a
file to monitor for InnoDB status output; see L<"MONITORING A FILE"> for more
details.

You can negate some options by prefixing the option name with --no.  For
example, --noinc (or --no-inc) negates L<"--inc">.

=over

=item --color

Enable or disable terminal coloring.  Corresponds to the L<"color"> config file
setting.

=item --config

Specifies a configuration file to read.  This option is non-sticky, that is to
say it does not persist to the configuration file itself.

=item --count

Refresh only the specified number of times (ticks) before exiting.  Each refresh
is a pause for L<"interval"> seconds, followed by requesting data from MySQL
connections and printing it to the terminal.

=item --delay

Specifies the amount of time to pause between ticks (refreshes).  Corresponds to
the configuration option L<"interval">.

=item --help

Print a summary of command-line usage and exit.

=item --host

Host to connect to.

=item --inc

Specifies whether innotop should display absolute numbers or relative numbers
(offsets from their previous values).  Corresponds to the configuration option
L<"status_inc">.

=item --mode

Specifies the mode in which innotop should start.  Corresponds to the
configuration option L<"mode">.

=item --nonint

Enable non-interactive operation.  See L<"NON-INTERACTIVE OPERATION"> for more.

=item --password

Password to use for connection.

=item --port

Port to use for connection.

=item --skipcentral

Don't read the central configuration file.

=item --user

User to use for connection.

=item --version

Output version information and exit.

=item --write

Sets the configuration option L<"readonly"> to 0, making innotop write the
running configuration to ~/.innotop/innotop.conf on exit, if no configuration
file was loaded at start-up.

=back

=head1 HOTKEYS

innotop is interactive, and you control it with key-presses.

=over

=item *

Uppercase keys switch between modes.

=item *

Lowercase keys initiate some action within the current mode.

=item *

Other keys do something special like change configuration or show the
innotop license.

=back

Press '?' at any time to see the currently active keys and what they do.

=head1 MODES

Each of innotop's modes retrieves and displays a particular type of data from
the servers you're monitoring.  You switch between modes with uppercase keys.
The following is a brief description of each mode, in alphabetical order.  To
switch to the mode, press the key listed in front of its heading in the
following list:

=over

=item B: InnoDB Buffers

This mode displays information about the InnoDB buffer pool, page statistics,
insert buffer, and adaptive hash index.  The data comes from SHOW INNODB STATUS.

This mode contains the L<"buffer_pool">, L<"page_statistics">,
L<"insert_buffers">, and L<"adaptive_hash_index"> tables by default.

=item C: Command Summary

This mode is similar to mytop's Command Summary mode.  It shows the
L<"cmd_summary"> table, which looks something like the following:

 Command Summary (? for help) localhost, 25+07:16:43, 2.45 QPS, 3 thd, 5.0.40
 _____________________ Command Summary _____________________
 Name                    Value    Pct     Last Incr  Pct    
 Select_scan             3244858  69.89%          2  100.00%
 Select_range            1354177  29.17%          0    0.00%
 Select_full_join          39479   0.85%          0    0.00%
 Select_full_range_join     4097   0.09%          0    0.00%
 Select_range_check            0   0.00%          0    0.00%

The command summary table is built by extracting variables from
L<"STATUS_VARIABLES">.  The variables must be numeric and must match the prefix
given by the L<"cmd_filter"> configuration variable.  The variables are then
sorted by value descending and compared to the last variable, as shown above.
The percentage columns are percentage of the total of all variables in the
table, so you can see the relative weight of the variables.

The example shows what you see if the prefix is "Select_".  The default
prefix is "Com_".  You can choose a prefix with the 's' key.

It's rather like running SHOW VARIABLES LIKE "prefix%" with memory and
nice formatting.

Values are aggregated across all servers.  The Pct columns are not correctly
aggregated across multiple servers.  This is a known limitation of the grouping
algorithm that may be fixed in the future.

=item D: InnoDB Deadlocks

This mode shows the transactions involved in the last InnoDB deadlock.  A second
table shows the locks each transaction held and waited for.  A deadlock is
caused by a cycle in the waits-for graph, so there should be two locks held and
one waited for unless the deadlock information is truncated.

InnoDB puts deadlock information before some other information in the SHOW
INNODB STATUS output.  If there are a lot of locks, the deadlock information can
grow very large, and there is a limit on the size of the SHOW INNODB
STATUS output.  A large deadlock can fill the entire output, or even be
truncated, and prevent you from seeing other information at all.  If you are
running innotop in another mode, for example T mode, and suddenly you don't see
anything, you might want to check and see if a deadlock has wiped out the data
you need.

If it has, you can create a small deadlock to replace the large one.  Use the
'w' key to 'wipe' the large deadlock with a small one.  This will not work
unless you have defined a deadlock table for the connection (see L<"SERVER
CONNECTIONS">).

You can also configure innotop to automatically detect when a large deadlock
needs to be replaced with a small one (see L<"auto_wipe_dl">).

This mode displays the L<"deadlock_transactions"> and L<"deadlock_locks"> tables
by default.

=item F: InnoDB Foreign Key Errors

This mode shows the last InnoDB foreign key error information, such as the
table where it happened, when and who and what query caused it, and so on.

InnoDB has a huge variety of foreign key error messages, and many of them are
just hard to parse.  innotop doesn't always do the best job here, but there's
so much code devoted to parsing this messy, unparseable output that innotop is
likely never to be perfect in this regard.  If innotop doesn't show you what
you need to see, just look at the status text directly.

This mode displays the L<"fk_error"> table by default.

=item I: InnoDB I/O Info

This mode shows InnoDB's I/O statistics, including the I/O threads, pending I/O,
file I/O miscellaneous, and log statistics.  It displays the L<"io_threads">,
L<"pending_io">, L<"file_io_misc">, and L<"log_statistics"> tables by default.

=item L: Locks

This mode shows information about current locks.  At the moment only InnoDB
locks are supported, and by default you'll only see locks for which transactions
are waiting.  This information comes from the TRANSACTIONS section of the InnoDB
status text.  If you have a very busy server, you may have frequent lock waits;
it helps to be able to see which tables and indexes are the "hot spot" for
locks.  If your server is running pretty well, this mode should show nothing.

You can configure MySQL and innotop to monitor not only locks for which a
transaction is waiting, but those currently held, too.  You can do this with the
InnoDB Lock Monitor (L<http://dev.mysql.com/doc/en/innodb-monitor.html>).  It's
not documented in the MySQL manual, but creating the lock monitor with the
following statement also affects the output of SHOW INNODB STATUS, which innotop
uses:

  CREATE TABLE innodb_lock_monitor(a int) ENGINE=what mode you're
in and what server you're connected to.  You can change to other modes with
keystrokes; press 'T' to switch to a list of InnoDB transactions, for example.

Press the '?' key to see what keys are active in the current mode.  You can
press any of these keys and innotop will either take the requested action or
prompt you for more input.  If your system has Term::ReadLine support, you can
use TAB and other keys to auto-complete and edit input.

To quit innotop, press the 'q' key.

=head1 OPTIONS

innotop is mostly configured via its configuration file, but some of the
configuration options can come from the command line.  You can also specify a
file to monitor for InnoDB status output; see L<"MONITORING A FILE"> for more
details.

You can negate some options by prefixing the option name with --no.  For
example, --noinc (or --no-inc) negates L<"--inc">.

=over

=item --color

Enable or disable terminal coloring.  Corresponds to the L<"color"> config file
setting.

=item --config

Specifies a configuration file to read.  This option is non-sticky, that is to
say it does not persist to the configuration file itself.

=item --count

Refresh only the specified number of times (ticks) before exiting.  Each refresh
is a pause for L<"interval"> seconds, followed by requesting data from MySQL
connections and printing it to the terminal.

=item --delay

Specifies the amount of time to pause between ticks (refreshes).  Corresponds to
the configuration option L<"interval">.

=item --help

Print a summary of command-line usage and exit.

=item --host

Host to connect to.

=item --inc

Specifies whether innotop should display absolute numbers or relative numbers
(offsets from their previous values).  Corresponds to the configuration option
L<"status_inc">.

=item --mode

Specifies the mode in which innotop should start.  Corresponds to the
configuration option L<"mode">.

=item --nonint

Enable non-interactive operation.  See L<"NON-INTERACTIVE OPERATION"> for more.

=item --password

Password to use for connection.

=item --port

Port to use for connection.

=item --skipcentral

Don't read the central configuration file.

=item --user

User to use for connection.

=item --version

Output version information and exit.

=item --write

Sets the configuration option L<"readonly"> to 0, making innotop write the
running configuration to ~/.innotop/innotop.conf on exit, if no configuration
file was loaded at start-up.

=back

=head1 HOTKEYS

innotop is interactive, and you control it with key-presses.

=over

=item *

Uppercase keys switch between modes.

=item *

Lowercase keys initiate some action within the current mode.

=item *

Other keys do something special like change configuration or show the
innotop license.

=back

Press '?' at any time to see the currently active keys and what they do.

=head1 MODES

Each of innotop's modes retrieves and displays a particular type of data from
the servers you're monitoring.  You switch between modes with uppercase keys.
The following is a brief description of each mode, in alphabetical order.  To
switch to the mode, press the key listed in front of its heading in the
following list:

=over

=item B: InnoDB Buffers

This mode displays information about the InnoDB buffer pool, page statistics,
insert buffer, and adaptive hash index.  The data comes from SHOW INNODB STATUS.

This mode contains the L<"buffer_pool">, L<"page_statistics">,
L<"insert_buffers">, and L<"adaptive_hash_index"> tables by default.

=item C: Command Summary

This mode is similar to mytop's Command Summary mode.  It shows the
L<"cmd_summary"> table, which looks something like the following:

 Command Summary (? for help) localhost, 25+07:16:43, 2.45 QPS, 3 thd, 5.0.40
 _____________________ Command Summary _____________________
 Name                    Value    Pct     Last Incr  Pct    
 Select_scan             3244858  69.89%          2  100.00%
 Select_range            1354177  29.17%          0    0.00%
 Select_full_join          39479   0.85%          0    0.00%
 Select_full_range_join     4097   0.09%          0    0.00%
 Select_range_check            0   0.00%          0    0.00%

The command summary table is built by extracting variables from
L<"STATUS_VARIABLES">.  The variables must be numeric and must match the prefix
given by the L<"cmd_filter"> configuration variable.  The variables are then
sorted by value descending and compared to the last variable, as shown above.
The percentage columns are percentage of the total of all variables in the
table, so you can see the relative weight of the variables.

The example shows what you see if the prefix is "Select_".  The default
prefix is "Com_".  You can choose a prefix with the 's' key.

It's rather like running SHOW VARIABLES LIKE "prefix%" with memory and
nice formatting.

Values are aggregated across all servers.  The Pct columns are not correctly
aggregated across multiple servers.  This is a known limitation of the grouping
algorithm that may be fixed in the future.

=item D: InnoDB Deadlocks

This mode shows the transactions involved in the last InnoDB deadlock.  A second
table shows the locks each transaction held and waited for.  A deadlock is
caused by a cycle in the waits-for graph, so there should be two locks held and
one waited for unless the deadlock information is truncated.

InnoDB puts deadlock information before some other information in the SHOW
INNODB STATUS output.  If there are a lot of locks, the deadlock information can
grow very large, and there is a limit on the size of the SHOW INNODB
STATUS output.  A large deadlock can fill the entire output, or even be
truncated, and prevent you from seeing other information at all.  If you are
running innotop in another mode, for example T mode, and suddenly you don't see
anything, you might want to check and see if a deadlock has wiped out the data
you need.

If it has, you can create a small deadlock to replace the large one.  Use the
'w' key to 'wipe' the large deadlock with a small one.  This will not work
unless you have defined a deadlock table for the connection (see L<"SERVER
CONNECTIONS">).

You can also configure innotop to automatically detect when a large deadlock
needs to be replaced with a small one (see L<"auto_wipe_dl">).

This mode displays the L<"deadlock_transactions"> and L<"deadlock_locks"> tables
by default.

=item F: InnoDB Foreign Key Errors

This mode shows the last InnoDB foreign key error information, such as the
table where it happened, when and who and what query caused it, and so on.

InnoDB has a huge variety of foreign key error messages, and many of them are
just hard to parse.  innotop doesn't always do the best job here, but there's
so much code devoted to parsing this messy, unparseable output that innotop is
likely never to be perfect in this regard.  If innotop doesn't show you what
you need to see, just look at the status text directly.

This mode displays the L<"fk_error"> table by default.

=item I: InnoDB I/O Info

This mode shows InnoDB's I/O statistics, including the I/O threads, pending I/O,
file I/O miscellaneous, and log statistics.  It displays the L<"io_threads">,
L<"pending_io">, L<"file_io_misc">, and L<"log_statistics"> tables by default.

=item L: Locks

This mode shows information about current locks.  At the moment only InnoDB
locks are supported, and by default you'll only see locks for which transactions
are waiting.  This information comes from the TRANSACTIONS section of the InnoDB
status text.  If you have a very busy server, you may have frequent lock waits;
it helps to be able to see which tables and indexes are the "hot spot" for
locks.  If your server is running pretty well, this mode should show nothing.

You can configure MySQL and innotop to monitor not only locks for which a
transaction is waiting, but those currently held, too.  You can do this with the
InnoDB Lock Monitor (L<http://dev.mysql.com/doc/en/innodb-monitor.html>).  It's
not documented in the MySQL manual, but creating the lock monitor with the
following statement also affects the output of SHOW INNODB STATUS, which innotop
uses:

  CREATE TABLE innodb_lock_monitor(a int) ENGINE=what mode you're
in and what server you're connected to.  You can change to other modes with
keystrokes; press 'T' to switch to a list of InnoDB transactions, for example.

Press the '?' key to see what keys are active in the current mode.  You can
press any of these keys and innotop will either take the requested action or
prompt you for more input.  If your system has Term::ReadLine support, you can
use TAB and other keys to auto-complete and edit input.

To quit innotop, press the 'q' key.

=head1 OPTIONS

innotop is mostly configured via its configuration file, but some of the
configuration options can come from the command line.  You can also specify a
file to monitor for InnoDB status output; see L<"MONITORING A FILE"> for more
details.

You can negate some options by prefixing the option name with --no.  For
example, --noinc (or --no-inc) negates L<"--inc">.

=over

=item --color

Enable or disable terminal coloring.  Corresponds to the L<"color"> config file
setting.

=item --config

Specifies a configuration file to read.  This option is non-sticky, that is to
say it does not persist to the configuration file itself.

=item --count

Refresh only the specified number of times (ticks) before exiting.  Each refresh
is a pause for L<"interval"> seconds, followed by requesting data from MySQL
connections and printing it to the terminal.

=item --delay

Specifies the amount of time to pause between ticks (refreshes).  Corresponds to
the configuration option L<"interval">.

=item --help

Print a summary of command-line usage and exit.

=item --host

Host to connect to.

=item --inc

Specifies whether innotop should display absolute numbers or relative numbers
(offsets from their previous values).  Corresponds to the configuration option
L<"status_inc">.

=item --mode

Specifies the mode in which innotop should start.  Corresponds to the
configuration option L<"mode">.

=item --nonint

Enable non-interactive operation.  See L<"NON-INTERACTIVE OPERATION"> for more.

=item --password

Password to use for connection.

=item --port

Port to use for connection.

=item --skipcentral

Don't read the central configuration file.

=item --user

User to use for connection.

=item --version

Output version information and exit.

=item --write

Sets the configuration option L<"readonly"> to 0, making innotop write the
running configuration to ~/.innotop/innotop.conf on exit, if no configuration
file was loaded at start-up.

=back

=head1 HOTKEYS

innotop is interactive, and you control it with key-presses.

=over

=item *

Uppercase keys switch between modes.

=item *

Lowercase keys initiate some action within the current mode.

=item *

Other keys do something special like change configuration or show the
innotop license.

=back

Press '?' at any time to see the currently active keys and what they do.

=head1 MODES

Each of innotop's modes retrieves and displays a particular type of data from
the servers you're monitoring.  You switch between modes with uppercase keys.
The following is a brief description of each mode, in alphabetical order.  To
switch to the mode, press the key listed in front of its heading in the
following list:

=over

=item B: InnoDB Buffers

This mode displays information about the InnoDB buffer pool, page statistics,
insert buffer, and adaptive hash index.  The data comes from SHOW INNODB STATUS.

This mode contains the L<"buffer_pool">, L<"page_statistics">,
L<"insert_buffers">, and L<"adaptive_hash_index"> tables by default.

=item C: Command Summary

This mode is similar to mytop's Command Summary mode.  It shows the
L<"cmd_summary"> table, which looks something like the following:

 Command Summary (? for help) localhost, 25+07:16:43, 2.45 QPS, 3 thd, 5.0.40
 _____________________ Command Summary _____________________
 Name                    Value    Pct     Last Incr  Pct    
 Select_scan             3244858  69.89%          2  100.00%
 Select_range            1354177  29.17%          0    0.00%
 Select_full_join          39479   0.85%          0    0.00%
 Select_full_range_join     4097   0.09%          0    0.00%
 Select_range_check            0   0.00%          0    0.00%

The command summary table is built by extracting variables from
L<"STATUS_VARIABLES">.  The variables must be numeric and must match the prefix
given by the L<"cmd_filter"> configuration variable.  The variables are then
sorted by value descending and compared to the last variable, as shown above.
The percentage columns are percentage of the total of all variables in the
table, so you can see the relative weight of the variables.

The example shows what you see if the prefix is "Select_".  The default
prefix is "Com_".  You can choose a prefix with the 's' key.

It's rather like running SHOW VARIABLES LIKE "prefix%" with memory and
nice formatting.

Values are aggregated across all servers.  The Pct columns are not correctly
aggregated across multiple servers.  This is a known limitation of the grouping
algorithm that may be fixed in the future.

=item D: InnoDB Deadlocks

This mode shows the transactions involved in the last InnoDB deadlock.  A second
table shows the locks each transaction held and waited for.  A deadlock is
caused by a cycle in the waits-for graph, so there should be two locks held and
one waited for unless the deadlock information is truncated.

InnoDB puts deadlock information before some other information in the SHOW
INNODB STATUS output.  If there are a lot of locks, the deadlock information can
grow very large, and there is a limit on the size of the SHOW INNODB
STATUS output.  A large deadlock can fill the entire output, or even be
truncated, and prevent you from seeing other information at all.  If you are
running innotop in another mode, for example T mode, and suddenly you don't see
anything, you might want to check and see if a deadlock has wiped out the data
you need.

If it has, you can create a small deadlock to replace the large one.  Use the
'w' key to 'wipe' the large deadlock with a small one.  This will not work
unless you have defined a deadlock table for the connection (see L<"SERVER
CONNECTIONS">).

You can also configure innotop to automatically detect when a large deadlock
needs to be replaced with a small one (see L<"auto_wipe_dl">).

This mode displays the L<"deadlock_transactions"> and L<"deadlock_locks"> tables
by default.

=item F: InnoDB Foreign Key Errors

This mode shows the last InnoDB foreign key error information, such as the
table where it happened, when and who and what query caused it, and so on.

InnoDB has a huge variety of foreign key error messages, and many of them are
just hard to parse.  innotop doesn't always do the best job here, but there's
so much code devoted to parsing this messy, unparseable output that innotop is
likely never to be perfect in this regard.  If innotop doesn't show you what
you need to see, just look at the status text directly.

This mode displays the L<"fk_error"> table by default.

=item I: InnoDB I/O Info

This mode shows InnoDB's I/O statistics, including the I/O threads, pending I/O,
file I/O miscellaneous, and log statistics.  It displays the L<"io_threads">,
L<"pending_io">, L<"file_io_misc">, and L<"log_statistics"> tables by default.

=item L: Locks

This mode shows information about current locks.  At the moment only InnoDB
locks are supported, and by default you'll only see locks for which transactions
are waiting.  This information comes from the TRANSACTIONS section of the InnoDB
status text.  If you have a very busy server, you may have frequent lock waits;
it helps to be able to see which tables and indexes are the "hot spot" for
locks.  If your server is running pretty well, this mode should show nothing.

You can configure MySQL and innotop to monitor not only locks for which a
transaction is waiting, but those currently held, too.  You can do this with the
InnoDB Lock Monitor (L<http://dev.mysql.com/doc/en/innodb-monitor.html>).  It's
not documented in the MySQL manual, but creating the lock monitor with the
following statement also affects the output of SHOW INNODB STATUS, which innotop
uses:

  CREATE TABLE innodb_lock_monitor(a int) ENGINE=what mode you're
in and what server you're connected to.  You can change to other modes with
keystrokes; press 'T' to switch to a list of InnoDB transactions, for example.

Press the '?' key to see what keys are active in the current mode.  You can
press any of these keys and innotop will either take the requested action or
prompt you for more input.  If your system has Term::ReadLine support, you can
use TAB and other keys to auto-complete and edit input.

To quit innotop, press the 'q' key.

=head1 OPTIONS

innotop is mostly configured via its configuration file, but some of the
configuration options can come from the command line.  You can also specify a
file to monitor for InnoDB status output; see L<"MONITORING A FILE"> for more
details.

You can negate some options by prefixing the option n