#!/usr/bin/env perl

# This is mk-heartbeat, a script to measure replication delay.
#
# This program is copyright 2007-2009 Percona Inc.
# and copyright 2006 Proven Scaling LLC and Six Apart Ltd.
# 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.

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

our $VERSION = '1.0.13';
our $DISTRIB = '3519';
our $SVN_REV = sprintf("%d", (q$Revision: 3311 $ =~ m/(\d+)/g, 0));

# ###########################################################################
# MasterSlave package 3186
# ###########################################################################
use strict;
use warnings FATAL => 'all';

package MasterSlave;

use English qw(-no_match_vars);
use List::Util qw(min max);
use Data::Dumper;
$Data::Dumper::Quotekeys = 0;
$Data::Dumper::Indent    = 0;

use constant MKDEBUG => $ENV{MKDEBUG};

sub new {
   bless {}, shift;
}

sub recurse_to_slaves {
   my ( $self, $args, $level ) = @_;
   $level ||= 0;
   my $dp   = $args->{dsn_parser};
   my $dsn  = $args->{dsn};

   my $dbh;
   eval {
      $dbh = $args->{dbh} || $dp->get_dbh(
         $dp->get_cxn_params($dsn), { AutoCommit => 1 });
      MKDEBUG && _d('Connected to', $dp->as_string($dsn));
   };
   if ( $EVAL_ERROR ) {
      print STDERR "Cannot connect to ", $dp->as_string($dsn), "\n"
         or die "Cannot print: $OS_ERROR";
      return;
   }

   my $sql  = 'SELECT @@SERVER_ID';
   MKDEBUG && _d($sql);
   my ($id) = $dbh->selectrow_array($sql);
   MKDEBUG && _d('Working on server ID', $id);
   my $master_thinks_i_am = $dsn->{server_id};
   if ( !defined $id
       || ( defined $master_thinks_i_am && $master_thinks_i_am != $id )
       || $args->{server_ids_seen}->{$id}++
   ) {
      MKDEBUG && _d('Server ID seen, or not what master said');
      if ( $args->{skip_callback} ) {
         $args->{skip_callback}->($dsn, $dbh, $level, $args->{parent});
      }
      return;
   }

   $args->{callback}->($dsn, $dbh, $level, $args->{parent});

   if ( !defined $args->{recurse} || $level < $args->{recurse} ) {

      my @slaves =
         grep { !$_->{master_id} || $_->{master_id} == $id } # Only my slaves.
         $self->find_slave_hosts($dp, $dbh, $dsn, $args->{method});

      foreach my $slave ( @slaves ) {
         MKDEBUG && _d('Recursing from',
            $dp->as_string($dsn), 'to', $dp->as_string($slave));
         $self->recurse_to_slaves(
            { %$args, dsn => $slave, dbh => undef, parent => $dsn }, $level + 1 );
      }
   }
}

sub find_slave_hosts {
   my ( $self, $dsn_parser, $dbh, $dsn, $method ) = @_;
   $method ||= '';
   MKDEBUG && _d('Looking for slaves on', $dsn_parser->as_string($dsn));

   my @slaves;

   if ( (!$method && ($dsn->{P}||3306) == 3306) || $method eq 'processlist' ) {
      @slaves =
         map  {
            my $slave        = $dsn_parser->parse("h=$_", $dsn);
            $slave->{source} = 'processlist';
            $slave;
         }
         grep { $_ }
         map  {
            my ( $host ) = $_->{host} =~ m/^([^:]+):/;
            if ( $host eq 'localhost' ) {
               $host = '127.0.0.1'; # Replication never uses sockets.
            }
            $host;
         } $self->get_connected_slaves($dbh);
   }

   if ( !@slaves ) {
      my $sql = 'SHOW SLAVE HOSTS';
      MKDEBUG && _d($dbh, $sql);
      @slaves = @{$dbh->selectall_arrayref($sql, { Slice => {} })};

      if ( @slaves ) {
         MKDEBUG && _d('Found some SHOW SLAVE HOSTS info');
         @slaves = map {
            my %hash;
            @hash{ map { lc $_ } keys %$_ } = values %$_;
            my $spec = "h=$hash{host},P=$hash{port}"
               . ( $hash{user} ? ",u=$hash{user}" : '')
               . ( $hash{password} ? ",p=$hash{password}" : '');
            my $dsn           = $dsn_parser->parse($spec, $dsn);
            $dsn->{server_id} = $hash{server_id};
            $dsn->{master_id} = $hash{master_id};
            $dsn->{source}    = 'hosts';
            $dsn;
         } @slaves;
      }
   }

   MKDEBUG && _d('Found', scalar(@slaves), 'slaves');
   return @slaves;
}

sub get_connected_slaves {
   my ( $self, $dbh ) = @_;

   my $proc =
      grep { m/ALL PRIVILEGES.*?\*\.\*|PROCESS/ }
      @{$dbh->selectcol_arrayref('SHOW GRANTS')};
   if ( !$proc ) {
      die "You do not have the PROCESS privilege";
   }

   my $sql = 'SHOW PROCESSLIST';
   MKDEBUG && _d($dbh, $sql);
   grep { $_->{command} =~ m/Binlog Dump/i }
   map  { # Lowercase the column names
      my %hash;
      @hash{ map { lc $_ } keys %$_ } = values %$_;
      \%hash;
   }
   @{$dbh->selectall_arrayref($sql, { Slice => {} })};
}

sub is_master_of {
   my ( $self, $master, $slave ) = @_;
   my $master_status = $self->get_master_status($master)
      or die "The server specified as a master is not a master";
   my $slave_status  = $self->get_slave_status($slave)
      or die "The server specified as a slave is not a slave";
   my @connected     = $self->get_connected_slaves($master)
      or die "The server specified as a master has no connected slaves";
   my (undef, $port) = $master->selectrow_array('SHOW VARIABLES LIKE "port"');

   if ( $port != $slave_status->{master_port} ) {
      die "The slave is connected to $slave_status->{master_port} "
         . "but the master's port is $port";
   }

   if ( !grep { $slave_status->{master_user} eq $_->{user} } @connected ) {
      die "I don't see any slave I/O thread connected with user "
         . $slave_status->{master_user};
   }

   if ( ($slave_status->{slave_io_state} || '')
      eq 'Waiting for master to send event' )
   {
      my ( $master_log_name, $master_log_num )
         = $master_status->{file} =~ m/^(.*?)\.0*([1-9][0-9]*)$/;
      my ( $slave_log_name, $slave_log_num )
         = $slave_status->{master_log_file} =~ m/^(.*?)\.0*([1-9][0-9]*)$/;
      if ( $master_log_name ne $slave_log_name
         || abs($master_log_num - $slave_log_num) > 1 )
      {
         die "The slave thinks it is reading from "
            . "$slave_status->{master_log_file},  but the "
            . "master is writing to $master_status->{file}";
      }
   }
   return 1;
}

sub get_master_dsn {
   my ( $self, $dbh, $dsn, $dsn_parser ) = @_;
   my $master = $self->get_slave_status($dbh) or return undef;
   my $spec   = "h=$master->{master_host},P=$master->{master_port}";
   return       $dsn_parser->parse($spec, $dsn);
}

sub get_slave_status {
   my ( $self, $dbh ) = @_;
   if ( !$self->{not_a_slave}->{$dbh} ) {
      my $sth = $self->{sths}->{$dbh}->{SLAVE_STATUS}
            ||= $dbh->prepare('SHOW SLAVE STATUS');
      MKDEBUG && _d($dbh, 'SHOW SLAVE STATUS');
      $sth->execute();
      my ($ss) = @{$sth->fetchall_arrayref({})};

      if ( $ss && %$ss ) {
         $ss = { map { lc($_) => $ss->{$_} } keys %$ss }; # lowercase the keys
         return $ss;
      }

      MKDEBUG && _d('This server returns nothing for SHOW SLAVE STATUS');
      $self->{not_a_slave}->{$dbh}++;
   }
}

sub get_master_status {
   my ( $self, $dbh ) = @_;
   if ( !$self->{not_a_master}->{$dbh} ) {
      my $sth = $self->{sths}->{$dbh}->{MASTER_STATUS}
            ||= $dbh->prepare('SHOW MASTER STATUS');
      MKDEBUG && _d($dbh, 'SHOW MASTER STATUS');
      $sth->execute();
      my ($ms) = @{$sth->fetchall_arrayref({})};

      if ( $ms && %$ms ) {
         $ms = { map { lc($_) => $ms->{$_} } keys %$ms }; # lowercase the keys
         if ( $ms->{file} && $ms->{position} ) {
            return $ms;
         }
      }

      MKDEBUG && _d('This server returns nothing for SHOW MASTER STATUS');
      $self->{not_a_master}->{$dbh}++;
   }
}

sub wait_for_master {
   my ( $self, $master, $slave, $time, $timeoutok, $ms ) = @_;
   my $result;
   MKDEBUG && _d('Waiting for slave to catch up to master');
   $ms ||= $self->get_master_status($master);
   if ( $ms ) {
      my $query = "SELECT MASTER_POS_WAIT('$ms->{file}', $ms->{position}, $time)";
      MKDEBUG && _d($slave, $query);
      ($result) = $slave->selectrow_array($query);
      my $stat = defined $result ? $result : 'NULL';
      if ( $stat eq 'NULL' || $stat < 0 && !$timeoutok ) {
         die "MASTER_POS_WAIT returned $stat";
      }
      MKDEBUG && _d('Result of waiting:', $stat);
   }
   else {
      MKDEBUG && _d('Not waiting: this server is not a master');
   }
   return $result;
}

sub stop_slave {
   my ( $self, $dbh ) = @_;
   my $sth = $self->{sths}->{$dbh}->{STOP_SLAVE}
         ||= $dbh->prepare('STOP SLAVE');
   MKDEBUG && _d($dbh, $sth->{Statement});
   $sth->execute();
}

sub start_slave {
   my ( $self, $dbh, $pos ) = @_;
   if ( $pos ) {
      my $sql = "START SLAVE UNTIL MASTER_LOG_FILE='$pos->{file}', "
              . "MASTER_LOG_POS=$pos->{position}";
      MKDEBUG && _d($dbh, $sql);
      $dbh->do($sql);
   }
   else {
      my $sth = $self->{sths}->{$dbh}->{START_SLAVE}
            ||= $dbh->prepare('START SLAVE');
      MKDEBUG && _d($dbh, $sth->{Statement});
      $sth->execute();
   }
}

sub catchup_to_master {
   my ( $self, $slave, $master, $time ) = @_;
   $self->stop_slave($master);
   $self->stop_slave($slave);
   my $slave_status  = $self->get_slave_status($slave);
   my $slave_pos     = $self->repl_posn($slave_status);
   my $master_status = $self->get_master_status($master);
   my $master_pos    = $self->repl_posn($master_status);
   MKDEBUG && _d('Master position:', $self->pos_to_string($master_pos),
      'Slave position:', $self->pos_to_string($slave_pos));
   if ( $self->pos_cmp($slave_pos, $master_pos) < 0 ) {
      MKDEBUG && _d('Waiting for slave to catch up to master');
      $self->start_slave($slave, $master_pos);
      eval {
         $self->wait_for_master($master, $slave, $time, 0, $master_status);
      };
      if ( $EVAL_ERROR ) {
         MKDEBUG && _d($EVAL_ERROR);
         if ( $EVAL_ERROR =~ m/MASTER_POS_WAIT returned NULL/ ) {
            $slave_status = $self->get_slave_status($slave);
            if ( !$self->slave_is_running($slave_status) ) {
               $slave_pos = $self->repl_posn($slave_status);
               if ( $self->pos_cmp($slave_pos, $master_pos) != 0 ) {
                  die "$EVAL_ERROR but slave has not caught up to master";
               }
               MKDEBUG && _d('Slave is caught up to master and stopped');
            }
            else {
               die "$EVAL_ERROR but slave was still running";
            }
         }
         else {
            die $EVAL_ERROR;
         }
      }
   }
}

sub catchup_to_same_pos {
   my ( $self, $s1_dbh, $s2_dbh ) = @_;
   $self->stop_slave($s1_dbh);
   $self->stop_slave($s2_dbh);
   my $s1_status = $self->get_slave_status($s1_dbh);
   my $s2_status = $self->get_slave_status($s2_dbh);
   my $s1_pos    = $self->repl_posn($s1_status);
   my $s2_pos    = $self->repl_posn($s2_status);
   if ( $self->pos_cmp($s1_pos, $s2_pos) < 0 ) {
      $self->start_slave($s1_dbh, $s2_pos);
   }
   elsif ( $self->pos_cmp($s2_pos, $s1_pos) < 0 ) {
      $self->start_slave($s2_dbh, $s1_pos);
   }

   $s1_status = $self->get_slave_status($s1_dbh);
   $s2_status = $self->get_slave_status($s2_dbh);
   $s1_pos    = $self->repl_posn($s1_status);
   $s2_pos    = $self->repl_posn($s2_status);

   if ( $self->slave_is_running($s1_status)
     || $self->slave_is_running($s2_status)
     || $self->pos_cmp($s1_pos, $s2_pos) != 0)
   {
      die "The servers aren't both stopped at the same position";
   }

}

sub change_master_to {
   my ( $self, $dbh, $master_dsn, $master_pos ) = @_;
   $self->stop_slave($dbh);
   MKDEBUG && _d(Dumper($master_dsn), Dumper($master_pos));
   my $sql = "CHANGE MASTER TO MASTER_HOST='$master_dsn->{h}', "
      . "MASTER_PORT= $master_dsn->{P}, MASTER_LOG_FILE='$master_pos->{file}', "
      . "MASTER_LOG_POS=$master_pos->{position}";
   MKDEBUG && _d($dbh, $sql);
   $dbh->do($sql);
}

sub make_sibling_of_master {
   my ( $self, $slave_dbh, $slave_dsn, $dsn_parser, $timeout) = @_;

   my $master_dsn  = $self->get_master_dsn($slave_dbh, $slave_dsn, $dsn_parser)
      or die "This server is not a slave";
   my $master_dbh  = $dsn_parser->get_dbh(
      $dsn_parser->get_cxn_params($master_dsn), { AutoCommit => 1 });
   my $gmaster_dsn
      = $self->get_master_dsn($master_dbh, $master_dsn, $dsn_parser)
      or die "This server's master is not a slave";
   my $gmaster_dbh = $dsn_parser->get_dbh(
      $dsn_parser->get_cxn_params($gmaster_dsn), { AutoCommit => 1 });
   if ( $self->short_host($slave_dsn) eq $self->short_host($gmaster_dsn) ) {
      die "The slave's master's master is the slave: master-master replication";
   }

   $self->stop_slave($master_dbh);
   $self->catchup_to_master($slave_dbh, $master_dbh, $timeout);
   $self->stop_slave($slave_dbh);

   my $master_status = $self->get_master_status($master_dbh);
   my $mslave_status = $self->get_slave_status($master_dbh);
   my $slave_status  = $self->get_slave_status($slave_dbh);
   my $master_pos    = $self->repl_posn($master_status);
   my $slave_pos     = $self->repl_posn($slave_status);

   if ( !$self->slave_is_running($mslave_status)
     && !$self->slave_is_running($slave_status)
     && $self->pos_cmp($master_pos, $slave_pos) == 0)
   {
      $self->change_master_to($slave_dbh, $gmaster_dsn,
         $self->repl_posn($mslave_status)); # Note it's not $master_pos!
   }
   else {
      die "The servers aren't both stopped at the same position";
   }

   $mslave_status = $self->get_slave_status($master_dbh);
   $slave_status  = $self->get_slave_status($slave_dbh);
   my $mslave_pos = $self->repl_posn($mslave_status);
   $slave_pos     = $self->repl_posn($slave_status);
   if ( $self->short_host($mslave_status) ne $self->short_host($slave_status)
     || $self->pos_cmp($mslave_pos, $slave_pos) != 0)
   {
      die "The servers don't have the same master/position after the change";
   }
}

sub make_slave_of_sibling {
   my ( $self, $slave_dbh, $slave_dsn, $sib_dbh, $sib_dsn,
        $dsn_parser, $timeout) = @_;

   if ( $self->short_host($slave_dsn) eq $self->short_host($sib_dsn) ) {
      die "You are trying to make the slave a slave of itself";
   }

   my $master_dsn1 = $self->get_master_dsn($slave_dbh, $slave_dsn, $dsn_parser)
      or die "This server is not a slave";
   my $master_dbh1 = $dsn_parser->get_dbh(
      $dsn_parser->get_cxn_params($master_dsn1), { AutoCommit => 1 });
   my $master_dsn2 = $self->get_master_dsn($slave_dbh, $slave_dsn, $dsn_parser)
      or die "The sibling is not a slave";
   if ( $self->short_host($master_dsn1) ne $self->short_host($master_dsn2) ) {
      die "This server isn't a sibling of the slave";
   }
   my $sib_master_stat = $self->get_master_status($sib_dbh)
      or die "Binary logging is not enabled on the sibling";
   die "The log_slave_updates option is not enabled on the sibling"
      unless $self->has_slave_updates($sib_dbh);

   $self->catchup_to_same_pos($slave_dbh, $sib_dbh);

   $sib_master_stat = $self->get_master_status($sib_dbh);
   $self->change_master_to($slave_dbh, $sib_dsn,
         $self->repl_posn($sib_master_stat));

   my $slave_status = $self->get_slave_status($slave_dbh);
   my $slave_pos    = $self->repl_posn($slave_status);
   $sib_master_stat = $self->get_master_status($sib_dbh);
   if ( $self->short_host($slave_status) ne $self->short_host($sib_dsn)
     || $self->pos_cmp($self->repl_posn($sib_master_stat), $slave_pos) != 0)
   {
      die "After changing the slave's master, it isn't a slave of the sibling, "
         . "or it has a different replication position than the sibling";
   }
}

sub make_slave_of_uncle {
   my ( $self, $slave_dbh, $slave_dsn, $unc_dbh, $unc_dsn,
        $dsn_parser, $timeout) = @_;

   if ( $self->short_host($slave_dsn) eq $self->short_host($unc_dsn) ) {
      die "You are trying to make the slave a slave of itself";
   }

   my $master_dsn = $self->get_master_dsn($slave_dbh, $slave_dsn, $dsn_parser)
      or die "This server is not a slave";
   my $master_dbh = $dsn_parser->get_dbh(
      $dsn_parser->get_cxn_params($master_dsn), { AutoCommit => 1 });
   my $gmaster_dsn
      = $self->get_master_dsn($master_dbh, $master_dsn, $dsn_parser)
      or die "The master is not a slave";
   my $unc_master_dsn
      = $self->get_master_dsn($unc_dbh, $unc_dsn, $dsn_parser)
      or die "The uncle is not a slave";
   if ($self->short_host($gmaster_dsn) ne $self->short_host($unc_master_dsn)) {
      die "The uncle isn't really the slave's uncle";
   }

   my $unc_master_stat = $self->get_master_status($unc_dbh)
      or die "Binary logging is not enabled on the uncle";
   die "The log_slave_updates option is not enabled on the uncle"
      unless $self->has_slave_updates($unc_dbh);

   $self->catchup_to_same_pos($master_dbh, $unc_dbh);
   $self->catchup_to_master($slave_dbh, $master_dbh, $timeout);

   my $slave_status  = $self->get_slave_status($slave_dbh);
   my $master_status = $self->get_master_status($master_dbh);
   if ( $self->pos_cmp(
         $self->repl_posn($slave_status),
         $self->repl_posn($master_status)) != 0 )
   {
      die "The slave is not caught up to its master";
   }

   $unc_master_stat = $self->get_master_status($unc_dbh);
   $self->change_master_to($slave_dbh, $unc_dsn,
      $self->repl_posn($unc_master_stat));


   $slave_status    = $self->get_slave_status($slave_dbh);
   my $slave_pos    = $self->repl_posn($slave_status);
   if ( $self->short_host($slave_status) ne $self->short_host($unc_dsn)
     || $self->pos_cmp($self->repl_posn($unc_master_stat), $slave_pos) != 0)
   {
      die "After changing the slave's master, it isn't a slave of the uncle, "
         . "or it has a different replication position than the uncle";
   }
}

sub detach_slave {
   my ( $self, $dbh ) = @_;
   $self->stop_slave($dbh);
   my $stat = $self->get_slave_status($dbh)
      or die "This server is not a slave";
   $dbh->do('CHANGE MASTER TO MASTER_HOST=""');
   $dbh->do('RESET SLAVE'); # Wipes out master.info, etc etc
   return $stat;
}

sub slave_is_running {
   my ( $self, $slave_status ) = @_;
   return ($slave_status->{slave_sql_running} || 'No') eq 'Yes';
}

sub has_slave_updates {
   my ( $self, $dbh ) = @_;
   my $sql = q{SHOW VARIABLES LIKE 'log_slave_updates'};
   MKDEBUG && _d($dbh, $sql);
   my ($name, $value) = $dbh->selectrow_array($sql);
   return $value && $value =~ m/^(1|ON)$/;
}

sub repl_posn {
   my ( $self, $status ) = @_;
   if ( exists $status->{file} && exists $status->{position} ) {
      return {
         file     => $status->{file},
         position => $status->{position},
      };
   }
   else {
      return {
         file     => $status->{relay_master_log_file},
         position => $status->{exec_master_log_pos},
      };
   }
}

sub get_slave_lag {
   my ( $self, $dbh ) = @_;
   my $stat = $self->get_slave_status($dbh);
   return $stat->{seconds_behind_master};
}

sub pos_cmp {
   my ( $self, $a, $b ) = @_;
   return $self->pos_to_string($a) cmp $self->pos_to_string($b);
}

sub short_host {
   my ( $self, $dsn ) = @_;
   my ($host, $port);
   if ( $dsn->{master_host} ) {
      $host = $dsn->{master_host};
      $port = $dsn->{master_port};
   }
   else {
      $host = $dsn->{h};
      $port = $dsn->{P};
   }
   return ($host || '[default]') . ( ($port || 3306) == 3306 ? '' : ":$port" );
}

sub pos_to_string {
   my ( $self, $pos ) = @_;
   my $fmt  = '%s/%020d';
   return sprintf($fmt, @{$pos}{qw(file position)});
}

sub _d {
   my ($package, undef, $line) = caller 0;
   @_ = map { (my $temp = $_) =~ s/\n/\n# /g; $temp; }
        map { defined $_ ? $_ : 'undef' }
        @_;
   print STDERR "# $package:$line $PID ", join(' ', @_), "\n";
}

1;

# ###########################################################################
# End MasterSlave package
# ###########################################################################

# ###########################################################################
# OptionParser package 3297
# ###########################################################################
package OptionParser;

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

use Getopt::Long;
use List::Util qw(max);
use English qw(-no_match_vars);

use constant MKDEBUG => $ENV{MKDEBUG};

my $POD_link_re = '[LC]<"?([^">]+)"?>';

sub pod_to_spec {
   my ( $self, $file ) = @_;
   $file ||= __FILE__;
   open my $fh, '<', $file or die "Can't open $file: $OS_ERROR";

   my %types = (
      string => 's', # standard Getopt type
      'int'  => 'i', # standard Getopt type
      float  => 'f', # standard Getopt type
      Hash   => 'H', # hash, formed from a comma-separated list
      hash   => 'h', # hash as above, but only if a value is given
      Array  => 'A', # array, similar to Hash
      array  => 'a', # array, similar to hash
      DSN    => 'd', # DSN, as provided by a DSNParser which is in $self->{dsn}
      size   => 'z', # size with kMG suffix (powers of 2^10)
      'time' => 'm', # time, with an optional suffix of s/h/m/d
   );
   my @specs = ();
   my @rules = ();
   my $para;
   my $option;

   local $INPUT_RECORD_SEPARATOR = '';
   while ( $para = <$fh> ) {
      next unless $para =~ m/^=head1 OPTIONS/;
      last;
   }

   while ( $para = <$fh> ) {
      last if $para =~ m/^=over/;
      chomp $para;
      $para =~ s/\s+/ /g;
      $para =~ s/$POD_link_re/$1/go;
      MKDEBUG && _d('First option rules:', $para);
      push @rules, $para;
   }

   do {
      if ( ($option) = $para =~ m/^=item --(.*)/ ) {
         MKDEBUG && _d($para);
         my %props;
         $para = <$fh>;
         if ( $para =~ m/: / ) {
            $para =~ s/\s+\Z//g;
            %props = map { split(/: /, $_) } split(/; /, $para);
            if ( $props{'short form'} ) {
               $props{'short form'} =~ s/-//;
            }
            $para = <$fh>;
         }
         $para =~ s/\s+\Z//g;
         $para =~ s/\s+/ /g;
         $para =~ s/$POD_link_re/$1/go;
         if ( $para =~ m/^[^.]+\.$/ ) {
            $para =~ s/\.$//;
         }

         if ( my ($base_option) =  $option =~ m/^\[no\](.*)/ ) {
            $option = $base_option;
            $props{'negatable'} = 1;
         }

         push @specs, {
            s => $option
               . ( $props{'short form'} ? '|' . $props{'short form'} : '' )
               . ( $props{'negatable'}  ? '!'                        : '' )
               . ( $props{'cumulative'} ? '+'                        : '' )
               . ( $props{type}         ? '=' . $types{$props{type}} : '' ),
            d => $para
               . (defined $props{default} ? " (default $props{default})" : ''),
         };
      }
      while ( $para = <$fh> ) {
         last unless $para;

         if ( $option ) {
            if ( my ($line)
                  = $para =~ m/(allowed with --$option[:]?.*?)\./ ) {
               1 while ( $line =~ s/$POD_link_re/$1/go );
               push @rules, $line;
            }
         }

         if ( $para =~ m/^=head1/ ) {
            $para = undef; # Can't 'last' out of a do {} block.
            last;
         }
         last if $para =~ m/^=item --/;
      }
   } while ( $para );

   close $fh;
   return @specs, @rules;
}

sub new {
   my ( $class, @opts ) = @_;
   my %key_seen;
   my %long_seen;
   my %key_for;
   my %defaults;
   my @mutex;
   my @atleast1;
   my %long_for;
   my %disables;
   my %copyfrom;
   my @allowed_with;

   unshift @opts,
      { s => 'help',    d => 'Show this help message' },
      { s => 'version', d => 'Output version information and exit' };

   foreach my $opt ( @opts ) {
      if ( ref $opt ) { # It's an option spec, not a rule.
         my ( $long, $short ) = $opt->{s} =~ m/^([\w-]+)(?:\|([^!+=]*))?/;
         $opt->{k} = $short || $long;
         $key_for{$long} = $opt->{k};
         $long_for{$opt->{k}} = $long;
         $long_for{$long} = $long;
         $opt->{l} = $long;
         die "Duplicate option $opt->{k}" if $key_seen{$opt->{k}}++;
         die "Duplicate long option $opt->{l}" if $long_seen{$opt->{l}}++;
         $opt->{t} = $short;
         $opt->{n} = $opt->{s} =~ m/!/;
         $opt->{c} = $opt->{s} =~ m/\+/;
         $opt->{g} ||= 'o';
         if ( (my ($y) = $opt->{s} =~ m/=([mdHhAaz])/) ) {
            MKDEBUG && _d('Option', $opt->{k}, 'type:', $y);
            $opt->{y} = $y;
            $opt->{s} =~ s/=./=s/;
         }
         if ( $opt->{d} =~ m/required/ ) {
            $opt->{r} = 1;
            MKDEBUG && _d('Option', $opt->{k}, 'is required');
         }
         if ( (my ($def) = $opt->{d} =~ m/default\b(?: ([^)]+))?/) ) {
            $defaults{$opt->{k}} = defined $def ? $def : 1;
            MKDEBUG && _d('Option', $opt->{k}, 'has a default');
         }
         if ( (my ($dis) = $opt->{d} =~ m/(disables .*)/) ) {
            $disables{$opt->{k}} = [ $class->get_participants($dis) ];
            MKDEBUG && _d('Option', $opt->{k}, $dis);
         }
      }
      else { # It's an option rule, not a spec.
         if ( $opt =~ m/at least one|mutually exclusive|one and only one/ ) {
            my @participants = map {
                  die "No such option '$_' in $opt" unless $long_for{$_};
                  $long_for{$_};
               } $class->get_participants($opt);
            if ( $opt =~ m/mutually exclusive|one and only one/ ) {
               push @mutex, \@participants;
               MKDEBUG && _d(@participants, 'are mutually exclusive');
            }
            if ( $opt =~ m/at least one|one and only one/ ) {
               push @atleast1, \@participants;
               MKDEBUG && _d(@participants, 'require at least one');
            }
         }
         elsif ( $opt =~ m/default to/ ) {
            my @participants = map {
                  die "No such option '$_' in $opt" unless $long_for{$_};
                  $key_for{$_};
               } $class->get_participants($opt);
            $copyfrom{$participants[0]} = $participants[1];
            MKDEBUG && _d(@participants, 'copy from each other');
         }
         elsif ( $opt  =~ m/allowed with/ ) {
            my @participants = map {
                  die "No such option '$_' while processing $opt"
                     unless $long_for{$_};
                  $key_for{$_};
               } $class->get_participants($opt);
            push @allowed_with, \@participants;
         }
      }
   }

   foreach my $dis ( keys %disables ) {
      $disables{$dis} = [
            map {
               if ( !defined $long_for{$_} ) {
                  die "No such option '$_' while processing $dis";
               }
               $long_for{$_};
            } @{$disables{$dis}}
      ];
   }

   my $self = {
      specs        => [ grep { ref $_ } @opts ],
      errors       => [],
      instr        => [ grep { !ref $_ } @opts ],
      mutex        => \@mutex,
      defaults     => \%defaults,
      long_for     => \%long_for,
      atleast1     => \@atleast1,
      disables     => \%disables,
      key_for      => \%key_for,
      copyfrom     => \%copyfrom,
      strict       => 1,
      groups       => [ { k => 'o', d => 'Options' } ],
      allowed_with => \@allowed_with,
      given        => {},
   };

   return bless $self, $class;
}

sub get_participants {
   my ( $self, $str ) = @_;
   my @participants;
   foreach my $thing ( $str =~ m/(--?[\w-]+)/g ) {
      if ( (my ($long) = $thing =~ m/--(.+)/) ) {
         push @participants, $long;
      }
      else {
         foreach my $short ( $thing =~ m/([^-])/g ) {
            push @participants, $short;
         }
      }
   }
   MKDEBUG && _d('Participants for', $str, ':', @participants);
   return @participants;
}

sub parse {
   my ( $self, %defaults ) = @_;
   my @specs = @{$self->{specs}};
   my %factor_for = (k => 1_024, M => 1_048_576, G => 1_073_741_824);
   my %opt_seen;
   my %vals = %{$self->{defaults}};
   @vals{keys %defaults} = values %defaults;
   foreach my $spec ( @specs ) {
      $vals{$spec->{k}} = undef unless defined $vals{$spec->{k}};
      $opt_seen{$spec->{k}} = 1;
   }

   foreach my $key ( keys %defaults ) {
      die "Cannot set default for non-existent option '$key'\n"
         unless $opt_seen{$key};
   }

   $self->{given} = {}; # in case options are re-parsed

   Getopt::Long::Configure('no_ignore_case', 'bundling');
   GetOptions(
      map {
         my $spec = $_;
         $spec->{s} => sub {
                          my ( $opt, $val ) = @_;
                          if ( $spec->{c} ) {
                             $vals{$spec->{k}}++
                          }
                          else {
                             $vals{$spec->{k}} = $val;
                          }
                          MKDEBUG && _d('Given option:',
                             $opt, '(',$spec->{k},') =', $val);
                          $self->{given}->{$spec->{k}} = $vals{$spec->{k}};
                       }
      } @specs
   ) or $self->error('Error parsing options');

   if ( $vals{version} ) {
      my $prog = $self->prog;
      printf("%s  Ver %s Distrib %s Changeset %s\n",
         $prog, $main::VERSION, $main::DISTRIB, $main::SVN_REV)
         or die "Cannot print: $OS_ERROR";
      exit(0);
   }

   if ( @ARGV && $self->{strict} ) {
      $self->error("Unrecognized command-line options @ARGV");
   }

   foreach my $dis ( grep { defined $vals{$_} } keys %{$self->{disables}} ) {
      my @disses = map { $self->{key_for}->{$_} } @{$self->{disables}->{$dis}};
      MKDEBUG && _d('Unsetting options:', @disses);
      @vals{@disses} = map { undef } @disses;
   }

   foreach my $spec ( grep { $_->{r} } @specs ) {
      if ( !defined $vals{$spec->{k}} ) {
         $self->error("Required option --$spec->{l} must be specified");
      }
   }

   foreach my $mutex ( @{$self->{mutex}} ) {
      my @set = grep { defined $vals{$self->{key_for}->{$_}} } @$mutex;
      if ( @set > 1 ) {
         my $note = join(', ',
            map { "--$self->{long_for}->{$_}" }
                @{$mutex}[ 0 .. scalar(@$mutex) - 2] );
         $note .= " and --$self->{long_for}->{$mutex->[-1]}"
               . " are mutually exclusive.";
         $self->error($note);
      }
   }

   foreach my $required ( @{$self->{atleast1}} ) {
      my @set = grep { defined $vals{$self->{key_for}->{$_}} } @$required;
      if ( !@set ) {
         my $note = join(', ',
            map { "--$self->{long_for}->{$_}" }
                @{$required}[ 0 .. scalar(@$required) - 2] );
         $note .= " or --$self->{long_for}->{$required->[-1]}";
         $self->error("Specify at least one of $note");
      }
   }

   foreach my $spec ( grep { $_->{y} && defined $vals{$_->{k}} } @specs ) {
      my $val = $vals{$spec->{k}};
      if ( $spec->{y} eq 'm' ) {
         my ( $num, $suffix ) = $val =~ m/(\d+)([a-z])?$/;
         if ( !$suffix ) {
            my ( $s ) = $spec->{d} =~ m/\(suffix (.)\)/;
            $suffix = $s || 's';
            MKDEBUG && _d('No suffix given; using', $suffix, 'for',
               $spec->{k}, '(value:', $val, ')');
         }
         if ( $suffix =~ m/[smhd]/ ) {
            $val = $suffix eq 's' ? $num            # Seconds
                 : $suffix eq 'm' ? $num * 60       # Minutes
                 : $suffix eq 'h' ? $num * 3600     # Hours
                 :                  $num * 86400;   # Days
            $vals{$spec->{k}} = $val;
            MKDEBUG && _d('Setting option', $spec->{k}, 'to', $val);
         }
         else {
            $self->error("Invalid --$spec->{l} argument");
         }
      }
      elsif ( $spec->{y} eq 'd' ) {
         MKDEBUG && _d('Parsing option', $spec->{y}, 'as a DSN');
         my $from_key = $self->{copyfrom}->{$spec->{k}};
         my $default = {};
         if ( $from_key ) {
            MKDEBUG && _d('Option', $spec->{y}, 'DSN copies from option',
               $from_key);
            $default = $self->{dsn}->parse($self->{dsn}->as_string($vals{$from_key}));
         }
         $vals{$spec->{k}} = $self->{dsn}->parse($val, $default);
      }
      elsif ( $spec->{y} eq 'z' ) {
         my ($pre, $num, $factor) = $val =~ m/^([+-])?(\d+)([kMG])?$/;
         if ( defined $num ) {
            if ( $factor ) {
               $num *= $factor_for{$factor};
               MKDEBUG && _d('Setting option', $spec->{y},
                  'to num', $num, '* factor', $factor);
            }
            $vals{$spec->{k}} = ($pre || '') . $num;
         }
         else {
            $self->error("Invalid --$spec->{l} argument");
         }
      }
   }

   foreach my $spec ( grep { $_->{y} } @specs ) {
      MKDEBUG && _d('Treating option', $spec->{k}, 'as a list');
      my $val = $vals{$spec->{k}};
      if ( $spec->{y} eq 'H' || (defined $val && $spec->{y} eq 'h') ) {
         $vals{$spec->{k}} = { map { $_ => 1 } split(',', ($val || '')) };
      }
      elsif ( $spec->{y} eq 'A' || (defined $val && $spec->{y} eq 'a') ) {
         $vals{$spec->{k}} = [ split(',', ($val || '')) ];
      }
   }

   foreach my $allowed_opts ( @{ $self->{allowed_with} } ) {
      my $opt = $allowed_opts->[0];
      next unless $vals{$opt};
      my %defined_opts = map { $_ => 1 } grep { defined $vals{$_} } keys %vals;
      delete @defined_opts{ @$allowed_opts };
      foreach my $defined_opt ( keys %defined_opts ) {
         MKDEBUG
            && _d('Unsetting option', $defined_opt,
               '; it is not allowed with option', $opt);
         $vals{$defined_opt} = undef;
      }
   }

   return %vals;
}

sub error {
   my ( $self, $note ) = @_;
   $self->{__error__} = 1;
   push @{$self->{errors}}, $note;
}

sub prog {
   (my $prog) = $PROGRAM_NAME =~ m/([.A-Za-z-]+)$/;
   return $prog || $PROGRAM_NAME;
}

sub prompt {
   my ( $self ) = @_;
   my $prog   = $self->prog;
   my $prompt = $self->{prompt} || '<options>';
   return "Usage: $prog $prompt\n";
}

sub descr {
   my ( $self ) = @_;
   my $prog = $self->prog;
   my $descr  = $prog . ' ' . ($self->{descr} || '')
          . "  For more details, please use the --help option, "
          . "or try 'perldoc $prog' for complete documentation.";
   $descr = join("\n", $descr =~ m/(.{0,80})(?:\s+|$)/g);
   $descr =~ s/ +$//mg;
   return $descr;
}

sub usage_or_errors {
   my ( $self, %opts ) = @_;
   if ( $opts{help} ) {
      print $self->usage(%opts)
         or die "Cannot print: $OS_ERROR";
      exit(0);
   }
   elsif ( $self->{__error__} ) {
      print $self->errors()
         or die "Cannot print: $OS_ERROR";
      exit(0);
   }
}

sub errors {
   my ( $self ) = @_;
   my $usage = $self->prompt() . "\n";
   if ( (my @errors = @{$self->{errors}}) ) {
      $usage .= join("\n  * ", 'Errors in command-line arguments:', @errors) . "\n";
   }
   return $usage . "\n" . $self->descr();
}

sub usage {
   my ( $self, %vals ) = @_;
   my @specs = @{$self->{specs}};

   my $maxl = max(map { length($_->{l}) + ($_->{n} ? 4 : 0)} @specs);

   my $maxs = max(0,
      map { length($_->{l}) + ($_->{n} ? 4 : 0)}
      grep { $_->{t} } @specs);

   my $lcol = max($maxl, ($maxs + 3));
   my $rcol = 80 - $lcol - 6;
   my $rpad = ' ' x ( 80 - $rcol );

   $maxs = max($lcol - 3, $maxs);

   my $usage = $self->descr() . "\n" . $self->prompt();
   foreach my $g ( @{$self->{groups}} ) {
      $usage .= "\n$g->{d}:\n";
      foreach my $spec (
         sort { $a->{l} cmp $b->{l} } grep { $_->{g} eq $g->{k} } @specs )
      {
         my $long  = $spec->{n} ? "[no]$spec->{l}" : $spec->{l};
         my $short = $spec->{t};
         my $desc  = $spec->{d};
         if ( $spec->{y} && $spec->{y} eq 'm' ) {
            my ($s) = $desc =~ m/\(suffix (.)\)/;
            $s    ||= 's';
            $desc =~ s/\s+\(suffix .\)//;
            $desc .= ".  Optional suffix s=seconds, m=minutes, h=hours, "
                   . "d=days; if no suffix, $s is used.";
         }
         $desc = join("\n$rpad", grep { $_ } $desc =~ m/(.{0,$rcol})(?:\s+|$)/g);
         $desc =~ s/ +$//mg;
         if ( $short ) {
            $usage .= sprintf("  --%-${maxs}s -%s  %s\n", $long, $short, $desc);
         }
         else {
            $usage .= sprintf("  --%-${lcol}s  %s\n", $long, $desc);
         }
      }
   }

   if ( (my @instr = @{$self->{instr}}) ) {
      $usage .= join("\n", map { "  $_" } @instr) . "\n";
   }
   if ( $self->{dsn} ) {
      $usage .= "\n" . $self->{dsn}->usage();
   }
   $usage .= "\nOptions and values after processing arguments:\n";
   foreach my $spec ( sort { $a->{l} cmp $b->{l} } @specs ) {
      my $val   = $vals{$spec->{k}};
      my $type  = $spec->{y} || '';
      my $bool  = $spec->{s} =~ m/^[\w-]+(?:\|[\w-])?!?$/;
      $val      = $bool                     ? ( $val ? 'TRUE' : 'FALSE' )
                : !defined $val             ? '(No value)'
                : $type eq 'd'              ? $self->{dsn}->as_string($val)
                : $type =~ m/H|h/           ? join(',', sort keys %$val)
                : $type =~ m/A|a/           ? join(',', @$val)
                :                             $val;
      $usage .= sprintf("  --%-${lcol}s  %s\n", $spec->{l}, $val);
   }
   return $usage;
}

sub prompt_noecho {
   shift @_ if ref $_[0] eq __PACKAGE__;
   my ( $prompt ) = @_;
   local $OUTPUT_AUTOFLUSH = 1;
   print $prompt
      or die "Cannot print: $OS_ERROR";
   my $response;
   eval {
      require Term::ReadKey;
      Term::ReadKey::ReadMode('noecho');
      chomp($response = <STDIN>);
      Term::ReadKey::ReadMode('normal');
      print "\n"
         or die "Cannot print: $OS_ERROR";
   };
   if ( $EVAL_ERROR ) {
      die "Cannot read response; is Term::ReadKey installed? $EVAL_ERROR";
   }
   return $response;
}

sub groups {
   my ( $self, @groups ) = @_;
   push @{$self->{groups}}, @groups;
}

if ( MKDEBUG ) {
   print '# ', $^X, ' ', $], "\n";
   my $uname = `uname -a`;
   if ( $uname ) {
      $uname =~ s/\s+/ /g;
      print "# $uname\n";
   }
   printf("# %s  Ver %s Distrib %s Changeset %s line %d\n",
      $PROGRAM_NAME, ($main::VERSION || ''), ($main::DISTRIB || ''),
      ($main::SVN_REV || ''), __LINE__);
   print('# Arguments: ',
      join(' ', map { my $a = "_[$_]_"; $a =~ s/\n/\n# /g; $a; } @ARGV), "\n");
}

sub read_para_after {
   my ( $self, $file, $regex ) = @_;
   open my $fh, "<", $file or die "Can't open $file: $OS_ERROR";
   local $INPUT_RECORD_SEPARATOR = '';
   my $para;
   while ( $para = <$fh> ) {
      next unless $para =~ m/^=pod$/m;
      last;
   }
   while ( $para = <$fh> ) {
      next unless $para =~ m/$regex/;
      last;
   }
   $para = <$fh>;
   chomp($para);
   close $fh or die "Can't close $file: $OS_ERROR";
   return $para;
}

sub _d {
   my ($package, undef, $line) = caller 0;
   @_ = map { (my $temp = $_) =~ s/\n/\n# /g; $temp; }
        map { defined $_ ? $_ : 'undef' }
        @_;
   print STDERR "# $package:$line $PID ", join(' ', @_), "\n";
}

1;

# ###########################################################################
# End OptionParser package
# ###########################################################################

# ###########################################################################
# DSNParser package 3186
# ###########################################################################
use strict;
use warnings FATAL => 'all';

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};

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;
}

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');

   foreach my $dsn_part ( split(/,/, $dsn) ) {
      if ( my ($prop_key, $prop_val) = $dsn_part =~  m/^(.)=(.*)$/ ) {
         $given_props{$prop_key} = $prop_val;
      }
      elsif ( $prop_autokey ) {
         MKDEBUG && _d('Interpreting', $dsn_part, 'as',
            $prop_autokey, '=', $dsn_part);
         $given_props{$prop_autokey} = $dsn_part;
      }
      else {
         MKDEBUG && _d('Bad DSN part:', $dsn_part);
      }
   }

   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');
      }
   }

   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;
}

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});
}

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 && $tries-- ) {
      MKDEBUG && _d($cxn_string, ' ', $user, ' ', $pass, ' {',
         join(', ', map { "$_=>$defaults->{$_}" } keys %$defaults ), '}');

      eval {
         $dbh = DBI->connect($cxn_string, $user, $pass, $defaults);

         if ( $cxn_string =~ m/mysql/i ) {
            my $sql;

            $sql = q{SET @@SQL_QUOTE_SHOW_CREATE = 1}
                 . q{/*!40101, @@SQL_MODE='NO_AUTO_VALUE_ON_ZERO'*/};
            MKDEBUG && _d($dbh, ':', $sql);
            $dbh->do($sql);

            if ( my ($charset) = $cxn_string =~ m/charset=(\w+)/ ) {
               $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 ( $self->prop('setvars') ) {
               $sql = "SET " . $self->prop('setvars');
               MKDEBUG && _d($dbh, ':', $sql);
               $dbh->do($sql);
            }
         }
      };
      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;
         }
      }
   }

   MKDEBUG && _d('DBH info: ',
      $dbh,
      Dumper($dbh->selectrow_hashref(
         'SELECT DATABASE(), CONNECTION_ID(), VERSION()/*!50038 , @@hostname*/')),
      'Connection info:',      $dbh->{mysql_hostinfo},
      'Character set info:',   Dumper($dbh->selectall_arrayref(
                     'SHOW VARIABLES LIKE "character_set%"', { Slice => {}})),
      '$DBD::mysql::VERSION:', $DBD::mysql::VERSION,
      '$DBI::VERSION:',        $DBI::VERSION,
   );

   return $dbh;
}

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;
}

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' }
        @_;
   print STDERR "# $package:$line $PID ", join(' ', @_), "\n";
}

1;

# ###########################################################################
# End DSNParser package
# ###########################################################################

# ###########################################################################
# Daemon package 3186
# ###########################################################################

package Daemon;

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

use POSIX;
use English qw(-no_match_vars);

use constant MKDEBUG => $ENV{MKDEBUG};

sub new {
   my ( $class, %args ) = @_;
   my $self = { %args };
   $self->{reopen_STDIN}  ||= '/dev/null';
   $self->{reopen_STDOUT} ||= '/dev/null';
   $self->{reopen_STDERR} ||= '&STDOUT';

   $self->{PID_file}        = undef;

   return bless $self, $class;
}

sub daemonize {
   my ( $self ) = @_;

   defined( my $pid = fork ) or die "Can't fork: $OS_ERROR";
   exit if $pid;
   POSIX::setsid() or die "Can't start a new session: $OS_ERROR";

   chdir '/' or die "Can't chdir to /: $OS_ERROR";

   open STDIN,  "$self->{reopen_STDIN}",
      or die "Cannot reopen STDIN $self->{reopen_STDIN}: $OS_ERROR";
   open STDOUT, ">$self->{reopen_STDOUT}"
      or die "Cannot reopen STDOUT >$self->{reopen_STDOUT}: $OS_ERROR";
   open STDERR, ">$self->{reopen_STDERR}"
      or die "Cannot reopen STDERR >$self->{reopen_STDERR}: $OS_ERROR";


   return;
}

sub create_PID_file {
   my ( $self, $PID_file ) = @_;
   return if !$PID_file;
   $self->{PID_file} = $PID_file; # save for unlink in DESTORY()
   open my $PID_FILE, "+> $self->{PID_file}"
      or die "Cannot open PID file '$self->{PID_file}': $OS_ERROR";
   print $PID_FILE $PID;
   close $PID_FILE
      or die "Cannot close PID file '$self->{PID_file}': $OS_ERROR";
   return;
}

sub remove_PID_file {
   my ( $self ) = @_;
   if ( defined $self->{PID_file} ) {
      unlink $self->{PID_file}
         or warn "Cannot remove PID file '$self->{PID_file}': $OS_ERROR";
   }
   return;
}

sub DESTROY {
   my ( $self ) = @_;
   $self->remove_PID_file();
   return;
}

sub _d {
   my ($package, undef, $line) = caller 0;
   @_ = map { (my $temp = $_) =~ s/\n/\n# /g; $temp; }
        map { defined $_ ? $_ : 'undef' }
        @_;
   print STDERR "# $package:$line $PID ", join(' ', @_), "\n";
}

1;

# ###########################################################################
# End Daemon package
# ###########################################################################

# ###########################################################################
# And now for the "program".
# ###########################################################################

package main;

use English qw(-no_match_vars);
use List::Util qw(min max sum);
use Time::HiRes qw(usleep gettimeofday);
use IO::File;

use constant MKDEBUG => $ENV{MKDEBUG};

# ############################################################################
# Get configuration information.
# ############################################################################

my @opt_spec = OptionParser::pod_to_spec();
my $opt_parser = OptionParser->new(@opt_spec);
$opt_parser->{prompt} = '<options> {--update|--monitor|--check|--stop}';
$opt_parser->{descr}  = q{measures replication lag on a MySQL or PostgreSQL }
                      . q{server.  You can use it to update a master or }
                      . q{monitor a slave.  If possible, MySQL connection }
                      . q{options are read from your .my.cnf file.};
my %opts = $opt_parser->parse();

if ( MKDEBUG && $opts{daemonize} ) {
      die "Cannot debug while daemonized!";
}

if ( !$opts{help} ) {
   my @frames = $opts{frames} =~ m/(\d+[smhd])/g;
   if ( @frames ) {
      $opts{frames} = [];
      foreach my $frame ( @frames ) {
         my ($num, $suf ) = $frame =~ m/(\d+)([smhd])$/;
         if ( !$num ) {
            $opt_parser->error("Invalid --frames argument");
         }
         else {
            push @{$opts{frames}}, 
                 $suf eq 's' ? $num            # Seconds
               : $suf eq 'm' ? $num * 60       # Minutes
               : $suf eq 'h' ? $num * 3600     # Hours
               :               $num * 86400;   # Days
         }
      }
   }
   else {
      $opt_parser->error("Invalid --frames argument");
   }
}

$opts{i} ||= 1; # Prevent 0-second interval

$opt_parser->usage_or_errors(%opts);

# ############################################################################
# First things first: if --stop was given, create the sentinel file.
# ############################################################################
if ( $opts{stop} ) {
   MKDEBUG && _d("Creating sentinel file", $opts{sentinel});
   my $file = IO::File->new($opts{sentinel}, ">>")
      or die "Cannot open $opts{sentinel}: $OS_ERROR\n";
   print $file "Remove this file to permit mk-heartbeat to run\n"
      or die "Cannot write to $opts{sentinel}: $OS_ERROR\n";
   close $file
      or die "Cannot close $opts{sentinel}: $OS_ERROR\n";
   print STDOUT "Successfully created file $opts{sentinel}\n"
      unless $opts{q};
   # Exit only if no other action (update, monitor, check) is given.
   if ( !$opts{update} && !$opts{check} && !$opts{monitor} ) {
      MKDEBUG && _d("Nothing more to do, quitting");
      exit(0);
   }
   else {
      # Wait for all other running instances to quit, assuming they have the
      # same --interval as this invocation.  Then remove the file and
      # continue.
      MKDEBUG && _d("Waiting for other instances to quit");
      sleep($opts{i});
      MKDEBUG && _d("Unlinking", $opts{sentinel});
      unlink $opts{sentinel}
         or die "Cannot unlink $opts{sentinel}: $OS_ERROR";
   }
}

# ############################################################################
# Work.
# ############################################################################

# Get the password before daemonizing.
if ( !$opts{p} && $opts{askpass} ) {
   $opts{p} = OptionParser::prompt_noecho("Enter password: ");
}

my $update_sql = $opts{r}
               ? "REPLACE INTO $opts{t}(id, ts) VALUES(1, NOW())"
               : "UPDATE $opts{t} SET ts = NOW() WHERE id = 1";
my $select_sql = "SELECT "
               . ( $opts{dbidriver} eq 'Pg'
                  ? "ROUND(DATE_PART('epoch', NOW() - ts)) AS delay"
                  : 'UNIX_TIMESTAMP() - UNIX_TIMESTAMP(ts) AS delay/*!50038, @@hostname AS host*/' )
               . " FROM $opts{t} WHERE id = 1";

MKDEBUG && _d("UPDATE SQL:", $update_sql);
MKDEBUG && _d("SELECT SQL:", $select_sql);

my $dp    = new DSNParser;
$dp->prop('dbidriver', $opts{dbidriver});
$dp->prop('setvars', $opts{setvars});
my $dsn   = $dp->parse('bogus', {}, \%opts);
my $dbh   = $dp->get_dbh($dp->get_cxn_params($dsn), { AutoCommit => 1 });
my $sth   = $dbh->prepare($opts{update} ? $update_sql : $select_sql);

$dbh->{InactiveDestroy}  = 1; # Don't disconnect on fork
my @dbhs;                     # Holds slave DBHs if --recurse
my @sths;                     # Holds [$host, $sth] if --recurse

# Do a little check just to make sure the table is there, so there's one last
# chance to catch errors before daemonizing.
$sth->execute();
$sth->finish();

# Check that heartbeat table has at least 1 row
my $row = $dbh->selectall_arrayref("SELECT id FROM $opts{t} LIMIT 1");
if ( scalar @$row == 0 ) {
   die "The heartbeat table is empty.\n"
      . "At least one row must be inserted into the heartbeat table.\n"
      . "Please read the DESCRIPTION section of the mk-heartbeat POD.\n";
}

# Daemonize only after (potentially) asking for passwords for --askpass.
my $daemon;
if ( $opts{daemonize} ) {
   $daemon = new Daemon() or die "Cannot daemonize: $OS_ERROR";
   $daemon->daemonize();
   if ( defined $opts{pid} ) {
      $daemon->create_PID_file( $opts{pid} );
   } 
   # I'm a daemon now.
}

# Setup for moving averages.
my @samples;
my $limit  = max(@{$opts{frames}});
my $format = "%4ds [ " . join(", ", map { "%5.2fs" } @{$opts{frames}}) . " ]\n";

my $now = time();
my $end = $now + ($opts{m} || 0);    # When to exit
MKDEBUG && _d("Will exit at", $end);

# --monitor and --update run in a loop, but --check only checks once and
# exits.
if ( $opts{check} ) {
   check_delay();
   quit();
}

# Quit if time is exceeded or sentinel exists.
while ( ( !$opts{m} || $now < $end ) && !-f $opts{sentinel} ) {
   eval {

      my @now = gettimeofday();
      usleep(
         (($opts{i} - ($now[0] % $opts{i})) * 1_000_000) - $now[1]
         # --update happens at the second boundary, but --monitor and --check
         # are delayed to avoid spurious results.
         + ($opts{update} ? 0 : $opts{k} ));
      MKDEBUG && _d('Woke up at', gettimeofday());

      # Connect or reconnect if necessary.
      if ( !$dbh->ping ) {
         $dbh = $dp->get_dbh($dp->get_cxn_params($dsn), { AutoCommit => 1 });
         $sth = undef;
      }

      if ( $opts{monitor} ) {

         # Get the data
         $sth ||= $dbh->prepare($select_sql);
         $sth->execute;
         MKDEBUG && _d($sth->{Statement});
         my ( $delay ) = $sth->fetchrow_array;
         MKDEBUG && _d("Found delay of", $delay);
         unshift @samples, $delay;
         pop @samples if @samples > $limit;

         # Calculate and print results

         my @vals = map {
            my $bound = min($_, scalar(@samples));
            sum(@samples[0 .. $bound-1]) / $_;
         } @{$opts{frames}};
         my $output = sprintf($format, $delay, @vals);
         if ( $opts{file} ) {
            open my $file, ">", $opts{file}
               or die "Can't open $opts{file}: $OS_ERROR";
            print $file $output
               or die "Can't print to  $opts{file}: $OS_ERROR";
            close $file or die "Can't close $opts{file}: $OS_ERROR";
         }
         else {
            print $output
               unless $opts{q};
         }

      }

      else { # --update mode
         $sth ||= $dbh->prepare($update_sql);
         $sth->execute;
         MKDEBUG && _d($sth->{Statement});
      }
   };
   if ( $EVAL_ERROR ) {
      my ( $err ) = $EVAL_ERROR =~ m/^(?:DBI|DBD).*failed: (.*?)\s*at \S+ line .*/;
      if ( $err ) {
         print STDERR $err, "\n";
      }
      else {
         die $EVAL_ERROR;
      }
   }
   $now = time();
}

quit();

# ############################################################################
# Subroutines.
# ############################################################################

# Check the delay on a single server.  Optionally recurse to all its slaves.
sub check_delay {

   # Collect a list of connections to the slaves.
   if ( $opts{recurse} ) {
      my $ms = new MasterSlave();
      $ms->recurse_to_slaves(
         {  dbh => $dbh,
            dsn => $dsn,
            dsn_parser => $dp,
            recurse    => $opts{recurse},
            callback   => sub {
               my ( $dsn, $dbh, $level ) = @_;
               push @dbhs, $dbh;
               push @sths, [ $dsn->{h}, $dbh->prepare($select_sql) ];
            },
         },
      );
   }
   else {
      push @sths, [ $dsn->{h}, $sth ];
   }

   # Assume that each query will be very fast, so there's no real need to
   # sleep between EACH server checked.
   my @now = gettimeofday();
   usleep((($opts{i} - ($now[0] % $opts{i})) * 1_000_000) - $now[1] + $opts{k});
   MKDEBUG && _d('Woke up at', gettimeofday());

   foreach my $thing ( @sths ) {
      my ( $host, $sth ) = @$thing;
      $sth->execute();
      my ( $delay, $hostname ) = $sth->fetchrow_array;
      $host ||= $hostname || '';
      MKDEBUG && _d("Found delay of", $delay, "on", $host);

      if ( $opts{recurse} && $host  ) {
         # Must print not only the delay, but the server's hostname if
         # available.
         printf("%-10s %5d\n", $host, $delay) unless $opts{q};
      }
      else {
         # Just print the delay.
         printf("%d\n", $delay) unless $opts{q};
      }
   }
   quit();
}

sub quit {
   $sth->finish() if $sth;
   foreach my $handle ( @sths ) {
      my $sth = $handle->[1];
      $sth->finish() if $sth;
   }
   foreach my $handle ( $dbh, @dbhs ) {
      $handle->disconnect() if $handle;
   }
   exit(0);
}

sub _d {
   my ($package, undef, $line) = caller 0;
   @_ = map { (my $temp = $_) =~ s/\n/\n# /g; $temp; }
        map { defined $_ ? $_ : 'undef' }
        @_;
   print STDERR "# $package:$line $PID ", join(' ', @_), "\n";
}

# ############################################################################
# Documentation.
# ############################################################################

=pod

=head1 NAME

mk-heartbeat - Monitor MySQL replication delay.

=head1 SYNOPSIS

 mk-heartbeat -D test --update -h master-server
 mk-heartbeat -D test --monitor -h slave-server
 mk-heartbeat -D test --monitor -h slave-server --dbidriver Pg

=head1 DESCRIPTION

mk-heartbeat is a two-part MySQL and PostgreSQL replication delay monitoring
system that doesn't require the slave to be working (in other words, it doesn't
rely on C<SHOW SLAVE STATUS> on MySQL).  The first part updates a timestamp
every second on the master.  You must create a table on the master as follows:

 CREATE TABLE heartbeat (
   id int NOT NULL PRIMARY KEY,
   ts datetime NOT NULL
 );
 INSERT INTO heartbeat(id) VALUES(1);

The C<MEMORY> storage engine is suggested, but not required of course, for
MySQL.

Now you connect mk-heartbeat to the master and run it in L<"--update"> mode
to generate the heartbeat.  This completes the first part.

The second part is to monitor the slave's delay with L<"--monitor"> or
L<"--check">.  This works even on daisy-chained slaves to any depth.

mk-heartbeat has a one-second resolution.  It depends on the clocks on the
master and slave servers being closely synchronized via NTP.  L<"--update">
checks happen on the edge of the second, and L<"--monitor"> checks happen
halfway between seconds.  As long as the servers' clocks aren't skewed much
and the replication events are propagating in less than half a second,
mk-heartbeat will report zero seconds of delay.

mk-heartbeat will try to reconnect if the connection has an error, but will
not retry if it can't get a connection when it first starts.

The L<"--dbidriver"> option lets you use mk-heartbeat to monitor PostgreSQL
as well.  It is reported to work well with Slony-1 replication.

=head1 DOWNLOADING

You can download Maatkit from Google Code at
L<http://code.google.com/p/maatkit/>, or you can get any of the tools
easily with a command like the following:

   wget http://www.maatkit.org/get/toolname
   or
   wget http://www.maatkit.org/trunk/toolname

Where C<toolname> can be replaced with the name (or fragment of a name) of any
of the Maatkit tools.  Once downloaded, they're ready to run; no installation is
needed.  The first URL gets the latest released version of the tool, and the
second gets the latest trunk code from Subversion.

=head1 OPTIONS

Specify at least one of --stop, --update, --monitor, or --check.

--update, --monitor, and --check are mutually exclusive.

--daemonize and --check are mutually exclusive.

=over

=item --askpass

Prompt for a password when connecting to MySQL.

=item --charset

short form: -A; type: string

Default character set.

Enables character set settings in Perl and MySQL.  If the value is C<utf8>, sets
Perl's binmode on STDOUT to utf8, passes the C<mysql_enable_utf8> option to
DBD::mysql, and runs C<SET NAMES UTF8> after connecting to MySQL.  Any other
value sets binmode on STDOUT without the utf8 layer, and runs C<SET NAMES> after
connecting to MySQL.

=item --check

Check slave delay once and exit.

=item --daemonize

Fork to the background and detach from the shell.  POSIX only.

=item --database

short form: -D; type: string

The database to use for the connection.

=item --dbidriver

default: mysql; type: string

Specify a driver for the connection; C<mysql> and C<Pg> are supported.

=item --defaults-file

short form: -F; type: string

Only read mysql options from the given file.  You must give an absolute
pathname.

=item --file

type: string

Print latest --monitor output to this file.

When L<"--monitor"> is given, prints output to the specified file instead of to
STDOUT.  The file is opened, truncated, and closed every interval, so it will
only contain the most recent statistics.  Useful when L<"--daemonize"> is given.

=item --frames

type: string; default: 1m,5m,15m

Timeframes for averages.

Specifies the timeframes over which to calculate moving averages when
L<"--monitor"> is given.  Specify as a comma-separated list of numbers with
suffixes.  The suffix can be s for seconds, m for minutes, h for hours, or d for
days.  The size of the largest frame determines the maximum memory usage, as up
to the specified number of per-second samples are kept in memory to calculate
the averages.  You can specify as many timeframes as you like.

=item --host

short form: -h; type: string

Connect to host.

=item --interval

short form: -i; type: time; default: 1s

Interval between updates and checks.

How often to check or update values.  The updates and checks will happen when
the Unix time (seconds since epoch) is an even multiple of this value.  The
suffix is similar to L<"--frames">.

=item --monitor

Monitor slave delay continuously.

Specifies that mk-heartbeat should check the slave's delay every second and
report to STDOUT (or if L<"--file"> is given, to the file instead).  The output
is the current delay followed by moving averages over the timeframe given in
L<"--frames">.  For example,

 5s [  0.25s,  0.05s,  0.02s ]

=item --password

short form: -p; type: string

Password to use when connecting.

=item --pid

type: string 

Create the given PID file when daemonized.

For example, '--daemonize --pid /tmp/mk-heartbeat.pid' would cause
mk-heartbeat to create the PID file /tmp/mk-heartbeat.pid.

/var/run/ is usually not writable by non-root users, therefore /tmp/ is a
more reliable alternative.

The PID file is removed when the daemonized instance of mk-heartbeat exits.

=item --port

short form: -P; type: int

Port number to use for connection.

=item --quiet

short form: -q

Suppresses normal output.

=item --recurse

type: int

Check slaves recursively to this depth in L<"--check"> mode.

Try to discover slave servers recursively, to the specified depth.  After
discovering servers, run the check on each one of them and print the hostname
(if possible), followed by the slave delay.

This currently works only with MySQL.  It uses C<SHOW PROCESSLIST> to discover
slaves; if that returns nothing, it falls back to examining the output of C<SHOW
SLAVE HOSTS> to try to find slaves.

=item --replace

short form: -r

Use C<REPLACE> instead of C<UPDATE> for --update.

When running in L<"--update"> mode, use C<REPLACE> instead of C<UPDATE> to set
the heartbeat table's timestamp.  The C<REPLACE> statement is a MySQL extension
to SQL.  This option is useful when you don't know whether the table contains
any rows or not.

=item --sentinel

type: string; default: /tmp/mk-heartbeat-sentinel

Exit if this file exists.

=item --setvars

type: string; default: wait_timeout=10000

Set these MySQL variables.

Specify any variables you want to be set immediately after connecting to MySQL.
These will be included in a C<SET> command.

=item --skew

short form: -k; type: int; default: 500000

How long to delay checks, in milliseconds.

The default is to delay checks one half second.  Since the update happens as
soon as possible after the beginning of the second on the master, this allows
one half second of replication delay before reporting that the slave lags the
master by one second.  If your clocks are not completely accurate or there is
some other reason you'd like to delay the slave more or less, you can tweak this
value.  Try setting the C<MKDEBUG> environment variable to see the effect this
has.

=item --socket

short form: -S; type: string

Socket file to use for connection.

=item --stop

Stop running instances by creating the sentinel file.

This should have the effect of stopping all running
instances which are watching the same sentinel file.  If none of
L<"--update">, L<"--monitor"> or L<"--check"> is specified, C<mk-heartbeat>
will exit after creating the file.  If one of these is specified,
C<mk-heartbeat> will wait the interval given by L<"--interval">, then remove
the file and continue working.

You might find this handy to stop cron jobs gracefully if necessary, or to
replace one running instance with another.  For example, if you want to stop
and restart C<mk-heartbeat> every hour (just to make sure that it is restarted
every hour, in case of a server crash or some other problem), you could use a
C<crontab> line like this:

 0 * * * * mk-heartbeat --update -D test --stop --sentinel /tmp/mk-heartbeatup

The non-default L<"--sentinel"> will make sure the hourly C<cron> job stops
only instances previously started with the same options (that is, from the
same C<cron> job).

See also L<"--sentinel">.

=item --table

short form: -t; type: string; default: heartbeat

The table to use for the heartbeat.

Don't specify database.table; use L<"--database"> to specify the database.

=item --time

short form: -m; type: time

Time to run before exiting.

=item --update

Update a master's heartbeat.

=item --user

short form: -u; type: string

User for login if not current user.

=back

=head1 ENVIRONMENT

The environment variable C<MKDEBUG> enables verbose debugging output in all of the
Maatkit tools:

   MKDEBUG=1 mk-....

=head1 SYSTEM REQUIREMENTS

You need Perl, DBI, DBD::mysql, and some core packages that ought to be
installed in any reasonably new version of Perl.

=head1 SEE ALSO

See also L<mk-slave-delay> and L<mk-slave-restart>.

=head1 BUGS

Please use Google Code Issues and Groups to report bugs or request support:
L<http://code.google.com/p/maatkit/>.

Please include the complete command-line used to reproduce the problem you are
seeing, the version of all MySQL servers involved, the complete output of the
tool when run with L<"--version">, and if possible, debugging output produced by
running with the C<MKDEBUG=1> environment variable.

=head1 COPYRIGHT, LICENSE AND WARRANTY

This program is copyright 2007-2009 Percona Inc.
and copyright 2006 Proven Scaling LLC and Six Apart Ltd.
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.

=head1 AUTHOR

Proven Scaling LLC, SixApart Ltd, and Baron Schwartz.

=head1 VERSION

This manual page documents Ver 1.0.13 Distrib 3519 $Revision: 3311 $.

=cut
