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postgres_streaming_
Name
postgres_streaming_ - Plugin to monitor PostgreSQL streaming replication lag.
Configuration
The configuration for the database connections need to be made in pg_service.conf (see the PostgreSQL documentation). To specify which cluster to monitor, link this plugin to postgres_streaming_<master>:<slave>, where <master> and <slave> are the names of the services specified in pg_service.conf.
See Also
Magic Markers
#%# family=manual
Author
Magnus Hagander magnus@hagander.net, Redpill Linpro AB
Copyright/License.
Copyright (c) 2010 Magnus Hagander, Redpill Linpro AB
All rights reserved. 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 dated June, 1991.
#!@@PERL@@
# -*- cperl -*-
# vim: ft=perl
#
# Copyright (C) 2010 Magnus Hagander, Redpill Linpro AB
#
# 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 dated June,
# 1991.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# 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., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301 USA.
=head1 NAME
postgres_streaming_ - Plugin to monitor PostgreSQL streaming replication lag.
=head1 CONFIGURATION
The configuration for the database connections need to be made in
pg_service.conf (see the PostgreSQL documentation). To specify which
cluster to monitor, link this plugin to
postgres_streaming_<master>:<slave>, where <master> and <slave> are
the names of the services specified in pg_service.conf.
=head1 SEE ALSO
=head1 MAGIC MARKERS
#%# family=manual
=head1 AUTHOR
Magnus Hagander <magnus@hagander.net>, Redpill Linpro AB
=head1 COPYRIGHT/License.
Copyright (c) 2010 Magnus Hagander, Redpill Linpro AB
All rights reserved. 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
dated June, 1991.
=cut
use strict;
use warnings;
use bigint;
use DBI;
use DBD::Pg;
if (defined $ARGV[0] && $ARGV[0] ne '') {
if ($ARGV[0] eq 'autoconf') {
print "no (autoconf not supported)\n";
exit(1);
}
elsif ($ARGV[0] eq 'config') {
print "graph_title PostgreSQL replication lag\n";
print "graph_vlabel Lag (kb xlog)\n";
print "graph_category PostgreSQL\n";
print "graph_info PostgreSQL streaming replication lag\n";
print "graph_args --base 1024\n";
print "receive.label Receive delay\n";
print "receive.type GAUGE\n";
print "receive.draw LINE1\n";
print "receive.min 0\n";
print "apply.label Apply delay\n";
print "apply.type GAUGE\n";
print "apply.draw LINE1\n";
print "apply.min 0\n";
exit(0);
}
else {
print "Unknown command: '$ARGV[0]'\n";
exit(1);
}
}
# Process!
unless ($0 =~ /postgres_streaming_([^:]+):([^:]+)$/) {
print "Invalid link: $0. Must be postgres_streaming_<master>:<slave>\n";
exit(2);
}
my $master = $1;
my $slave = $2;
my $dbmaster = DBI->connect("DBI:Pg:service=$master") or die "Could not connect to master at $master\n";
my $dbslave = DBI->connect("DBI:Pg:service=$slave") or die "Could not connect to slave at $slave\n";
my $masterdata;
my $slavedata;
# PostgreSQL 10 renamed the WAL status functions as follows:
#
# - pg_current_xlog_location() -> pg_current_wal_lsn()
# - pg_last_xlog_receive_location() -> pg_last_wal_receive_lsn()
# - pg_last_xlog_replay_location() -> pg_last_wal_replay_lsn()
#
(my $pg_maj_ver) = $dbmaster->{pg_server_version} =~ /(\d+)(\d){2,2}(\d){2,2}$/;
if ($pg_maj_ver < 10) {
$masterdata = $dbmaster->selectall_arrayref("SELECT pg_current_xlog_location()") or die "Could not query for xlog location on master\n";
$slavedata = $dbslave->selectall_arrayref("SELECT pg_last_xlog_receive_location(), pg_last_xlog_replay_location()") or die "Could not query for xlog locations on slave\n";
} else {
$masterdata = $dbmaster->selectall_arrayref("SELECT pg_current_wal_lsn()") or die "Could not query for WAL location on master\n";
$slavedata = $dbslave->selectall_arrayref("SELECT pg_last_wal_receive_lsn(), pg_last_wal_replay_lsn()") or die "Could not query for WAL locations on slave\n";
}
$dbmaster->disconnect();
$dbslave->disconnect();
my $master_num = CalculateNumericalOffset($masterdata->[0]->[0]);
my $receive_delay = ($master_num - CalculateNumericalOffset($slavedata->[0]->[0]));
my $replay_delay = ($master_num - CalculateNumericalOffset($slavedata->[0]->[1]));
print "receive.value $receive_delay\n";
print "apply.value $replay_delay\n";
exit(0);
sub CalculateNumericalOffset
{
my $stringofs = shift;
my @pieces = split /\//, $stringofs;
die "Invalid offset: $stringofs" unless ($#pieces == 1);
# First part is logid, second part is record offset
return (hex("ff000000") * hex($pieces[0])) + hex($pieces[1]);
}