#!/bin/bash
#
# Plugin to monitor PostgreSQL Locks
#
# Author:
#    Guilherme Augusto da Rocha Silva <gars.dba@gmail.com>
#
# Created:
#    5th of november 2007
#
# Modified:
#    22th of September 2011 by Nozomu Kaneko <nozom.kaneko@gmail.com>
#
# Usage:
#    Place in /etc/munin/plugins/ (or link it there using ln -s)
#
# Parameters:
#    config   (required)
#
# General info:
#    Require permission for database access and read (no writes are processed).
#    Recommended user is PostgreSQL database owner (default: postgres).
#
# Log info:
#

dbserver='localhost'
dbuser='postgres'

modes="AccessExclusive AccessShare Exclusive RowExclusive RowShare Share ShareRowExclusive ShareUpdateExclusive"

if [ "$1" = "config" ]; then
   echo 'graph_args --lower-limit 0'
   echo 'graph_category Postgresql'
   echo 'graph_info Shows active locks on database server.'
   echo 'graph_scale no'
   echo 'graph_title PostgreSQL Active Locks'
   echo 'graph_vlabel Number of active locks'
   for mode in $modes; do
     echo $mode.label $mode
     echo $mode.info `echo $mode | perl -pe 's/(.)([A-Z])/$1 $2/g'` Lock.
   done
   exit 0
fi

for mode in $modes; do
   eval ${mode}=0
done

eval $(psql -h ${dbserver} -U ${dbuser} template1 -tc "SELECT trim(mode, 'Lock'), COUNT(*) FROM pg_locks GROUP BY mode ORDER BY 1;" | while read name sep num
do
   test -z "${name}" && continue
   echo ${name}=${num}
done)

for mode in $modes; do
   echo ${mode}.value $(eval echo \$$mode)
done