#!/bin/bash
# +------------------------------------------------------------------+
# |             ____ _               _        __  __ _  __           |
# |            / ___| |__   ___  ___| | __   |  \/  | |/ /           |
# |           | |   | '_ \ / _ \/ __| |/ /   | |\/| | ' /            |
# |           | |___| | | |  __/ (__|   <    | |  | | . \            |
# |            \____|_| |_|\___|\___|_|\_\___|_|  |_|_|\_\           |
# |                                                                  |
# | Copyright Mathias Kettner 2014             mk@mathias-kettner.de |
# +------------------------------------------------------------------+
#
# This file is part of Check_MK.
# The official homepage is at http://mathias-kettner.de/check_mk.
#
# check_mk 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 in version 2.  check_mk is  distributed
# in the hope that it will be useful, but WITHOUT ANY WARRANTY;  with-
# out even the implied warranty of  MERCHANTABILITY  or  FITNESS FOR A
# PARTICULAR PURPOSE. See the  GNU General Public License for more de-
# ails.  You should have  received  a copy of the  GNU  General Public
# License along with GNU Make; see the file  COPYING.  If  not,  write
# to the Free Software Foundation, Inc., 51 Franklin St,  Fifth Floor,
# Boston, MA 02110-1301 USA.

# Try to detect the postgres user
if id pgsql >/dev/null 2>&1; then
    USER=pgsql
elif id postgres >/dev/null 2>&1; then
    USER=postgres
else
    exit 0
fi

echo '<<<postgres_sessions>>>'
# Postgres 9.2 uses 'query' instead of 'current_query'
QNAME="$(echo "select column_name from information_schema.columns where table_name='pg_stat_activity' and column_name in ('query','current_query');" |\
        su - $USER -c "psql -d postgres -t -A -F';'")"
OUTPUT="$(echo "select $QNAME = '<IDLE>', count(*) from pg_stat_activity group by ($QNAME = '<IDLE>');" |\
    su - $USER -c "psql --variable ON_ERROR_STOP=1 -d postgres -A -t -F' '" 2>/dev/null)"

echo "$OUTPUT"
# line with number of idle sessions is sometimes missing on Postgre 8.x. This can lead
# to an altogether empty section and thus the check disappearing.
echo "$OUTPUT" | grep -q '^t ' || echo "t 0"

echo '<<<postgres_stat_database:sep(59)>>>'
echo 'select datid, datname, numbackends, xact_commit, xact_rollback, blks_read, blks_hit, tup_returned, tup_fetched, tup_inserted, tup_updated, tup_deleted, pg_database_size(datname) "datsize" from pg_stat_database;' \
    | su - $USER -c "psql -d postgres -A -F';'" | sed '$d'
