Update comment and README.md file

README

@@ -1,74 +0,0 @@
-Nagios plugin to check Postgres Streaming replication
-=====================================================
-
-This script could be used as Nagios check plugin to verify Postgres Streaming
-replication state.
-
-This script :
-
-- check if Postgres is running (CRITICAL raise if not)
-- check if Postgres is in recovery mode :
-  - if Postgres is in recovery mode :
-    - retreive from Postgres the last xlog file receive and the xlog file replay
-    - check if Postgres recovery configuration file is NOT present (CRITICAL
-      raise if present)
-    - retreive master connection informations from Postgres recovery configuration
-      file (UNKNOWN raise on error). Default Postgres master TCP port will be used
-      if port is not specify.
-    - retreive  current xlog file from Postgres master server (UNKNOWN raise on error).
-    - check if the last receive xlog file is the last replay xlog file (WARNING raise if not)
-    - Return OK state
-- if Postgres is not in recovery mode :
-  - check if Postgres recovery configuration file is present (CRITICAL raise if present)
-  - check if stand-by client(s) is connected (WARNING raise if not)
-  - Return OK state with list and count of stand-by client(s)
-
-Note : This script was originally write and test for PostgreSQL 9.1, but it could be compatible
-with other versions of PostgreSQL. Do not hesitate to tell me how this script work with other
-versions and share some fix. All contributions are welcome !
-
-Requirements
-------------
-
- * On master node :
-
-     Slaves node must be able to connect with user PG_USER to database postgres as trust.
-
- * On standby node :
-
-     PG_USER must be able to connect localy as trust
-
-Usage
------
-
-    Usage : ./check_pg_streaming_replication [-h] [-d] [options]
-	-u pg_user		Specify Postgres user (Default : postgres)
-	-b psql_bin		Specify psql binary path (Default : /usr/bin/psql)
-	-m pg_main		Specify Postgres main directory path
-				(Default : /var/lib/postgresql/9.1/main)
-	-r recovery_conf	Specify Postgres recovery configuration file path
-				(Default : /var/lib/postgresql/9.1/main/recovery.conf)
-	-p pg_port		Specify default Postgres master TCP port (Default : 5432)
-	-d			Debug mode
-	-h 			Show this message
-
-Copyright
----------
-
-Copyright (c) 2013 Benjamin Renard 
-
-License
--------
-
-This program is free software; you can redistribute it and/or
-modify it under the terms of the GNU General Public License version 2
-as published by the Free Software Foundation.
-
-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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

README.md

@@ -0,0 +1,76 @@
+Nagios plugin to check Postgres Streaming replication
+=====================================================
+
+This script could be used as Nagios check plugin to verify Postgres Streaming replication state.
+
+This script :
+
+- check if Postgres is running (_CRITICAL_ raise if not)
+- check if Postgres is in recovery mode :
+  - if Postgres is in recovery mode :
+    - retreive from Postgres the last _xlog_ file receive and the _xlog_ file replay
+    - check if Postgres recovery configuration file is NOT present (_CRITICAL_ raise if present)
+    - retreive master connection informations from Postgres recovery configuration file (_UNKNOWN_ raise on error). Default Postgres master TCP port will be used if port is not specify.
+    - retreive the current state and sync state of the host from Postgres master server by making a connection on master server (_UNKNOWN_ raise on error).
+    - check if the current state of the host is "streaming" (_CRITICAL_ raise if not)
+    - check if the current sync state of the host is "sync" (_CRITICAL_ raise if not)
+    - if the check of the current XLOG file of the master host is enabled :
+      - retreive current _xlog_ file from Postgres master server by making a connection on master server (_UNKNOWN_ raise on error).
+      - check if the current master _xlog_ file is the last received _xlog_ file (_CRITICAL_ raise if not)
+    - check if the last received _xlog_ file is the last replay _xlog_ file : if not, check the current delay with the last replayed transaction against _replay_warn_delay_ and _replay_crit_delay_ thresholds and raise corresponding error if they are exceeded
+    - Return _OK_ state
+  - if Postgres is not in recovery mode :
+    - check if Postgres recovery configuration file is present (_CRITICAL_ raise if present)
+    - check if stand-by client(s) is connected (_WARNING_ raise if not)
+    - Return _OK_ state with list and count of stand-by client(s)
+
+**Note :** This script was originally write for PostgreSQL 9.1 and test on 9.1, 9.5 and 9.6 but it could be compatible with other versions of PostgreSQL. Some adjustments have been made for PostgreSQL >= 10 (without testing it). Do not hesitate to tell me how this script work with other versions and share some fix. All contributions are welcome !
+
+Requirements
+------------
+
+* Some CLI tools: `sudo`, `awk`, `sed`, `bc`, `psql` and `pg_lscluster`
+
+* **On master node:** Slaves must be able to connect with user from `recovery.conf` (or user specify using `-U`) to database with the same name (or another specified with `-D`) as `trust` (or via `md5` using password specified in `~/.pgpass`). This user must have `SUPERUSER` privilege (need to get replication details).
+
+* **On standby node:** `PG_USER` must be able to connect localy on the database with the same name `(or another specified with -D)` as `trust` (or via `md5` using password specified in `~/.pgpass`).
+
+Usage
+-----
+
+```
+Usage: check_pg_streaming_replication [-d] [-h] [options]
+	-u pg_user		Specify local Postgres user (Default: try to auto-detect or use postgres)
+	-b psql_bin		Specify psql binary path (Default: /usr/bin/psql)
+	-B pg_lsclusters_bin	Specify pg_lsclusters binary path (Default: /usr/bin/pg_lsclusters)
+	-V pg_version		Specify Postgres version (Default: try to auto-detect or use 9.1)
+	-m pg_main		Specify Postgres main directory path (Default: try to auto-detect or use
+                                /var/lib/postgresql//main)
+	-r recovery_conf	Specify Postgres recovery configuration file path
+				(Default: [PG_MAIN]/recovery.conf)
+	-U pg_master_user	Specify Postgres user to use on master (Default: user from recovery.conf file)
+	-p pg_port		Specify default Postgres master TCP port (Default: same as local PostgreSQL
+	                        port if detected or use 5432)
+	-D dbname		Specify DB name on Postgres master/slave to connect on (Default: PG_USER, must
+	                        match with .pgpass one is used)
+	-C 1/0			Enable or disable check if the current LSN of the master host is the same
+				of the last received LSN (Default: 1)
+	-w replay_warn_delay	Specify the replay warning delay in second (Default: 3)
+	-c replay_crit_delay	Specify the replay critical delay in second (Default: 5)
+	-d			Debug mode
+	-h 			Show this message
+```
+
+Copyright
+---------
+
+Copyright (c) 2014-2020 Benjamin Renard
+
+License
+-------
+
+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, either version 3 of the License, or (at your option) any later version.
+
+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, see <https://www.gnu.org/licenses/>.

check_pg_streaming_replication

@@ -1,51 +1,77 @@
 #!/bin/bash
 #
 # Nagios plugin to check Postgresql streamin replication state
-# 
+#
 # Could be use on Master or on standby node
 #
-# Requirement : 
+# Requirements:
 #
-#     On master node : Slaves must be able to connect with user PG_USER
-#                      to database postgres as trust
+#     Some CLI tools: sudo, awk, sed, bc, psql and pg_lscluster
 #
-#     On standby node : PG_USER must be able to connect localy as trust
+#     On master node: Slaves must be able to connect with user from recovery.conf
+#                     (or user specify using -U) to database with the same name
+#                     (or another specified with -D) as trust (or via md5 using
+#                     password specified in ~/.pgpass). This user must have
+#                     SUPERUSER privilege (need to get replication details).
 #
-# Author : Benjamin Renard <brenard@easter-eggs.com>
-# Date : Wed, 14 Mar 2012 14:45:55 +0000
-# Source : http://git.zionetrix.net/check_pg_streaming_replication
+#     On standby node: PG_USER must be able to connect localy on the database
+#                      with the same name (or another specified with -D) as trust
+#                      (or via md5 using password specified in ~/.pgpass).
+#
+# Author: Benjamin Renard <brenard@easter-eggs.com>
+# Date: Wed, 04 Nov 2020 15:31:13 +0100
+# Source: https://gogs.zionetrix.net/bn8/check_pg_streaming_replication
+# SPDX-License-Identifier: GPL-3.0-or-later
 #
 
-PG_USER=postgres
+DEFAULT_PG_USER=postgres
+DEFAULT_PG_VERSION=9.1
+DEFAULT_PG_MAIN=/var/lib/postgresql/$PG_VERSION/main
+DEFAULT_PG_PORT=5432
+PG_USER=""
+PG_VERSION=""
+PG_MAIN=""
+PG_MASTER_USER=""
 PSQL_BIN=/usr/bin/psql
-PG_MAIN=/var/lib/postgresql/9.1/main
-if [ -f /etc/redhat-release ]
-then
-	PG_MAIN=/var/lib/pgsql/9.1/data
-fi
+PG_LSCLUSTER_BIN=/usr/bin/pg_lsclusters
 RECOVERY_CONF_FILENAME=recovery.conf
 RECOVERY_CONF=""
-PG_DEFAULT_PORT=5432
+PG_DEFAULT_PORT=""
+PG_DEFAULT_APP_NAME=$( hostname )
+PG_DB=""
+CHECK_CUR_MASTER_LSN=1
+REPLAY_WARNING_DELAY=3
+REPLAY_CRITICAL_DELAY=5
 
 DEBUG=0
 
 function usage () {
 	cat << EOF
-Usage : $0 [-d] [-h] [options]
-	-u pg_user		Specify Postgres user (Default : $PG_USER)
-	-b psql_bin		Specify psql binary path (Default : $PSQL_BIN)
-	-m pg_main		Specify Postgres main directory path
-				(Default : $PG_MAIN)
+Usage: $0 [-d] [-h] [options]
+	-u pg_user		Specify local Postgres user (Default: try to auto-detect or use $DEFAULT_PG_USER)
+	-b psql_bin		Specify psql binary path (Default: $PSQL_BIN)
+	-B pg_lsclusters_bin	Specify pg_lsclusters binary path (Default: $PG_LSCLUSTER_BIN)
+	-V pg_version		Specify Postgres version (Default: try to auto-detect or use $DEFAULT_PG_VERSION)
+	-m pg_main		Specify Postgres main directory path (Default: try to auto-detect or use
+                                $DEFAULT_PG_MAIN)
 	-r recovery_conf	Specify Postgres recovery configuration file path
-				(Default : $PG_MAIN/$RECOVERY_CONF_FILENAME)
-	-p pg_port		Specify default Postgres master TCP port (Default : $PG_DEFAULT_PORT)
+				(Default: [PG_MAIN]/$RECOVERY_CONF_FILENAME)
+	-U pg_master_user	Specify Postgres user to use on master (Default: user from recovery.conf file)
+	-p pg_port		Specify default Postgres master TCP port (Default: same as local PostgreSQL
+	                        port if detected or use $DEFAULT_PG_PORT)
+	-D dbname		Specify DB name on Postgres master/slave to connect on (Default: PG_USER, must
+	                        match with .pgpass one is used)
+	-C 1/0			Enable or disable check if the current LSN of the master host is the same
+				of the last received LSN (Default: $CHECK_CUR_MASTER_LSN)
+	-w replay_warn_delay	Specify the replay warning delay in second (Default: $REPLAY_WARNING_DELAY)
+	-c replay_crit_delay	Specify the replay critical delay in second (Default: $REPLAY_CRITICAL_DELAY)
 	-d			Debug mode
 	-h 			Show this message
 EOF
 	exit 0
 }
 
-while getopts "hu:b:m:r:p:d" OPTION
+while getopts "hu:b:B:V:m:r:U:p:D:C:w:c:d" OPTION
 do
 	case $OPTION in
 		u)
@@ -54,15 +80,36 @@ do
 		b)
 			PSQL_BIN=$OPTARG
 		;;
+		B)
+			PG_LSCLUSTER_BIN=$OPTARG
+		;;
+		V)
+			PG_VERSION=$OPTARG
+		;;
 		m)
 			PG_MAIN=$OPTARG
 		;;
 		r)
 			RECOVERY_CONF=$OPTARG
 		;;
+		U)
+			PG_MASTER_USER=$OPTARG
+		;;
 		p)
 			PG_DEFAULT_PORT=$OPTARG
 		;;
+		D)
+			PG_DB=$OPTARG
+		;;
+		C)
+			CHECK_CUR_MASTER_LSN=$OPTARG
+		;;
+		w)
+			REPLAY_WARNING_DELAY=$OPTARG
+		;;
+		c)
+			REPLAY_CRITICAL_DELAY=$OPTARG
+		;;
 		d)
 			DEBUG=1
 		;;
@@ -75,40 +122,116 @@ do
 	esac
 done
 
+function debug() {
+	if [ $DEBUG -eq 1 ]
+	then
+		>&2 echo -e "[DEBUG] $1"
+	fi
+}
+
+debug "Starting options (before handling auto-detection/default values):
+PG_VERSION = $PG_VERSION
+PG_DB = $PG_DB
+PG_USER = $PG_USER
+PSQL_BIN = $PSQL_BIN
+PG_LSCLUSTER_BIN = $PG_LSCLUSTER_BIN
+PG_MAIN = $PG_MAIN
+RECOVERY_CONF = $RECOVERY_CONF
+PG_DEFAULT_PORT = $PG_DEFAULT_PORT
+PG_DEFAULT_APP_NAME = $PG_DEFAULT_APP_NAME
+CHECK_CUR_MASTER_LSN = $CHECK_CUR_MASTER_LSN
+REPLAY_WARNING_DELAY = $REPLAY_WARNING_DELAY
+REPLAY_CRITICAL_DELAY = $REPLAY_CRITICAL_DELAY
+"
+
+# Auto-detect PostgreSQL information using pg_lsclusters
+if [ -x "$PG_LSCLUSTER_BIN" ]
+then
+	PG_CLUSTER=$( $PG_LSCLUSTER_BIN -h 2>/dev/null|head -n1 )
+	if [ -n "$PG_CLUSTER" ]
+	then
+		debug "pg_lsclusters output:\n\t$PG_CLUSTER"
+		# Output example:
+		# 9.6 main    5432 online,recovery postgres /var/lib/postgresql/9.6/main /var/log/postgresql/postgresql-9.6-main.log
+		[ -z "$PG_VERSION" ] && PG_VERSION=$( echo "$PG_CLUSTER"|awk -F ' +' '{print $1}' )
+		[ -z "$PG_DEFAULT_PORT" ] && PG_DEFAULT_PORT=$( echo "$PG_CLUSTER"|awk -F ' +' '{print $3}' )
+		[ -z "$PG_USER" ] && PG_USER=$( echo "$PG_CLUSTER"|awk -F ' +' '{print $5}' )
+		[ -z "$PG_MAIN" ] && PG_MAIN=$( echo "$PG_CLUSTER"|awk -F ' +' '{print $6}' )
+	fi
+else
+	debug "pg_lsclusters not found ($PG_LSCLUSTER_BIN): parameters auto-detection disabled"
+fi
+
+# If auto-detection failed, use default values
+[ -z "$PG_USER" ] && PG_USER="$DEFAULT_PG_USER"
+[ -z "$PG_VERSION" ] && PG_VERSION="$DEFAULT_PG_VERSION"
+[ -z "$PG_MAIN" ] && PG_MAIN="$DEFAULT_PG_MAIN"
+[ -z "$PG_DEFAULT_PORT" ] && PG_DEFAULT_PORT="$DEFAULT_PG_PORT"
+
 # Check PG_USER
-[ -z "$PG_USER" ] && echo "UNKNOWN : Postgres user not specify" && exit 3
+[ -z "$PG_USER" ] && echo "UNKNOWN: Postgres user not specified" && exit 3
 id "$PG_USER" > /dev/null 2>&1
-[ $? -ne 0 ] && echo "UNKNOWN : Invalid Postgres user ($PG_USER)" && exit 3
+[ $? -ne 0 ] && echo "UNKNOWN: Invalid Postgres user ($PG_USER)" && exit 3
 
 # Check PSQL_BIN
-[ ! -x "$PSQL_BIN" ] && echo "UNKNOWN : Invalid psql bin path ($PSQL_BIN)" && exit 3
+[ ! -x "$PSQL_BIN" ] && echo "UNKNOWN: Invalid psql bin path ($PSQL_BIN)" && exit 3
 
 # Check PG_MAIN
-[ ! -d "$PG_MAIN/" ] && echo "UNKNOWN : Invalid Postgres main directory path ($PG_MAIN)" && exit 3
+[ ! -d "$PG_MAIN/" ] && echo "UNKNOWN: Invalid Postgres main directory path ($PG_MAIN)" && exit 3
 
 # Check RECOVERY_CONF
 [ -z "$RECOVERY_CONF" ] && RECOVERY_CONF="$PG_MAIN/$RECOVERY_CONF_FILENAME"
 
 # Check PG_DEFAULT_PORT
-[ $( echo "$PG_DEFAULT_PORT"|grep -c -E '^[0-9]*$' ) -ne 1 ] && "UNKNOWN : Postgres default master TCP port must be an integer." && exit 3
+[ $( echo "$PG_DEFAULT_PORT"|grep -c -E '^[0-9]*$' ) -ne 1 ] && "UNKNOWN: Postgres default master TCP port must be an integer." && exit 3
+
+# If PG_DB is not provided with -D parameter, use PG_USER as default value
+[ -z "$PG_DB" ] && PG_DB="$PG_USER"
 
 function psql_get () {
-	echo "$1"|su - $PG_USER -c "$PSQL_BIN -t -P format=unaligned"
+	sql="$1"
+	debug "Exec 'echo \"$sql\"|sudo -u $PG_USER $PSQL_BIN -d \"$PG_DB\" -w -t -P format=unaligned"
+	echo "$sql"|sudo -u $PG_USER $PSQL_BIN -d "$PG_DB" -w -t -P format=unaligned
 }
 
-function debug() {
-	if [ $DEBUG -eq 1 ]
-	then
-		echo "[DEBUG] $1"
-	fi
+function psql_master_get () {
+	sql="$1"
+	debug "Exec 'echo \"$sql\"|sudo -u $PG_USER $PSQL_BIN -U $M_USER -h $M_HOST -w -p $M_PORT -d $PG_DB -t -P format=unaligned"
+	echo "$sql"|sudo -u $PG_USER $PSQL_BIN -U $M_USER -h $M_HOST -w -p $M_PORT -d $PG_DB -t -P format=unaligned
 }
 
-debug "Running options :
+debug "Running options:
+PG_VERSION = $PG_VERSION
+PG_DB = $PG_DB
 PG_USER = $PG_USER
 PSQL_BIN = $PSQL_BIN
+PG_LSCLUSTER_BIN = $PG_LSCLUSTER_BIN
 PG_MAIN = $PG_MAIN
 RECOVERY_CONF = $RECOVERY_CONF
-PG_DEFAULT_PORT = $PG_DEFAULT_PORT"
+PG_DEFAULT_PORT = $PG_DEFAULT_PORT
+PG_DEFAULT_APP_NAME = $PG_DEFAULT_APP_NAME
+CHECK_CUR_MASTER_LSN = $CHECK_CUR_MASTER_LSN
+REPLAY_WARNING_DELAY = $REPLAY_WARNING_DELAY
+REPLAY_CRITICAL_DELAY = $REPLAY_CRITICAL_DELAY
+"
+
+# Set some stuff to PostgreSQL version
+if [ $( echo "$PG_VERSION < 10" |bc -l ) -eq 1 ]
+then
+	pg_last_wal_receive_lsn='pg_last_xlog_receive_location()'
+	pg_last_wal_replay_lsn='pg_last_xlog_replay_location()'
+	pg_current_wal_lsn='pg_current_xlog_location()'
+	pg_wal_lsn_diff='pg_xlog_location_diff'
+	sent_lsn='sent_location'
+	write_lsn='write_location'
+else
+	pg_last_wal_receive_lsn='pg_last_wal_receive_lsn()'
+	pg_last_wal_replay_lsn='pg_last_wal_replay_lsn()'
+	pg_current_wal_lsn='pg_current_wal_lsn()'
+	pg_wal_lsn_diff='pg_wal_lsn_diff'
+	sent_lsn='sent_lsn'
+	write_lsn='write_lsn'
+fi
 
 # Postgres is running ?
 if [ $DEBUG -eq 0 ]
@@ -119,13 +242,13 @@ else
 fi
 if [ $? -ne 0 ]
 then
-	echo "CRITICAL : Postgres is not running !"
+	echo "CRITICAL: Postgres is not running !"
 	exit 2
 fi
 debug "Postgres is running"
 
 RECOVERY_MODE=0
-[ $( psql_get 'SELECT pg_is_in_recovery();' ) == "t" ] && RECOVERY_MODE=1
+[ "$( psql_get 'SELECT pg_is_in_recovery();' )" == "t" ] && RECOVERY_MODE=1
 
 if [ -f $RECOVERY_CONF ]
 then
@@ -134,69 +257,148 @@ then
 	# Check recovery mode
 	if [ $RECOVERY_MODE -ne 1 ]
 	then
-		echo "CRITICAL : Not in recovery mode while recovery.conf file found !"
+		echo "CRITICAL: Not in recovery mode while recovery.conf file found !"
 		exit 2
 	fi
 	debug "Postgres is in recovery mode"
 
-	LAST_XLOG_RECEIVE=$( psql_get "SELECT pg_last_xlog_receive_location()" )
-	debug "Last xlog file receive : $LAST_XLOG_RECEIVE"
-	LAST_XLOG_REPLAY=$( psql_get "SELECT pg_last_xlog_replay_location()" )
-	debug "Last xlog file replay : $LAST_XLOG_REPLAY"
+	# Get local current last received/replayed LSN
+	LAST_RECEIVED_LSN=$( psql_get "SELECT $pg_last_wal_receive_lsn" )
+	debug "Last received LSN: $LAST_RECEIVED_LSN"
+	LAST_REPLAYED_LSN=$( psql_get "SELECT $pg_last_wal_replay_lsn" )
+	debug "Last replayed LSN: $LAST_REPLAYED_LSN"
 
 
 	# Get master connection informations from recovery.conf file
-	MASTER_CONN_INFOS=$( egrep '^ *primary_conninfo' $RECOVERY_CONF|sed "s/^ *primary_conninfo *= *[\"\']\([^\"\']*\)[\"\'].*$/\1/" )
+	MASTER_CONN_INFOS=$( egrep '^ *primary_conninfo' $RECOVERY_CONF|sed "s/^ *primary_conninfo *= *\(.\+\) *$/\1/" )
 	if [ ! -n "$MASTER_CONN_INFOS" ]
 	then
-		echo "UNKNOWN : Can't retreive master connection informations form recovery.conf file"
+		echo "UNKNOWN: Can't retreive master connection informations form recovery.conf file"
 		exit 3
 	fi
-	debug "Master connection informations : $MASTER_CONN_INFOS"
+	debug "Master connection informations: $MASTER_CONN_INFOS"
 
-	M_HOST=$( echo "$MASTER_CONN_INFOS"|sed 's/^.*host= *\([^ ]*\) *.*$/\1/' )
+	M_HOST=$( echo "$MASTER_CONN_INFOS"| grep 'host=' | sed 's/^.*host= *\([0-9a-zA-Z.-]\+\) *.*$/\1/' )
 	if [ ! -n "$M_HOST" ]
 	then
-		echo "UNKNOWN : Can't retreive master host from recovery.conf file"
+		echo "UNKNOWN: Can't retreive master host from recovery.conf file"
 		exit 3
 	fi
-	debug "Master host : $M_HOST"
+	debug "Master host: $M_HOST"
 
-	M_PORT=$( echo "$MASTER_CONN_INFOS"|sed 's/^.*port= *\([^ ]*\) *.*$/\1/' )
+	M_PORT=$( echo "$MASTER_CONN_INFOS"| grep 'port=' | sed 's/^.*port= *\([0-9a-zA-Z.-]\+\) *.*$/\1/' )
 	if [ ! -n "$M_PORT" ]
 	then
-		debug "Master port not specify, use default : $PG_DEFAULT_PORT"
+		debug "Master port not specified, use default: $PG_DEFAULT_PORT"
 		M_PORT=$PG_DEFAULT_PORT
 	else
-		debug "Master port : $M_PORT"
+		debug "Master port: $M_PORT"
 	fi
-	
-	# Get current xlog file from master
-	M_CUR_XLOG="$( echo 'SELECT pg_current_xlog_location()'|su - $PG_USER -c "$PSQL_BIN -h $M_HOST -p $M_PORT -t -P format=unaligned" )"
-	if [ ! -n "$M_CUR_XLOG" ]
+
+	if [ -n "$PG_MASTER_USER" ]
 	then
-		echo "UNKNOWN : Can't retreive current xlog from master server"
+		debug "Master user provided by command-line, use it: $PG_MASTER_USER"
+		M_USER="$PG_MASTER_USER"
+	else
+		M_USER=$( echo "$MASTER_CONN_INFOS"| grep 'user=' | sed 's/^.*user= *\([0-9a-zA-Z.-]\+\) *.*$/\1/' )
+		if [ ! -n "$M_USER" ]
+		then
+			debug "Master user not specified, use default: $PG_USER"
+			M_USER=$PG_USER
+		else
+			debug "Master user: $M_USER"
+		fi
+	fi
+
+	M_APP_NAME=$( echo "$MASTER_CONN_INFOS"| grep 'application_name=' | sed "s/^.*application_name=[ \'\"]*\([^ \'\"]\+\)[ \'\"]*.*$/\1/" )
+	if [ ! -n "$M_APP_NAME" ]
+	then
+		debug "Master application name not specified, use default: $PG_DEFAULT_APP_NAME"
+		M_APP_NAME=$PG_DEFAULT_APP_NAME
+	else
+		debug "Master application name: $M_APP_NAME"
+	fi
+
+	# Get current replication state information from master
+	M_CUR_REPL_STATE_INFO="$( psql_master_get "SELECT state, sync_state, $sent_lsn AS sent_lsn, $write_lsn AS write_lsn FROM pg_stat_replication WHERE application_name='$M_APP_NAME';" )"
+	if [ ! -n "$M_CUR_REPL_STATE_INFO" ]
+	then
+		echo "UNKNOWN: Can't retreive current replication state information from master server"
 		exit 3
 	fi
-	debug "Master current xlog : $M_CUR_XLOG"
+	debug "Master current replication state:\n\tstate|sync_state|sent_lsn|write_lsn\n\t$M_CUR_REPL_STATE_INFO"
 
-	# Master current xlog is the last receive xlog ?
-	if [ "$M_CUR_XLOG" != "$LAST_XLOG_RECEIVE" ]
+	M_CUR_STATE=$( echo "$M_CUR_REPL_STATE_INFO"|cut -d'|' -f1 )
+	debug "Master current state: $M_CUR_STATE"
+	if [ "$M_CUR_STATE" != "streaming" ]
 	then
-		echo "CRITICAL : Master current xlog is not the last receive xlog"
+		echo "CRITICAL: this host is not in streaming state according to master host (current state = '$M_CUR_STATE')"
 		exit 2
 	fi
-	debug "Master current xlog is the last receive xlog"
 
-	# The last receive xlog is the last replay file ?
-	if [ "$LAST_XLOG_RECEIVE" != "$LAST_XLOG_REPLAY" ]
+	M_CUR_SYNC_STATE=$( echo "$M_CUR_REPL_STATE_INFO"|cut -d'|' -f2 )
+	debug "Master current sync state: $M_CUR_SYNC_STATE"
+	if [ "$M_CUR_SYNC_STATE" != "sync" ]
 	then
-		echo "WARNING : last receive xlog file is not the last replay file"
+		echo "CRITICAL: this host is not synchronized according to master host (current sync state = '$M_CUR_SYNC_STATE')"
+		exit 2
+	fi
+
+	M_CUR_SENT_LSN=$( echo "$M_CUR_REPL_STATE_INFO"|cut -d'|' -f3 )
+	M_CUR_WRITED_LSN=$( echo "$M_CUR_REPL_STATE_INFO"|cut -d'|' -f4 )
+	debug "Master current last sent/writed LSN: '$M_CUR_SENT_LSN' / '$M_CUR_WRITED_LSN'"
+
+	# Check current master LSN vs last received LSN
+	if [ "$CHECK_CUR_MASTER_LSN" == "1" ]
+	then
+		# Get current LSN from master
+		M_CUR_LSN="$( psql_master_get "SELECT $pg_current_wal_lsn" )"
+		if [ ! -n "$M_CUR_LSN" ]
+		then
+			echo "UNKNOWN: Can't retreive current LSN from master server"
+			exit 3
+		fi
+		debug "Master current LSN: $M_CUR_LSN"
+
+		# Master current LSN is the last received LSN ?
+		if [ "$M_CUR_LSN" != "$LAST_RECEIVED_LSN" ]
+		then
+			echo "CRITICAL: Master current LSN is not the last received LSN"
+			exit 2
+		fi
+		debug "Master current LSN is the last received LSN"
+	fi
+
+	# The last received LSN is the last replayed ?
+	if [ "$LAST_RECEIVED_LSN" != "$LAST_REPLAYED_LSN" ]
+	then
+		debug "/!\ The last received LSN is NOT the last replayed LSN ('$M_CUR_LSN' / '$LAST_REPLAYED_LSN')"
+		REPLAY_DELAY="$( psql_get 'SELECT EXTRACT(EPOCH FROM now() - pg_last_xact_replay_timestamp());' )"
+		debug "Replay delay is $REPLAY_DELAY second(s)"
+		if [ $( echo "$REPLAY_DELAY >= $REPLAY_CRITICAL_DELAY"|bc -l ) -gt 0 ]
+		then
+			echo "CRITICAL: last received LSN is not the last replayed ('$LAST_RECEIVED_LSN' / '$LAST_REPLAYED_LSN') and replay delay is $REPLAY_DELAY second(s)"
+			exit 2
+		fi
+		if [ $( echo "$REPLAY_DELAY >= $REPLAY_WARNING_DELAY"|bc -l ) -gt 0 ]
+		then
+			echo "WARNING: last received LSN is not the last replay file ('$LAST_RECEIVED_LSN' / '$LAST_REPLAYED_LSN') and replay delay is $REPLAY_DELAY second(s)"
+			exit 1
+		fi
+		debug "Replay delay is not worrying"
+	fi
+	debug "Last received LSN is the last replayed file"
+
+	# The master last sent LSN is the last received (and synced) ?
+	if [ "$M_CUR_SENT_LSN" != "$LAST_RECEIVED_LSN" ]
+	then
+		echo "WARNING: master last sent LSN is not already received (and synced to disk) by slave. May be we have some network delay or load on slave"
+		echo "Master last sent LSN: $M_CUR_SENT_LSN"
+		echo "Slave last received (and synced to disk) LSN: $LAST_RECEIVED_LSN"
 		exit 1
 	fi
-	debug "Last receive xlog file is the last replay file"
 
-	echo "OK : Hot-standby server is uptodate"
+	echo "OK: Hot-standby server is uptodate"
 	exit 0
 else
 	debug "File recovery.conf not found. Master mode."
@@ -204,31 +406,65 @@ else
 	# Check recovery mode
 	if [ $RECOVERY_MODE -eq 1 ]
 	then
-		echo "CRITICAL : In recovery mode while recovery.conf file not found !"
+		echo "CRITICAL: In recovery mode while recovery.conf file not found !"
 		exit 2
 	fi
 	debug "Postgres is not in recovery mode"
 
+	# Retreive current lsn
+	CURRENT_LSN=$( psql_get "SELECT $pg_current_wal_lsn" )
+	if [ -z "$CURRENT_LSN" ]
+	then
+		echo "UNKNOWN: Fail to retreive current LSN (Log Sequence Number)"
+		exit 3
+	fi
+	debug "Current LSN: $CURRENT_LSN"
+
 	# Check standby client
-	STANDBY_CLIENTS=$( psql_get "SELECT client_addr, sync_state FROM pg_stat_replication;" )
+	STANDBY_CLIENTS=$( psql_get "SELECT application_name, client_addr, sent_lsn, write_lsn, state, sync_state, current_lag
+	FROM (
+	  SELECT application_name, client_addr, sent_lsn, write_lsn, state, sync_state, current_lag
+	  FROM (
+	    SELECT application_name, client_addr, $sent_lsn AS sent_lsn, $write_lsn AS write_lsn, state, sync_state,
+	      $pg_wal_lsn_diff($pg_current_wal_lsn, $write_lsn) AS current_lag
+	    FROM pg_stat_replication
+	  ) AS s2
+	) AS s1" )
 	if [ ! -n "$STANDBY_CLIENTS" ]
 	then
-		echo "WARNING : no stand-by client connected"
+		echo "WARNING: no stand-by client connected"
 		exit 1
 	fi
-	debug "Stand-by client(s) : $( echo  -n $STANDBY_CLIENTS|sed 's/\n/ , /g' )"
+	debug "Stand-by client(s):\n\t$( echo -e "$STANDBY_CLIENTS"|sed 's/\n/\n\t/' )"
 
 	STANDBY_CLIENTS_TXT=""
 	STANDBY_CLIENTS_COUNT=0
+	CURRENT_LSN_IS_LAST_SENT=1
 	for line in $STANDBY_CLIENTS
 	do
 		let STANDBY_CLIENTS_COUNT=STANDBY_CLIENTS_COUNT+1
 
-		IP=$( echo $line|cut -d '|' -f 1 )
-		MODE=$( echo $line|cut -d '|' -f 2 )
-		STANDBY_CLIENTS_TXT="$STANDBY_CLIENTS_TXT $IP (mode=$MODE)"
+		NAME=$( echo $line|cut -d '|' -f 1 )
+		IP=$( echo $line|cut -d '|' -f 2 )
+		SENT_LSN=$( echo $line|cut -d '|' -f 3 )
+		WRITED_LSN=$( echo $line|cut -d '|' -f 4 )
+		STATE=$( echo $line|cut -d '|' -f 5 )
+		SYNC_STATE=$( echo $line|cut -d '|' -f 6 )
+		LAG=$( echo $line|cut -d '|' -f 7 )
+		STANDBY_CLIENTS_TXT="$STANDBY_CLIENTS_TXT\n$NAME ($IP): $STATE/$SYNC_STATE (LSN: sent='$SENT_LSN' / writed='$WRITED_LSN', Lag: ${LAG}b)"
+		[ "$SENT_LSN" != "$CURRENT_LSN" ] && CURRENT_LSN_IS_LAST_SENT=0
 	done
 
-	echo "OK : $STANDBY_CLIENTS_COUNT stand-by client(s) connected - $STANDBY_CLIENTS_TXT"
-	exit 0
+	if [ $CURRENT_LSN_IS_LAST_SENT -eq 1 ]
+	then
+		echo "OK: $STANDBY_CLIENTS_COUNT stand-by client(s) connected"
+		EXIT_CODE=0
+	else
+		echo "WARNING: current master LSN is not the last sent to stand-by client(s) connected. May be we have some load ?"
+		EXIT_CODE=1
+	fi
+
+	echo "Current master LSN: $CURRENT_LSN"
+	echo -e "$STANDBY_CLIENTS_TXT"
+	exit $EXIT_CODE
 fi