I hope u checked point #11 http://wiki.postgresql.org/wiki/Streaming_Replication#How_to_Use
- *11.* You can calculate the replication lag by comparing the current WAL write location on the primary with the last WAL location received/replayed by the standby. They can be retrieved using * pg_current_xlog_location* on the primary and the * pg_last_xlog_receive_location*/*pg_last_xlog_replay_location* on the standby, respectively. $ psql -c "SELECT pg_current_xlog_location()" -h192.168.0.10 (primary host) pg_current_xlog_location -------------------------- 0/2000000 (1 row) $ psql -c "select pg_last_xlog_receive_location()" -h192.168.0.20 (standby host) pg_last_xlog_receive_location ------------------------------- 0/2000000 (1 row) $ psql -c "select pg_last_xlog_replay_location()" -h192.168.0.20 (standby host) pg_last_xlog_replay_location ------------------------------ 0/2000000 (1 row) Regds Rajesh Kumar Mallah.