On Tue, Jan 14, 2014 at 2:31 PM, Granthana Biswas <granth...@zedo.com>wrote:
> Can anyone please tell me which of the following is the correct > replication lag query to find streaming replication lag in seconds? > > IMHO none is 'correct'. :-) 1. SELECT extract(seconds from (now() - pg_last_xact_replay_timestamp())) > AS time_lag; > > This is the difference between now and last replayed log. What if the last transaction on master has happened a few minutes ago? > 2. SELECT CASE WHEN pg_last_xlog_receive_location() = > pg_last_xlog_replay_location() THEN 0 ELSE EXTRACT (EPOCH FROM now() - > pg_last_xact_replay_timestamp()) END AS log_delay; > For reason same as above, this won't be exact but the most accurate you can get. Best Regards, *Sameer Kumar | Database Consultant* *ASHNIK PTE. LTD.*101 Cecil Street, #11-11 Tong Eng Building, Singapore 069533 M : *+65 8110 0350 <%2B65%208110%200350>* T: +65 6438 3504 | www.ashnik.com www.facebook.com/ashnikbiz | www.twitter.com/ashnikbiz [image: email patch] This email may contain confidential, privileged or copyright material and is solely for the use of the intended recipient(s).
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