Hi, Here<http://eulerto.blogspot.in/2011/11/understanding-wal-nomenclature.html>is the blog which has good explanation about this.
If you want to find the lag in seconds, then you need to execute something like below. SELECT pg_last_xact_replay_timestamp() - now(); Regards, Dinesh manojadinesh.blogspot.com On Fri, May 16, 2014 at 9:37 PM, J Adams <pacetowns...@gmail.com> wrote: > > Newb question here. I have streaming replication working with 9.2 and I'm > using Bucardo's check_postgres.pl to monitor replication. I see that it > runs this query on the slave: > > SELECT pg_last_xlog_receive_location() AS receive, > pg_last_xlog_replay_location() AS replay > > That returns hex, which is then converted to a number in the script. > > My question is this: what does that number represent? Is it just the log > position? If so, how does the log position translate to queries? Does one > log position = one query? (I did say this was a newb question.) > > How do I determine a meaningful alert threshold for that value? Is there a > reliable way to monitor replication lag in seconds? How do other people > handle this? > >
