Re: Measurin the lag between a master and a replica

On Thu, Jul 19, 2012 at 7:17 PM, Ali Pouya <alipouya2@gmail.com> wrote:
> On the replica I can use the function pg_last_xact_replay_timestamp().
> But on the master I only can use pg_current_xlog_location() which does not
> return a timestamp. I do not know any function returning the timestamp.
>
> Is there any way to get the timestamp relative to the result of
> pg_current_xlog_location() ?

According to mine own research of this problem there are no way to get it.

What I would do to monitor the replication lag is

1. execute this on master SELECT txid_current(), that will create a
minimal wal entry
2. compare pg_last_xact_replay_timestamp() with current time on replica.

assuming that clocks are in sync on both servers of course.

--
Sergey Konoplev

a database architect, software developer at PostgreSQL-Consulting.com
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