Re: Correct query to check streaming replication lag

[Granthana Biswas <granthana@xxxxxxxx>]

Yes it's purely for monitoring purpose.

Regards,

Granthana

On Fri, Jan 17, 2014 at 3:29 PM, Sameer Kumar <sameer.kumar@xxxxxxxxxx> wrote:

On Fri, Jan 17, 2014 at 5:31 PM, Granthana Biswas <granthana@xxxxxxxx> wrote:

Thank you Sameer for your reply. Is there any other query that would help get exact replication lag?

You 2nd Query is the most accurate you can get. 

 

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.

You can get lags in terms of bytes (and I have always believed that makes more sense).

May I ask, why are you looking for this info? Is it purely monitoring?

Regards

Sameer

Ashnik Pte Ltd.