Обсуждение: Default maximum time replication between master and slave databases

On Jul 10, 2015, at 6:54 AM, Alberto Olivares <alberto.olivares@snowflakesoftware.com> wrote:
>
> SELECT EXTRACT (epoch from now() - pg_last_xact_replay_timestamp());
>
> The maximum result is 60 seconds then the value goes to 0 and start again. I would like to modify this value to
maximum30 seconds. 
>
> I have tried to change different parameters on the  postgresql.conf in both databases but I have not find the
solution.

WAL shipping or streaming?

--
Scott Ribe
scott_ribe@elevated-dev.com
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(303) 722-0567 voice

Hi

Le 10 juil. 2015 2:58 PM, "Alberto Olivares" <alberto.olivares@snowflakesoftware.com> a écrit :
>
> Hello,
>
> I am running this query in the slave database: 
>
> SELECT EXTRACT (epoch from now() - pg_last_xact_replay_timestamp());
>
> The maximum result is 60 seconds then the value goes to 0 and start again. I would like to modify this value to maximum 30 seconds.
>
> I have tried to change different parameters on the  postgresql.conf in both databases but I have not find the solution.
>
> Anyone knows how to change this default value?
>

pg_last_xact_replay_timestamp() gives you the timestamp of the last replayed transaction. That doesn't have anything to do with configuration. It mostly depends on the activity on the master. If you don't have any write activity on the master, you'll have bigger values. And that's normal.

--
Guillaume

Le 10 juil. 2015 4:07 PM, "Alberto Olivares" <alberto.olivares@snowflakesoftware.com> a écrit :
>
> Hi,
>
> I don't have any write activity on the master, but still this value goes to 60 seconds and then restart constantly from 0 again . 
>

Well, you have. That might be autovacuum doing some vacuum or analyze without you noticing it.

--
Guillaume