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Thread: Check replication lag

Check replication lag

From
Sreejith P
Date:

Hi,

 

Am using SELECT (now() - pg_last_xact_replay_timestamp()) < '1’) min for identifying replication lag. Is there any better option available in postgres 10.

 

IN SYNC mode of replication what would be the impact on Master DB server in terms of over all performance  ?

 

 

 

 

 

Thanks

Sreejith.


 

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Re: Check replication lag

From
Thomas Munro
Date:
On Thu, Aug 6, 2020 at 7:02 AM Sreejith P <sreejith@lifetrenz.com> wrote:
> IN SYNC mode of replication what would be the impact on Master DB server in terms of over all performance  ?

The pg_stat_replication columns write_lag, flush_lag and replay_lag
are designed tell you how long to expect commits to take for
synchronous standbys, based on recent history, if synchronous_commit
it set to remote_write, on or remote_apply respectively.  Those times
tell you about commit latency, which limits sequential commit rate for
each session.