Re: Postgres Replaying WAL slowly

On Jun 30, 2014, at 1:39 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:

>
>
>> Another item of note is the system catalogs are quite bloated:
>> Would that cause the replica to spin on StandbyReleaseLocks?
>
> AFAIK, no.  It's an unsurprising consequence of heavy use of short-lived
> temp tables though.
>

Yah, this has been an issue in the past, so we tend to cluster them regularly during off-hours to minimize the issue.

> So it seems like we have a candidate explanation.  I'm a bit surprised
> that StandbyReleaseLocks would get this slow if there are only a dozen
> AccessExclusiveLocks in place at any one time, though.  Perhaps that
> was a low point and there are often many more?
>
>

Entirely possible that it was a low point.  We'll set up some monitoring to track the number of AccessExclusiveLocks
andsee how much variance there is throughout the day.