Re: Managing autovacuum freezing - Mailing list pgsql-admin

From Don Seiler
Subject Re: Managing autovacuum freezing
Date
Msg-id CAHJZqBBSDtNMXyVKeXdb_Oz4B+AGCLgG5ZR2dKCoTUmZ558ozA@mail.gmail.com
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In response to Re: Managing autovacuum freezing  (Peter Geoghegan <pg@bowt.ie>)
Responses Re: Managing autovacuum freezing
List pgsql-admin
On Thu, Feb 11, 2021 at 11:49 AM Peter Geoghegan <pg@bowt.ie> wrote:
On Thu, Feb 11, 2021 at 9:13 AM Don Seiler <don@seiler.us> wrote:
> My understanding is that these manual VACUUM ANALYZE jobs are not freezing rows that regular autovacuuming would otherwise be doing, which leads up to the big anti-wraparound job.

They will freeze rows, but not aggressively. The antiwraparound vacuum
might block on acquiring buffer pins, low level stuff like that.

Perhaps you should change the vacuum_index_cleanup reloption to 'off'
for the table, but make the scripted overnight vacuums directly
specify INDEX_CLEANUP=on. That way index cleanup would still be
performed for the vacuums that run overnight, though not for the
antiwraparound vacuums, where the overhead may be a real issue.

Thanks for the response, Peter. This table *does* have 14 indexes on it as well, including on GIN index (rest are btree, some are partial indexes). I've had a separate task on the back burner to try to identify any redundant ones.

In the scenario you describe, would we re-enable the routine autovacuuming? I'm assuming so but wanted to make it clear.

Cheers,
Don. 


--
Don Seiler
www.seiler.us

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