Re: vacuumdb idle processes - Mailing list pgsql-admin

From Nikhil Shetty
Subject Re: vacuumdb idle processes
Date
Msg-id CAFpL5VwDxPpwuMxzOAMo7cYfgNsMzBU2ob_N7xcsDS_VBgyF-Q@mail.gmail.com
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In response to Re: vacuumdb idle processes  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: vacuumdb idle processes
List pgsql-admin
Hi Tom,

Apparently not all that well, if it failed to keep us out of an
autovacuum-to-prevent-wraparound situation.  I suppose you had autovacuum
disabled because you thought this lashup was sufficient?

 No, autovacuum was enabled but seems it was not able to catch up with the amount of transaction or it might have been delayed due to postgres favouring other txns that conflict -- Need to check this though

Perhaps this is the last remaining table so vacuumdb has nothing
else for them to do.

Does this mean vacuumdb will release all db connections(jobs - 8 in this case) only  after all connections have performed their vacuum and then disconnected? Even if one is pending the others will be still connected but in idle state? Is my understanding correct?

Thanks and Regards,
Nikhil

On Sat, Jun 12, 2021 at 12:03 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
Nikhil Shetty <nikhil.dba04@gmail.com> writes:
> I have done a setup to run vacuumdb with 8 parallel jobs daily. It has been
> running quite well.

Apparently not all that well, if it failed to keep us out of an
autovacuum-to-prevent-wraparound situation.  I suppose you had autovacuum
disabled because you thought this lashup was sufficient?

> Just today I saw there is an aggressive autovacuum process running(to
> prevent wraparound) on one of the table. vacuumdb which started later
> spawned the 8 connections. One connection (doing vacuum on the table on
> which an aggressive autovacuum is running) is waiting for "autovacuum(to
> prevent wraparound)" to complete while the other 7 connections are just
> sitting idle.

> I am okay that one connection is waiting since an aggressive autovacuum is
> running on that table but how come other connections have not released the
> sesion yet? Any reason for this?

Perhaps this is the last remaining table so vacuumdb has nothing
else for them to do.

                        regards, tom lane

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