Horton

Re: Berserk Autovacuum (let's save next Mandrill)

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Dean Rasheed <dean.a.rasheed@gmail.com>
Cc: David Rowley <dgrowleyml@gmail.com>, Laurenz Albe <laurenz.albe@cybertec.at>, Andres Freund <andres@anarazel.de>, Alexander Korotkov <a.korotkov@postgrespro.ru>, Justin Pryzby <pryzby@telsasoft.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Masahiko Sawada <masahiko.sawada@2ndquadrant.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Amit Kapila <amit.kapila16@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Darafei Komяpa Praliaskouski <me@komzpa.net>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Michael Banck <mbanck@gmx.net>
Date: 2020-03-31T21:16:39Z
Lists: pgsql-hackers 
I wrote:
> Dean Rasheed <dean.a.rasheed@gmail.com> writes:
>> I had a go at reproducing this. I wasn't able to produce the reported
>> failure, but I can reliably produce an Assert failure that may be
>> related by doing a VACUUM FULL simultaneously with an ANALYZE that is
>> generating extended stats, which produces:
>> ...
>> It looks to me as though the problem is that statext_store() needs to
>> take its lock on pg_statistic_ext_data *before* searching for the
>> stats tuple to update.

> Hmm, yeah, that seems like clearly a bad idea.

I pushed a fix for that, but I think it must be unrelated to the
buildfarm failures we're seeing.  For that coding to be a problem,
it would have to run concurrently with a VACUUM FULL or CLUSTER
on pg_statistic_ext_data (which would give all the tuples new TIDs).
AFAICS that won't happen with the tests that are giving trouble.

			regards, tom lane

Commits

  1. Further improve stability fix for partition_aggregate test.

  2. Improve stability fix for partition_aggregate test.

  3. Attempt to stabilize partitionwise_aggregate test

  4. Fix race condition in statext_store().

  5. Attempt to fix unstable regression tests, take 2

  6. Attempt to fix unstable regression tests

  7. Trigger autovacuum based on number of INSERTs

  8. Fix upper limit for vacuum_cleanup_index_scale_factor