From: | David Rowley <david(dot)rowley(at)2ndquadrant(dot)com> |
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To: | Andreas Seltenreich <andreas(dot)seltenreich(at)credativ(dot)de> |
Cc: | PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
Subject: | Re: Excessive memory usage in multi-statement queries w/ partitioning |
Date: | 2019-05-23 08:47:48 |
Message-ID: | CAKJS1f_aY0Vka-TpAMoL366-npbZddRSZfXACk=jf+N0cRszhg@mail.gmail.com |
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On Thu, 23 May 2019 at 17:55, Andreas Seltenreich
<andreas(dot)seltenreich(at)credativ(dot)de> wrote:
> a customer reported excessive memory usage and out-of-memory ERRORs
> after introducing native partitioning in one of their databases. We
> could narrow it down to the overhead introduced by the partitioning when
> issuing multiple statements in a single query.
"multiple statements in a single query", did you mean to write session
or maybe transaction there?
Which version?
I tried your test case with REL_11_STABLE and I see nowhere near as
much memory used in MessageContext.
After repeating the query twice, I see:
MessageContext: 8388608 total in 11 blocks; 3776960 free (1 chunks);
4611648 used
Grand total: 8388608 bytes in 11 blocks; 3776960 free (1 chunks); 4611648 used
MessageContext: 8388608 total in 11 blocks; 3776960 free (1 chunks);
4611648 used
Grand total: 8388608 bytes in 11 blocks; 3776960 free (1 chunks); 4611648 used
which is quite a long way off the 252MB you're getting.
perhaps I'm not testing with the same version as you are.
--
David Rowley http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
Attachment | Content-Type | Size |
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dump_MessageContext_stats.diff | application/octet-stream | 458 bytes |
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