From: Joe Conway <mail@joeconway.com>
To: David Rowley <david.rowley@2ndquadrant.com>
Cc: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
Cc: Andreas Seltenreich <andreas.seltenreich@credativ.de>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Excessive memory usage in multi-statement queries w/ partitioning
Date: Fri, 24 May 2019 10:17:21 -0400
Message-ID: <db7efe35-03eb-e715-9766-d564dc479f0b@joeconway.com> (raw)
In-Reply-To: <CAKJS1f-StHT8ZKyC8rsK=nJim13qDWDiNO8NMirTBo_jk=z5Aw@mail.gmail.com>
References: <87ftp6l2qr.fsf@credativ.de>
<e0ec915a-ebd3-ee9d-144b-e24bc3fae3c4@lab.ntt.co.jp>
<0e717312-3a02-781b-7dfc-e0cc395e92d8@joeconway.com>
<CAKJS1f-StHT8ZKyC8rsK=nJim13qDWDiNO8NMirTBo_jk=z5Aw@mail.gmail.com>
On 5/24/19 9:33 AM, David Rowley wrote:
> On Sat, 25 May 2019 at 00:18, Joe Conway <mail@joeconway.com> wrote:
>> I admittedly haven't followed this thread too closely, but if having 100
>> partitions causes out of memory on pg11, that sounds like a massive
>> regression to me.
>
> For it to have regressed it would have had to once have been better,
> but where was that mentioned? The only thing I saw was
> non-partitioned tables compared to partitioned tables, but you can't
> really say it's a regression if you're comparing apples to oranges.
I have very successfully used multiple hundreds and even low thousands
of partitions without running out of memory under the older inheritance
based "partitioning", and declarative partitioning is supposed to be
(and we have advertised it to be) better, not worse, isn't it?
At least from my point of view if 100 partitions is unusable due to
memory leaks it is a regression. Perhaps not *technically* a regression
assuming it behaves this way in pg10 also, but I bet lots of users would
see it that way.
Joe
--
Crunchy Data - http://crunchydata.com
PostgreSQL Support for Secure Enterprises
Consulting, Training, & Open Source Development
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Cc: mail@joeconway.com, david.rowley@2ndquadrant.com, Langote_Amit_f8@lab.ntt.co.jp, andreas.seltenreich@credativ.de, pgsql-hackers@lists.postgresql.org
Subject: Re: Excessive memory usage in multi-statement queries w/ partitioning
In-Reply-To: <db7efe35-03eb-e715-9766-d564dc479f0b@joeconway.com>
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