From: Holger Jakobs <holger@jakobs.com>
To: pgsql-admin@lists.postgresql.org
Subject: Re: Temp files for simple queries
Date: Tue, 22 Jun 2021 13:52:00 +0200
Message-ID: <6ff1c796-9d44-933d-28e1-c02d0b3e86be@jakobs.com> (raw)
In-Reply-To: <45cc44dd-b830-5df5-1f09-171e9874bbc0@gmail.com>
References: <45cc44dd-b830-5df5-1f09-171e9874bbc0@gmail.com>
Default settings might be too low. Try to set work_mem higher. If
operations like sorting don't fit into work_mem, temporary files are used.
Am 22.06.21 um 13:39 schrieb Radoulov, Dimitre:
>
> Hello all,
>
> We have a small Google Cloud SQL PostgreSQL 11 instance.
> The instance is configured with 8G of memory and 4 vCPUs, work_mem is
> 4MB.
>
> I was wondering why the instance uses disk temp files for such a small
> amount of data (see size in the log below)?
>
> I suppose that it's not only the work_mem limit that could trigger
> disk temp file creation or the reported SQL statement is not the only
> one that contributes to it:
>
> I 2021-06-22T09:12:59.164913Z 2021-06-22 09:12:59.163 UTC [1957798]:
> [2-1] db=<db>,user=<user> STATEMENT: SELECT c1, c2 FROM schema1.t1
> WHERE c1 >= $1 ORDER BY c1
> I 2021-06-22T09:12:59.164379Z 2021-06-22 09:12:59.163 UTC [1957798]:
> [1-1] db=<db>,user=<user> LOG: temporary file: path
> "base/pgsql_tmp/pgsql_tmp1957798.0", size 7380992
>
> The t1 table (table and column names have been masked for privacy)
> occupies only 440 kB and has 160 records.
>
>
> Best regards
> Dimitre
>
>
>
--
Holger Jakobs, Bergisch Gladbach, Tel. +49-178-9759012
Attachments:
OpenPGP_signature (application/pgp-signature, 202B) download
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-admin@postgresql.org
Cc: holger@jakobs.com, pgsql-admin@lists.postgresql.org
Subject: Re: Temp files for simple queries
In-Reply-To: <6ff1c796-9d44-933d-28e1-c02d0b3e86be@jakobs.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox