From: Radoulov, Dimitre <cichomitiko@gmail.com>
To: pgsql-admin@lists.postgresql.org
Subject: Temp files for simple queries
Date: Tue, 22 Jun 2021 13:39:11 +0200
Message-ID: <45cc44dd-b830-5df5-1f09-171e9874bbc0@gmail.com> (raw)
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
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