From: | Michael Paquier <michael(at)paquier(dot)xyz> |
---|---|
To: | pgsql-committers(at)lists(dot)postgresql(dot)org |
Subject: | pgsql: doc: Mention de-normalization of deallocated entries in pg_stat_ |
Date: | 2023-03-01 01:56:19 |
Message-ID: | E1pXBha-001Gil-LQ@gemulon.postgresql.org |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-committers |
doc: Mention de-normalization of deallocated entries in pg_stat_statements
The current implementation of query normalization in pg_stat_statements
is optimistic. If an entry is deallocated between the post-analyze hook
and the planner and/or execution hook, it can be possible to find query
strings with literal constant values (like "SELECT 1, 2") rather than
their normalized flavor (like "SELECT $1, $2").
This commit adds in the documentation a paragraph about this limitation,
and that this risk can be reduced by increasing pg_stat_statements.max,
particularly if pg_stat_statements_info reports a high number of
deallocations.
Author: Sami Imseih
Discussion: https://postgr.es/m/9CFF3512-355B-4676-8CCC-6CF622F4DC1A@amazon.com
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/6da67a0c111a29e876b7172d081c7d152d23ea3d
Modified Files
--------------
doc/src/sgml/pgstatstatements.sgml | 10 ++++++++++
1 file changed, 10 insertions(+)
From | Date | Subject | |
---|---|---|---|
Next Message | Peter Eisentraut | 2023-03-01 07:11:54 | pgsql: meson: Add equivalent of configure --disable-rpath option |
Previous Message | Michael Paquier | 2023-03-01 01:32:24 | pgsql: doc: Update pg_stat_statements about query ID calculation of uti |