Horton

Re: Feature improvement: can we add queryId for pg_catalog.pg_stat_activity view?

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Julien Rouhaud <julien.rouhaud@free.fr>
Cc: Evgeny Efimkin <efimkin@yandex-team.ru>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2019-11-11T08:37:30Z
Lists: pgsql-hackers 
On Wed, Sep 11, 2019 at 06:30:22PM +0200, Julien Rouhaud wrote:
> The thing is that pg_stat_statements assigns a 0 queryid in the
> post_parse_analyze_hook to recognize utility statements and avoid
> tracking instrumentation twice in case of utility statements, and then
> compute a queryid base on a hash of the query text.  Maybe we could
> instead fully reserve queryid "2" for utility statements (so forcing
> queryid "1" for standard queries if jumbling returns 0 *or* 2 instead
> of only 0), and use "2" as the identifier for utility statement
> instead of "0"?

Hmm.  Not sure.  At this stage it would be nice to gather more input
on the matter, and FWIW, I don't like much the assumption that a query
ID of 0 is perhaps a utility statement, or perhaps nothing depending
on the state of a backend entry, or even perhaps something else
depending how on how modules make use and define such query IDs.
--
Michael

Commits

  1. Clarify description of pg_stat_statements columns

  2. Fix wording in description of pg_stat_statements.toplevel

  3. Mention that toplevel is part of pg_stat_statements key.

  4. adjust query id feature to use pg_stat_activity.query_id

  5. Update copyright for 2021

  6. Take the statistics collector out of the loop for monitoring backends'