Horton

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

Julien Rouhaud <rjuju123@gmail.com>

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From: Julien Rouhaud <rjuju123@gmail.com>
To: Bruce Momjian <bruce@momjian.us>
Cc: Hannu Krosing <hannuk@google.com>, Robert Haas <robertmhaas@gmail.com>, Pavel Stehule <pavel.stehule@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Michael Paquier <michael@paquier.xyz>, torikoshia <torikoshia@oss.nttdata.com>, Atsushi Torikoshi <atorik@gmail.com>, Tatsuro Yamada <tatsuro.yamada.tf@nttcom.co.jp>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Evgeny Efimkin <efimkin@yandex-team.ru>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-03-20T06:12:34Z
Lists: pgsql-hackers

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On Fri, Mar 19, 2021 at 12:53:18PM -0400, Bruce Momjian wrote:
> 
> Well, given we don't really want to support multiple query id types
> being generated or displayed, the "error out" above should fix it. 
> 
> Let's do this --- tell extensions to error out if the query id is
> already set, either by compute_query_id or another extension.  If an
> extension wants to generate its own query id and store is internal to
> the extension, that is fine, but the server-displayed query id should be
> generated once and never overwritten by an extension.

Agreed, this will ensure that you won't dynamically change the queryid source.

We should also document that changing it requires a restart and calling
pg_stat_statements_reset() afterwards.

v19 adds some changes, plus extra documentation for pg_stat_statements about
the requirement for a queryid to be calculated, and a note that all documented
details only apply for in-core source.  I'm not sure if this is still the best
place to document those details anymore though.

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'