From: Bruce Momjian <bruce@momjian.us>
To: Julien Rouhaud <rjuju123@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: Pavel Stehule <pavel.stehule@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Michael Paquier <michael@paquier.xyz>
Cc: torikoshia <torikoshia@oss.nttdata.com>
Cc: Atsushi Torikoshi <atorik@gmail.com>
Cc: Tatsuro Yamada <tatsuro.yamada.tf@nttcom.co.jp>
Cc: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: Evgeny Efimkin <efimkin@yandex-team.ru>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Feature improvement: can we add queryId for pg_catalog.pg_stat_activity view?
Date: Thu, 18 Mar 2021 09:47:29 -0400
Message-ID: <20210318134729.GA8529@momjian.us> (raw)
In-Reply-To: <20210317232956.veah6bax3mespdtq@nol>
References: <20210317151701.GA16650@momjian.us>
<3518601.1615994918@sss.pgh.pa.us>
<20210317154023.GB16650@momjian.us>
<3519983.1615996898@sss.pgh.pa.us>
<CAFj8pRBwOBo_3R3zNc+E2Z+skzRd+dwNVRLfn95R2P=qscp-SQ@mail.gmail.com>
<20210317162444.GD16650@momjian.us>
<20210317164907.c4uogoqvchnwcnjy@nol>
<CA+Tgmoa5r2yxtuyHiYM3dVVEorr3vbVexYm9m+maMMiZtA25uA@mail.gmail.com>
<20210317223216.GE16650@momjian.us>
<20210317232956.veah6bax3mespdtq@nol>
On Thu, Mar 18, 2021 at 07:29:56AM +0800, Julien Rouhaud wrote:
> On Wed, Mar 17, 2021 at 06:32:16PM -0400, Bruce Momjian wrote:
> > OK, is that what everyone wants? I think that is what the patch already
> > does.
>
> Note exactly. Right now a custom queryid can be computed even if
> compute_queryid is off, if some extension does that in post_parse_analyze_hook.
>
> I'm assuming that what Robert was thinking was more like:
>
> if (compute_queryid)
> {
> if (queryid_hook)
> queryId = queryid_hook(...);
> else
> queryId = JumbeQuery(...);
> }
> else
> queryId = 0;
>
> And that should be done *after* post_parse_analyse_hook so that it's clear that
> this hook is no longer the place to compute queryid.
>
> Is that what should be done?
No, I don't think so. I think having extensions change behavior
controlled by GUCs is a bad interface.
The docs are going to say that you have to enable compute_queryid to see
the query id in pg_stat_activity and log_line_prefix, but if you install
an extension, the query id will be visible even if you don't have
compute_queryid enabled. I think you need to only honor the hook if
compute_queryid is enabled, and update the pg_stat_statements docs to
say you have to enable compute_queryid for pg_stat_statements to work.
Also, should it be compute_queryid or compute_query_id?
Also, the overhead of computing the query id was reported as 2% --- that
seems quite high for what it does. Do we know why it is so high?
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EDB https://enterprisedb.com
If only the physical world exists, free will is an illusion.
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To: pgsql-hackers@postgresql.org
Cc: bruce@momjian.us, rjuju123@gmail.com, robertmhaas@gmail.com, pavel.stehule@gmail.com, tgl@sss.pgh.pa.us, alvherre@alvh.no-ip.org, michael@paquier.xyz, torikoshia@oss.nttdata.com, atorik@gmail.com, tatsuro.yamada.tf@nttcom.co.jp, tomas.vondra@2ndquadrant.com, efimkin@yandex-team.ru, pgsql-hackers@lists.postgresql.org
Subject: Re: Feature improvement: can we add queryId for pg_catalog.pg_stat_activity view?
In-Reply-To: <20210318134729.GA8529@momjian.us>
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