Subject: Re: compute_query_id and pg_stat_statements
To: Julien Rouhaud <rjuju123@gmail.com>, Michael Paquier <michael@paquier.xyz>
Cc: Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>,
 Alvaro Herrera <alvherre@alvh.no-ip.org>, Stephen Frost
 <sfrost@snowman.net>, Magnus Hagander <magnus@hagander.net>,
 Bruce Momjian <bruce@momjian.us>, Christoph Berg <myon@debian.org>,
 Peter Eisentraut <peter.eisentraut@enterprisedb.com>,
 PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
References: <2268611.1619458140@sss.pgh.pa.us>
 <20210426174331.GA19401@alvherre.pgsql>
 <20210426181408.3j6kkzpxnadpwptv@alap3.anarazel.de>
 <2295572.1619461260@sss.pgh.pa.us>
 <20210426183745.4gd2s5qra6mlxfto@alap3.anarazel.de>
 <20210427062504.ofz3rgedbrl5bep2@nol> <YJoeXcrwe1EDmqKT@paquier.xyz>
 <20210511073539.vw4m46vvbqhiwnz5@nol>
From: Fujii Masao <masao.fujii@oss.nttdata.com>
Message-ID: <4f0929bf-c690-f2be-a050-a69a47a79651@oss.nttdata.com>
Date: Tue, 11 May 2021 17:41:53 +0900
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On 2021/05/11 16:35, Julien Rouhaud wrote:
> Anyway, PFA a patch that implement a [off | on | auto] compute_query_id, and
> provides a new queryIdWanted() function to let third party plugins inform us
> that they want a query id if possible.

Thanks!


> As it was noted somewhere in that thread, that's a hack on top on the GUC
> machinery, so compute_query_id will display "on" rather than "auto" (or "auto
> and enabled" or whatever) since GUC isn't designed to handle that behavior.

Can't we work around this issue by making queryIdWanted() set another flag like query_id_wanted instead of overwriting compute_query_id? If we do this, query id computation is necessary when "compute_query_id == COMPUTE_QUERY_ID_ON || (compute_query_id == COMPUTE_QUERY_ID_AUTO && query_id_wanted)".

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION