From: Tom Lane <tgl@sss.pgh.pa.us>
To: Julien Rouhaud <rjuju123@gmail.com>
Cc: Bruce Momjian <bruce@momjian.us>
Cc: Magnus Hagander <magnus@hagander.net>
Cc: Fujii Masao <masao.fujii@oss.nttdata.com>
Cc: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Subject: Re: compute_query_id and pg_stat_statements
Date: Sun, 25 Apr 2021 11:39:55 -0400
Message-ID: <1934987.1619365195@sss.pgh.pa.us> (raw)
In-Reply-To: <20210425082251.pokyapaxlzdr7k2t@nol>
References: <35457b09-36f8-add3-1d07-6034fa585ca8@oss.nttdata.com>
<20210424152220.GL7629@momjian.us>
<CABUevEx4YQi42MwaMq3Bo09=mBqfjUqtkp5NUZpnQ0HdX+5+Hw@mail.gmail.com>
<20210424170908.GM7629@momjian.us>
<1709439.1619286231@sss.pgh.pa.us>
<20210425082251.pokyapaxlzdr7k2t@nol>
Julien Rouhaud <rjuju123@gmail.com> writes:
> On Sat, Apr 24, 2021 at 01:43:51PM -0400, Tom Lane wrote:
>> I haven't looked, but did we put anything into pg_stat_statements
>> to make it easy to tell if you've messed up this setting?
> You mean apart from from having pg_stat_statements' view/SRFs returning
> nothing?
> I think it's a reasonable use case to sometime disable query_id calculation,
> eg. if you know that it will only lead to useless bloat in the entry and that
> you won't need the info, so spamming warnings if there are no queryid could
> cause some pain.
I agree repeated warnings would be bad news. I was wondering if we could
arrange a single warning at the time pg_stat_statements is preloaded into
the postmaster. In this way, if you tried to use a configuration file
that used to work, you'd hopefully get some notice about why it no longer
does what you want. Also, if you are preloading pg_stat_statements, it
seems reasonable to assume that you'd like the global value of the flag
to be "on", even if there are use-cases for transiently disabling it.
I think the way to detect "being loaded into the postmaster" is
if (IsPostmasterEnvironment && !IsUnderPostmaster)
regards, tom lane
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Cc: tgl@sss.pgh.pa.us, rjuju123@gmail.com, bruce@momjian.us, magnus@hagander.net, masao.fujii@oss.nttdata.com, pgsql-hackers@lists.postgresql.org
Subject: Re: compute_query_id and pg_stat_statements
In-Reply-To: <1934987.1619365195@sss.pgh.pa.us>
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