From: Fujii Masao <masao.fujii@oss.nttdata.com>
To: Julien Rouhaud <rjuju123@gmail.com>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: Pavel Stehule <pavel.stehule@gmail.com>
Cc: Peter Geoghegan <pg@bowt.ie>
Cc: Tharakan, Robins <tharar@amazon.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: track_planning causing performance regression
Date: Thu, 1 Jul 2021 17:28:30 +0900
Message-ID: <c162e1b3-08b0-2216-8e9e-80733d4a1a9b@oss.nttdata.com> (raw)
In-Reply-To: <CAOBaU_YJUNCPuEAciSmFBS0EJ16Qa_pDH3mLjSpUnG4FtaSbzg@mail.gmail.com>
References: <646e5cae-5e8b-feaa-43dc-014bf355bf08@oss.nttdata.com>
<20210418233615.GB7256@telsasoft.com>
<d4cb31e2-d43f-0811-8f10-cf8e2f052e5e@oss.nttdata.com>
<20210419145545.GF7256@telsasoft.com>
<b86e33bf-d549-db6b-f50b-3cb077807a71@oss.nttdata.com>
<20210421145338.GT7256@telsasoft.com>
<f2aa2d6a-3b78-0526-4ca5-8ace10eb745e@oss.nttdata.com>
<20210421154007.GU7256@telsasoft.com>
<20210629020918.GE21248@telsasoft.com>
<CAOBaU_bg0OcRUykMP=_XY7tsBfjtq1NW=JeO5=p=QRg8hXAT1A@mail.gmail.com>
<20210629024535.GG21248@telsasoft.com>
<CAOBaU_YJUNCPuEAciSmFBS0EJ16Qa_pDH3mLjSpUnG4FtaSbzg@mail.gmail.com>
On 2021/06/30 0:12, Julien Rouhaud wrote:
>> Enabling this parameter may incur a noticeable performance penalty,
>> - especially when a fewer kinds of queries are executed on many
>> - concurrent connections.
>> + especially when queries with identical structure are executed by many
>> + concurrent connections which compete to update a small number of
>> + pg_stat_statements entries.
>>
>> It could say "identical structure" or "the same queryid" or "identical queryid".
>
> I think we should try to reuse the previous formulation. How about
> "statements with identical query structure"?
I'm fine with this. So what about the following diff? I added <structname> tag.
<varname>pg_stat_statements.track_planning</varname> controls whether
planning operations and duration are tracked by the module.
Enabling this parameter may incur a noticeable performance penalty,
- especially when a fewer kinds of queries are executed on many
- concurrent connections.
+ especially when statements with identical query structure are executed
+ by many concurrent connections which compete to update a small number of
+ <structname>pg_stat_statements</structname> entries.
The default value is <literal>off</literal>.
Only superusers can change this setting.
Regards,
--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION
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To: pgsql-hackers@postgresql.org
Cc: masao.fujii@oss.nttdata.com, rjuju123@gmail.com, pryzby@telsasoft.com, pavel.stehule@gmail.com, pg@bowt.ie, tharar@amazon.com
Subject: Re: track_planning causing performance regression
In-Reply-To: <c162e1b3-08b0-2216-8e9e-80733d4a1a9b@oss.nttdata.com>
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