Date: Wed, 21 Apr 2021 09:53:38 -0500
From: Justin Pryzby <pryzby@telsasoft.com>
To: Fujii Masao <masao.fujii@oss.nttdata.com>
Cc: Pavel Stehule <pavel.stehule@gmail.com>, Peter Geoghegan <pg@bowt.ie>,
	Julien Rouhaud <rjuju123@gmail.com>,
	"Tharakan, Robins" <tharar@amazon.com>,
	pgsql-hackers@postgresql.org
Subject: Re: track_planning causing performance regression
Message-ID: <20210421145338.GT7256@telsasoft.com>
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On Wed, Apr 21, 2021 at 11:38:52PM +0900, Fujii Masao wrote:
> On 2021/04/19 23:55, Justin Pryzby wrote:
> > What does "kind" mean ?  I think it means a "normalized" query or a "query
> > structure".
> > 
> > "a fewer kinds" is wrong, so I think the docs should say "a small number of
> > queries" or maybe:
> 
> Okay, I agree to update the description.
> 
> > > > >       Enabling this parameter may incur a noticeable performance penalty,
> > > > >       especially similar queries are run by many concurrent connections and
> > > > >       compete to update the same pg_stat_statements entry
> 
> "a small number of" is better than "similar" at the above because
> "similar" sounds a bit unclear in this case?
> 
> It's better to use "entries" rather than "entry" at the above?

How about like this?

       Enabling this parameter may incur a noticeable performance penalty,
-      especially when a fewer kinds of queries are executed on many
+      especially when queries with the same queryid are executed by many
       concurrent connections.

Or:

       Enabling this parameter may incur a noticeable performance penalty,
       especially similar queries are executed by many concurrent connections
       and compete to update a small number of pg_stat_statements entries.

-- 
Justin