Date: Fri, 14 Feb 2025 22:39:45 +0800
From: Julien Rouhaud <rjuju123@gmail.com>
To: Dmitry Dolgov <9erthalion6@gmail.com>
Cc: Sami Imseih <samimseih@gmail.com>,
	=?iso-8859-1?Q?=C1lvaro?= Herrera <alvherre@alvh.no-ip.org>,
	Kirill Reshke <reshkekirill@gmail.com>,
	Sergei Kornilov <sk@zsrv.org>, yasuo.honda@gmail.com,
	tgl@sss.pgh.pa.us, smithpb2250@gmail.com, vignesh21@gmail.com,
	michael@paquier.xyz, nathandbossart@gmail.com, stark.cfm@gmail.com,
	geidav.pg@gmail.com, marcos@f10.com.br, robertmhaas@gmail.com,
	david@pgmasters.net, pgsql-hackers@postgresql.org,
	pavel.trukhanov@gmail.com, Sutou Kouhei <kou@clear-code.com>
Subject: Re: pg_stat_statements and "IN" conditions
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On Fri, Feb 14, 2025 at 03:20:24PM +0100, Dmitry Dolgov wrote:
> 
> Btw, there was another mistake in the last version introducing
> "$1 /*, ... */" format, the constant position has to be of course
> calculated as usual.

I'm not sure what you mean here, but just in case:

> +SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9) AND data = 2;
> + id | data 
> +----+------
> +(0 rows)
> +
> +SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) AND data = 2;
> + id | data 
> +----+------
> +(0 rows)
> +
> +SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11) AND data = 2;
> + id | data 
> +----+------
> +(0 rows)
> +
> +SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
> +                               query                                | calls 
> +--------------------------------------------------------------------+-------
> + SELECT * FROM test_merge WHERE id IN ($1 /*, ... */) AND data = $3 |     3
> + SELECT pg_stat_statements_reset() IS NOT NULL AS t                 |     1
> +(2 rows)

There seems to be an off-by-1 error in parameter numbering when merging them.

Note that the query text as-is can still be successfully be used in an EXPLAIN
(GENERIC_PLAN), but it might cause problem to third party tools that try to do
something smarter about the parameters.