From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: Dmitry Dolgov <9erthalion6@gmail.com>, Zhihong Yu <zyu@yugabyte.com>,
        David Steele <david@pgmasters.net>,
        PostgreSQL-development <pgsql-hackers@postgresql.org>,
        Greg Stark <stark@mit.edu>,
        Pavel Trukhanov <pavel.trukhanov@gmail.com>
Subject: Re: pg_stat_statements and "IN" conditions
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Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
	message dated "Mon, 14 Mar 2022 11:02:16 -0400"
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Date: Mon, 14 Mar 2022 11:23:17 -0400
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Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Mar 14, 2022 at 10:57 AM Dmitry Dolgov <9erthalion6@gmail.com> w=
rote:
>> I'm not sure if I follow the last point. WHERE x in (1,3) and x =3D
>> any(array[1,3]) are two different things for sure, but in which way are
>> they going to be mixed together because of this change? My goal was to
>> make only the following transformation, without leaving any uncertainty=
:
>> =

>> WHERE x in (1, 2, 3, 4, 5) -> WHERE x in (1, 2, ...)
>> WHERE x =3D any(array[1, 2, 3, 4, 5]) -> WHERE x =3D any(array[1, 2, ..=
.])

> I understand. I think it might be OK to transform both of those
> things, but I don't think it's very clear either from the comments or
> the nonexistent documentation that both of those cases are affected --
> and I think that needs to be clear.

We've transformed IN(...) to ANY(ARRAY[...]) at the parser stage for a
long time, and this has been visible to users of either EXPLAIN or
pg_stat_statements for the same length of time.  I doubt people are
going to find that surprising.  Even if they do, it's not the query
jumbler's fault.

I do find it odd that the proposed patch doesn't cause the *entire*
list to be skipped over.  That seems like extra complexity and confusion
to no benefit.

			regards, tom lane