From: Antonin Houska <ah@cybertec.at>
To: Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
cc: asp437@gmail.com, a.bykov@postgrespro.ru,
    pgsql-hackers@lists.postgresql.org
Subject: Re: Optimze usage of immutable functions as relation
In-reply-to: <20181024.120245.134697149.horiguchi.kyotaro@lab.ntt.co.jp>
References: <20180906185109.661aaef0@asp437-ThinkPad-L380>
 <153994199621.10161.17815885396545049364.pgcf@coridan.postgresql.org>
 <CACdpekK1oDy7-_HnXOaREa_8HM2r-fsp8iv5e6p8aWOdGdK8Mg@mail.gmail.com>
 <20181024.120245.134697149.horiguchi.kyotaro@lab.ntt.co.jp>
Comments: In-reply-to Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
   message dated "Wed, 24 Oct 2018 12:02:45 +0900."
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Date: Thu, 08 Nov 2018 14:57:45 +0100
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Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp> wrote:

> I had the following error with the following query.
>=20
> =3D# explain select * from pg_stat_get_activity(NULL) a join log(100000.0=
) p on a.pid =3D p.p;
> ERROR:  no relation entry for relid 2
>=20

I think that the problem is that RTE_VALUES is wrapped in a subquery by par=
ser
while RTE_FUNCTION is not. Thus some additional processing is done by
pull_up_simple_subquery() for VALUES. What seems to make difference here is
the call of flatten_join_alias_vars() on the query targetlist, although
pull_up_simple_subquery() does it for other reasons.

Actually the comment about flatten_join_alias_vars() in
pull_up_simple_subquery() makes me think if it's o.k. that
pull_up_simple_function() sets rvcontext.need_phvs=3Dfalse regardless stric=
tness
of the function: I think PlaceHolderVar might be needed if the function is =
not
strict. (In contrast, pull_up_simple_values() does not have to care because
pull_up_simple_subquery() handles such cases when it's processing the owning
subquery).

--=20
Antonin Houska
Cybertec Sch=C3=B6nig & Sch=C3=B6nig GmbH
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