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In-Reply-To: 
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From: Etsuro Fujita <etsuro.fujita@gmail.com>
Date: Fri, 19 Jun 2026 21:30:02 +0900
Message-ID: 
 <CAPmGK16O3B8v=TH3HqSV3X6E2_XySbFN8DVjKNXqQ7rdSMgh5A@mail.gmail.com>
Subject: Re: use of SPI by postgresImportForeignStatistics
To: Corey Huinker <corey.huinker@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>,
	"pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
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On Fri, Jun 19, 2026 at 6:23=E2=80=AFAM Corey Huinker <corey.huinker@gmail.=
com> wrote:
> Attached are two patches to remove SPI from the postgres_fdw.c, replaced =
by local C functions.  The division into two patches is entirely for readab=
ility. Separately, each one represents a half-measure that would benefit no=
 one. The first does the minimal changes needed to get the relation-stats t=
o stop using SPI, and the second does the same for attribute stats, removes=
 all vestiges of SPI from postgres_fdw.c, and adds some tests to make sure =
that a foreign table has the exact stats of the source loopback table.
>
> The function import_attribute_stats() is a bit parameter-happy, but that'=
s mostly necessary. I left the non-key parameters as all type char* because=
 that avoids even more "bool foo_isnull" parameters, and that allows the ca=
ller to not have to rework the various stat types into their corresponding =
C types (float, int4, float[], and the anyarrays that basically aren't cast=
-able by any client program anyway). I'm open to requiring the caller to us=
e the right datatypes for some of the parameters, but as I said there is no=
 way to "win" with the anyarrays, and even the pg_restore_attribute_stats()=
 function falls back to type text for those.
>
> To be clear, this solves the SPI problem, but questions about the design =
of attribute_statistics_update() and relation_statistics_update() remain, b=
ut those concerns are now isolated within their respective files attribute_=
stats.c and relation_stats.c. The inefficiencies therein aren't really in a=
 critical path, so if we wanted to leave them be until v20 they could, but =
if time allows I'd at least like try unwinding some of that. But first, let=
's get SPI out of postgres_fdw.c.

Ok, I'll review the patches.

Thanks!

Best regards,
Etsuro Fujita