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From: Tender Wang <tndrwang@gmail.com>
Date: Wed, 25 Mar 2026 17:00:17 +0800
Message-ID: 
 <CAHewXN=Zzy7kPf3kSkxRzMY9tSZFOt8JRhKW_M_FzLY3px-esQ@mail.gmail.com>
Subject: Re: Fix "could not find memoization table entry"
To: David Rowley <dgrowleyml@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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David Rowley <dgrowleyml@gmail.com> =E4=BA=8E2026=E5=B9=B43=E6=9C=8825=E6=
=97=A5=E5=91=A8=E4=B8=89 10:09=E5=86=99=E9=81=93=EF=BC=9A
>
> On Wed, 25 Mar 2026 at 13:31, David Rowley <dgrowleyml@gmail.com> wrote:
> > Obviously, we don't want to back-patch anything that would cause a
> > user-visible change in the return value of hash_numeric(), so I've
> > been experimenting to see if there's any way to get PostgreSQL to
> > output any value from hash_numeric() larger than 2^31 and I've been
> > unable to. I tried:
>
> I was experimenting with a less risky fix by having the datum_image
> functions force the sign-extended representation of the Datum before
> hashing or comparing.
>
> Attached is a quick PoC of what that would look like. It does fix the
> reported problem. But it is a hack and doesn't fix the root cause of
> the issue.
>
> Despite the hackiness, I feel this might be better than the
> whack-a-mole approach of just fixing incorrect usages of the
> PG_RETURN_* macros as and when we find them.

No objection from me.
It seems no users have complained about hash_numberic(), and except
for this reported issue, no internal errors have been reported due to
hash_numberic().


--=20
Thanks,
Tender Wang