Message-ID: <7009dd30-5d4e-49a2-af1d-c1b5f8e02288@postgrespro.ru>
Date: Thu, 27 Nov 2025 12:39:34 +0400
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Subject: Re: Partial hash index is not used for implied qual.
To: David Rowley <dgrowleyml@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@lists.postgresql.org
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From: Sergei Glukhov <s.glukhov@postgrespro.ru>
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Hi,

On 11/27/25 7:01 AM, David Rowley wrote:
> On Thu, 27 Nov 2025 at 07:26, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> So I'm inclined to apply the attached and just call it good.
> I think the patch looks fine.

+1, verified, thanks a lot!

>
>> Should we back-patch?  I'm unsure.  Clearly it's a bug that we
>> cannot generate an indexscan plan in this case, but we've learned
>> that changing plans in released branches is often not wanted.
>> And given the lack of field complaints, nobody is using the case
>> anyway.
> I feel like anyone adding a partial hash index has done so quite
> purposefully. I suspect they might be surprised if there's no means
> whatsoever to use that index in scans, so perhaps it's ok to
> backpatch.
>
> Sergei, can you confirm if this was something he noticed when playing
> around on master, or if this came from a field report?

It was reported for v16.


Regards,
Sergei Glukhov