From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alexander Korotkov <aekorotkov@gmail.com>
cc: Tender Wang <tndrwang@gmail.com>, nicolas.maus@bertelsmann.de,
        pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18692: Segmentation fault when extending a varchar column
 with a gist index with custom signal length
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Comments: In-reply-to Alexander Korotkov <aekorotkov@gmail.com>
	message dated "Fri, 08 Nov 2024 01:28:06 +0200"
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Date: Thu, 07 Nov 2024 21:05:48 -0500
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Alexander Korotkov <aekorotkov@gmail.com> writes:
> On Thu, Nov 7, 2024 at 8:47=E2=80=AFAM Tender Wang <tndrwang@gmail.com> =
wrote:
>> Based on Tom's analysis, I  provide a POC patch. I'm not sure if it is =
right
>> to use DEFAULT_COLLATION_OID in the patch.

> Thank you.  But I'm not sure about DEFAULT_COLLATION_OID.

I don't quite trust that either.  But since we only care about
equality, wouldn't it be OK to use C_COLLATION_OID?

> Therefore, we can compare two text[] just with datumIsEqual().
> Attached patch implements this.

I think this is nonsense.  What about toasted datums, or even
just short-header ones?  The one coming from an on-disk tuple
is pretty likely to be short-header for plausible sizes of
the options, but the one we just constructed in memory will
not be.

			regards, tom lane