From: Tom Lane <tgl@sss.pgh.pa.us>
To: Tomas Vondra <tomas@vondra.me>
cc: Sergey Belyashov <sergey.belyashov@gmail.com>,
        pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18815: Logical replication worker Segmentation fault
In-reply-to: <906545.1739821437@sss.pgh.pa.us>
References: <18815-2a0407cc7f40b327@postgresql.org>
 <832225.1739810351@sss.pgh.pa.us>
 <CAOe0RDwbowSGv8qeuqyHzJndtwV5JyPEG4YwmaAvgquC=gjz+Q@mail.gmail.com>
 <906545.1739821437@sss.pgh.pa.us>
Comments: In-reply-to Tom Lane <tgl@sss.pgh.pa.us>
	message dated "Mon, 17 Feb 2025 14:43:57 -0500"
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Date: Mon, 17 Feb 2025 15:13:00 -0500
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I wrote:
> I suspect that the attached will fix it.  What I don't understand
> is why it's apparently so hard to trigger the crash, because it
> looks to me like any two successive insert commands on the same
> BRIN index should hit this.

Oh, wait: I was confusing ii_AmCache with rd_amcache in the index's
relcache entry.  This coding would absolutely not work with rd_amcache
since that's persistent.  It mostly works with the IndexInfo field
though, since an IndexInfo typically only survives per-query.
Evidently there's some path in logical replication that will re-use an
IndexInfo across multiple distinct insertion operations, and that's
what breaks it.

> BTW, I'm also a bit suspicious of the comment's claim that the
> brinDesc doesn't need cleanup.  That looks like a potential
> memory leak.

This concern still stands.

			regards, tom lane