Re: [PATCH] Fix null pointer dereference in PG19

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Paul A Jungwirth <pj@illuminatedcomputing.com>
Cc: Peter Eisentraut <peter@eisentraut.org>, Aleksander Alekseev <aleksander@tigerdata.com>, PostgreSQL Development <pgsql-hackers@postgresql.org>
Date: 2026-07-08T02:07:37Z
Lists: pgsql-hackers
Paul A Jungwirth <pj@illuminatedcomputing.com> writes:
> On Tue, Apr 21, 2026 at 8:24 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Checking this at parse time is completely the wrong thing.
>> The view could have gained (or lost) triggers by the time
>> it's executed.

> But INSTEAD OF triggers are selected in the rewriter, which uses the
> same relcache snapshot as parse analysis. And a concurrent change
> can't sneak in different triggers, because that causes a relcache
> invalidation, so we redo the parse & rewrite phases.

You have forgotten about views and rewrite rules.  Those go to disk in
post-parser form, and will be rewritten only at execution sometime
later, *without* a re-parse.

			regards, tom lane