From: Tom Lane <tgl@sss.pgh.pa.us>
To: Tomas Vondra <tomas.vondra@2ndquadrant.com>
cc: Andres Freund <andres@anarazel.de>, buschmann@nidsa.net,
        pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #16045: vacuum_db crash and illegal memory alloc after
 pg_upgrade from PG11 to PG12
In-reply-to: <20191013001032.lqrn4kqaovhrf77l@development>
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Comments: In-reply-to Tomas Vondra <tomas.vondra@2ndquadrant.com>
	message dated "Sun, 13 Oct 2019 02:10:32 +0200"
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Date: Sun, 13 Oct 2019 14:26:48 -0400
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Tomas Vondra <tomas.vondra@2ndquadrant.com> writes:
> here is an updated patch, with the recursive CTE. I've done a fair
> amount of testing on it on older versions (up to 9.4), and it seems to
> work just fine.

Might be a good idea to exclude attisdropped columns in the part of the
recursive query that's looking for sql_identifier columns of composite
types.  I'm not sure if composites can have dropped columns today,
but even if they can't it seems like a wise bit of future-proofing.
(We'll no doubt have occasion to use this logic again...)

Looks good other than that nit.

> BTW the query (including the RELKIND_COMPSITE_TYPE) was essentially just
> a lightly-massaged copy of old_9_6_check_for_unknown_data_type_usage, so
> that seems wrong too.

Yeah, we should back-port this logic into that check too, IMO.

			regards, tom lane