From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Cc: David Rowley <dgrowleyml@gmail.com>
Cc: sait.nisanci@microsoft.com, PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Subject: Re: BUG #17158: Distinct ROW fails with Postgres 14
Date: Tue, 31 Aug 2021 16:43:54 -0400
Message-ID: <2021952.1630442634@sss.pgh.pa.us> (raw)
In-Reply-To: <c182f5c8-fdf3-80a0-fa43-4ed7e87d4d47@enterprisedb.com>
References: <17158-8a2ba823982537a4@postgresql.org>
<CAApHDvp0w_5YY=7pxPkymtv7Oc0cGS=+jtiBvXrfcM6gLjT5Pg@mail.gmail.com>
<bc0ec85a-68cf-1b99-e80c-ee0c55b936db@enterprisedb.com>
<496046.1629843371@sss.pgh.pa.us>
<c182f5c8-fdf3-80a0-fa43-4ed7e87d4d47@enterprisedb.com>
Peter Eisentraut <peter.eisentraut@enterprisedb.com> writes:
> This feature is a requirement for multicolumn path and cycle tracking in
> recursive queries, as well as the search/cycle syntax built on top of
> that, so there is a bit more depending on it than might be at first
> apparent.
Hmm.
> Variant 1 is that we let the type cache *not* report hash support for
> the record type, and let callers fill it in. In the attached patch I've
> only done this for hash_array(), because that's what's needed to get the
> tests to pass, but similar code would be possible for row types, range
> types, etc.
> Variant 2 is that we let the type cache report hash support for the
> record type, like now, and then let callers override it if they have
> other options. This is the second attached patch.
I find variant 1 a bit cleaner, and safer. I'd rather default to
assuming that RECORD doesn't hash, when we don't have enough info
to be sure.
regards, tom lane
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Subject: Re: BUG #17158: Distinct ROW fails with Postgres 14
In-Reply-To: <2021952.1630442634@sss.pgh.pa.us>
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