From: Tom Lane <tgl@sss.pgh.pa.us>
To: David Rowley <dgrowleyml@gmail.com>
Cc: sait.nisanci@microsoft.com, PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Cc: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Subject: Re: BUG #17158: Distinct ROW fails with Postgres 14
Date: Tue, 24 Aug 2021 10:03:26 -0400
Message-ID: <333555.1629813806@sss.pgh.pa.us> (raw)
In-Reply-To: <CAApHDvp0w_5YY=7pxPkymtv7Oc0cGS=+jtiBvXrfcM6gLjT5Pg@mail.gmail.com>
References: <17158-8a2ba823982537a4@postgresql.org>
<CAApHDvp0w_5YY=7pxPkymtv7Oc0cGS=+jtiBvXrfcM6gLjT5Pg@mail.gmail.com>
David Rowley <dgrowleyml@gmail.com> writes:
> It looks like 01e658fa74 is to blame for this.
> The test case can be simplified down to just:
> create table local (b bit);
> insert into local values('1'),('0');
> SELECT DISTINCT ROW(b) FROM local;
> Tom did have a look at this and raise the question about the
> possibility of not being able to hash in [1].
Huh. According to the thread, we discussed this exact possibility and
there's a test case verifying it ... so apparently something got
fat-fingered there.
> If it's going to be a problem detecting the lack of hashability during
> planning then maybe we can just add a hash opclass for BIT to fix this
> particular case.
Most certainly not. That would translate to a requirement that EVERY
data type have a hash function.
regards, tom lane
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Cc: tgl@sss.pgh.pa.us, dgrowleyml@gmail.com, pgsql-bugs@lists.postgresql.org, peter.eisentraut@enterprisedb.com
Subject: Re: BUG #17158: Distinct ROW fails with Postgres 14
In-Reply-To: <333555.1629813806@sss.pgh.pa.us>
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