Re: BUG #17158: Distinct ROW fails with Postgres 14 - Mailing list pgsql-bugs

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