Re: should check collations when creating partitioned index

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Jeff Davis <pgsql(at)j-davis(dot)com>
Cc: Peter Eisentraut <peter(at)eisentraut(dot)org>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: should check collations when creating partitioned index
Date: 2023-11-17 20:18:57
Views: Raw Message | Whole Thread | Download mbox | Resend email
Lists: pgsql-hackers

Jeff Davis <pgsql(at)j-davis(dot)com> writes:
> In the patch, you check for an exact collation match. Considering this
> case only depends on equality, I think it would be correct if the
> requirement was that (a) both collations are deterministic; or (b) the
> collations match exactly.

You keep harping on this idea that we are only concerned with equality,
but I think you are wrong. We expect a btree index to provide ordering
not only equality, and this example definitely is a btree index.

Possibly, with a great deal more specificity added to the check, we
could distinguish the cases where ordering can't matter and allow
collation variance then. I do not see the value of that, especially
not when measured against the risk of introducing subtle bugs.

regards, tom lane

In response to


Browse pgsql-hackers by date

  From Date Subject
Next Message Tom Lane 2023-11-17 20:35:52 Re: Recovering from detoast-related catcache invalidations
Previous Message Andres Freund 2023-11-17 20:13:34 Re: simplehash: preserve consistency in case of OOM