Re: Support regular expressions with nondeterministic collations

From: Jeff Davis <pgsql(at)j-davis(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Peter Eisentraut <peter(at)eisentraut(dot)org>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Support regular expressions with nondeterministic collations
Date: 2024-12-16 21:28:51
Message-ID: 024c9b9aa834f668496ef95700b57e50bf3f4808.camel@j-davis.com
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On Tue, 2024-10-22 at 10:40 -0400, Tom Lane wrote:
> I understand and agree with your conclusion
> that it's pretty much impossible to do what the SQL standard suggests
> should happen --- but maybe we're both missing something that would
> make it feasible.

It sounds feasible for case-insensitive collations, right? We just
casefold the pattern and the string, and then check for a match.

That's difficult given our current assumption that non-deterministic
collaitons can mean almost anything. But it's not necessarily a problem
with the standard, and perhaps some other systems do something like
that.

Regards,
Jeff Davis

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