Re: Use CASEFOLD() internally rather than LOWER()

On Sat, 2026-02-28 at 14:27 +0100, Daniel Verite wrote:
> I tried 0001 with a non-UTF8 database and got quickly stuck:

Attached new versions. I moved the encoding check into the SQL-callable
casefold() function, and other callers use str_casefold(). That
slightly simplifies what happens in ILIKE, also.

I removed the citext changes. citext has somewhat of a legacy status, I
think, so I'm not sure it makes sense to try to modernize or change it.
Also, some SQL-language functions in citext use LOWER(), so the changes
aren't enough: we'd need to make the SQL CASEFOLD function callable in
other encodings, and also run a citext upgrade script to change the
definitions.

Note that these changes affect the result of some expressions (e.g.
ILIKE), so could theoretically make an expression index or predicate
index inconsistent.

Regards,
    Jeff Davis