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

Jeff Davis <pgsql@j-davis.com>

From: Jeff Davis <pgsql@j-davis.com>
To: Mark Dilger <mark.dilger@enterprisedb.com>
Cc: Daniel Verite <daniel@manitou-mail.org>, pgsql-hackers@postgresql.org
Date: 2026-03-24T23:07:51Z
Lists: pgsql-hackers
On Sat, 2026-03-21 at 20:14 -0700, Mark Dilger wrote:
> After v2-0001, ILIKE uses str_casefold() for matching, but pg_trgm
> still
> uses str_tolower() for trigram extraction (trgm_op.c:352 and :948).
> With builtin collations, these produce different results.

Interesting, thank you. As stated in the original message, I was unsure
about changing pg_trgm without adjusting the regex logic, also:

https://www.postgresql.org/message-id/64d7949bad90545f981ac7513fb0b4954daca2c9.camel@j-davis.com

do you have a suggestion about an easy way to do that, or should we
revisit in the next cycle?

Regards,
	Jeff Davis