From: Jeff Davis <jdavis@postgresql.org>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: downcase_identifier(): use method table from locale provider.
Date: Tue, 16 Dec 2025 23:42:40 +0000
Message-ID: <E1vVegh-0019Bu-0g@gemulon.postgresql.org> (raw)
downcase_identifier(): use method table from locale provider.
Previously, libc's tolower() was always used for lowercasing
identifiers, regardless of the database locale (though only characters
beyond 127 in single-byte encodings were affected). Refactor to allow
each provider to supply its own implementation of identifier
downcasing.
For historical compatibility, when using a single-byte encoding, ICU
still relies on tolower().
One minor behavior change is that, before the database default locale
is initialized, it uses ASCII semantics to downcase the
identifiers. Previously, it would use the postmaster's LC_CTYPE
setting from the environment. While that could have some effect during
GUC processing, for example, it would have been fragile to rely on the
environment setting anyway. (Also, it only matters when the encoding
is single-byte.)
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/450ceb6260cad30d7afdf155d991a9caafee7c0d.camel@j-davis.com
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/87b2968df0f866aaccb6ba69adf284e3c4a79454
Modified Files
--------------
src/backend/parser/scansup.c | 36 +++++++++++--------------------
src/backend/utils/adt/pg_locale.c | 20 +++++++++++++++++
src/backend/utils/adt/pg_locale_builtin.c | 2 ++
src/backend/utils/adt/pg_locale_icu.c | 36 ++++++++++++++++++++++++++++++-
src/backend/utils/adt/pg_locale_libc.c | 33 ++++++++++++++++++++++++++++
src/include/utils/pg_locale.h | 5 +++++
6 files changed, 107 insertions(+), 25 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: jdavis@postgresql.org, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: downcase_identifier(): use method table from locale provider.
In-Reply-To: <E1vVegh-0019Bu-0g@gemulon.postgresql.org>
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