pg.ddx.io  pgsql-hackers@postgresql.org mailing list archive  

help / color / mirror / Atom feed
From: Jeff Davis <pgsql@j-davis.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Peter Eisentraut <peter@eisentraut.org>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@postgresql.org
Subject: Re: Remaining dependency on setlocale()
Date: Thu, 30 Oct 2025 10:17:03 -0700
Message-ID: <d78d6b0f539460d4d01a869b05fd487cd12cf6a3.camel@j-davis.com> (raw)
In-Reply-To: <d9657a6e51aa20702447bb2386b32fea6218670f.camel@j-davis.com>
References: <4c5da86af36a0d5e430eee3f60ce5e06f1b5cd34.camel@j-davis.com>
	<1841102.1722982989@sss.pgh.pa.us>
	<CA+hUKGK7qKDHgoh1HuvMhtcpAwwVBA5BDt33vCzYYqCLfQTtzw@mail.gmail.com>
	<CA+hUKGLLTy155HTQ6HfHu5-XPNfoFgDsRVUWevj+O6p3UmvPkg@mail.gmail.com>
	<a70d3db4b8291b61c6937c0c003aa70e2d2c3a9a.camel@j-davis.com>
	<CA+hUKGL82jG2PdgfQtwWG+_51TQ--6M9XNa3rtt7ub+S3Pmfsw@mail.gmail.com>
	<b19ea499a6d78c101dc55b61bfb42069b427445c.camel@j-davis.com>
	<fa04b56430fa4b5da7311c2faa113f406c6d192a.camel@j-davis.com>
	<CA+hUKGKcS-Zhi8Ud+tv2TanzXBQjH+WsLyPY9DUDXob5VoYAtg@mail.gmail.com>
	<cd3517c7-ddb8-454e-9dd5-70e3d84ff6a2@eisentraut.org>
	<d2e7d63c0cc98f425652527cf260a3e6da17d2b0.camel@j-davis.com>
	<a1396f17f462ee6561820f755caaf2d12eb9fd15.camel@j-davis.com>
	<9875f7f9-50f1-4b5d-86fc-ee8b03e8c162@eisentraut.org>
	<a8666c391dfcabe79868d95f7160eac533ace718.camel@j-davis.com>
	<6956823dd669abc64183fc91e64dc2e56e31f3ea.camel@j-davis.com>
	<ed394f839d813762ddcd65cfcab0e062f8b5e0b1.camel@j-davis.com>
	<CA+hUKGLYcbnHBXhHk_OFwZ03LE+D=cAirm7TVN8fMhT9rgcTbA@mail.gmail.com>
	<f040113cf384ada69558ec004a04a3ddb3e40a26.camel@j-davis.com>
	<CA+hUKGJxSDFcTZSGi++PTC=jM49q1oK=v7Lcdf96VQXXvLhoow@mail.gmail.com>
	<cdd20efc0f5418c597791a1e3a5abb68fa3ce35b.camel@j-davis.com>
	<d9657a6e51aa20702447bb2386b32fea6218670f.camel@j-davis.com>

On Tue, 2025-10-28 at 17:19 -0700, Jeff Davis wrote:
> Attached a new patch series, v6.

I'm eager to start committing this series so that we have plenty of
time to sort out any problems. I welcome feedback before or after
commit, and I can revert if necessary.

The goal here is to do a permanent:

   setlocale(LC_CTYPE, "C")

in the postmaster, and instead use _l() variants where necessary.

Forcing the global LC_CTYPE to C will avoid platform-specific nuances
spread throughout the code, and prevent new code from accidentally
depending on platform-specific libc behavior. Instead, libc ctype
behavior will only happen through a pg_locale_t object.

It also takes us a step closer to thread safety.

LC_COLLATE was already permenently set to "C" (5e6e42e4), and most of
LC_CTYPE behavior already uses a pg_locale_t object. This series is
about removing the last few places that rely on raw calls to
tolower()/toupper() (sometimes through pg_tolower()). Where there isn't
a pg_locale_t immediately available it uses the database default locale
(which might or might not be libc).

There's another thread for what to do about strerror_r[1], which
depends on LC_CTYPE for the encoding:

https://www.postgresql.org/message-id/90f176c5b85b9da26a3265b2630ece3552068566.camel@j-davis.com

pg_localeconv_r() does depend on the LC_CTYPE for the encoding, but it
already sets it from lc_monetary and lc_numeric, without using datctype
or the global setting. Then PGLC_localeconv() converts to the database
encoding, if necessary. So it's an exception to the rule that all ctype
behavior goes through a pg_locale_t, but it's not a problem. (Aside: we
could consider this approach as a narrower fix for strerror_r(), as
well.)

There may be a loose end around plperl, as well, but not sure if this
will make it any worse.

Some other LC_* settings still rely on setlocale(), which can be
considered separately unless there's some interaction that I missed.

Note that the datcollate and datctype fields are already mostly
irrelevant for non-libc providers. We could set those to NULL, but for
now I don't intend to do that.

Regards,
	Jeff Davis






view thread (96+ messages)  latest in thread

Message-ID: <d78d6b0f539460d4d01a869b05fd487cd12cf6a3.camel@j-davis.com>
Permalink:  ../d78d6b0f539460d4d01a869b05fd487cd12cf6a3.camel@j-davis.com/
Also on:    postgresql.org/message-id/d78d6b0f539460d4d01a869b05fd487cd12cf6a3.camel@j-davis.com

 · 

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-hackers@postgresql.org
  Cc: pgsql@j-davis.com, thomas.munro@gmail.com, peter@eisentraut.org, tgl@sss.pgh.pa.us
  Subject: Re: Remaining dependency on setlocale()
  In-Reply-To: <d78d6b0f539460d4d01a869b05fd487cd12cf6a3.camel@j-davis.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox