public inbox for [email protected]  

help / color / mirror / Atom feed

From: Tom Lane <[email protected]>
To: Laurenz Albe <[email protected]>
Cc: Thomas Michael Engelke <[email protected]>
Cc: [email protected]
Subject: Re: ICU Collations and Collation Updates
Date: Mon, 14 Apr 2025 10:36:40 -0400
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
	<[email protected]>

Laurenz Albe <[email protected]> writes:
> On Mon, 2025-04-14 at 08:28 +0000, Thomas Michael Engelke wrote:
>> Is my understanding correct then in that this way the database
>> collations never change, unless a manual intervention reinitialises the
>> collations and reindexes the database (or appropriate indexes)? How
>> does that process compare to other RDBMS?

> When you update the C library or ICU library and the version changes,
> you get warned by PostgreSQL and have to rebuild indexes.
> So the collations can change whenever you update the respective libraries.
> You would have to build PostgreSQL yourself with a fixed version of ICU
> that you never upgrade if you want to avoid the problem.

Yeah.  AIUI there are two things that ICU does better than libc here:

1. ICU has a fairly well-defined scheme for identifying collation
versions, glibc not so much.  So the collation-changed warnings that
Laurenz mentions are a lot more trustworthy for ICU collations.

2. It's at least *possible* to use your own fixed-version ICU
library if you're desperate enough.  I don't think that would work
too well for libc; you're stuck with what the platform provides.

			regards, tom lane

view thread (3+ messages)

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: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected]
  Subject: Re: ICU Collations and Collation Updates
  In-Reply-To: <[email protected]>

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

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