Message-ID: <3a173a9aba9650ce7ddf22af9c413a3d64debbf4.camel@cybertec.at>
Subject: Re: BUG #18523: String compare not consistent
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: patrick.van.dijk@gmail.com, pgsql-bugs@lists.postgresql.org
Date: Wed, 26 Jun 2024 17:59:24 +0200
In-Reply-To: <18523-d7b3cacb64d91cda@postgresql.org>
References: <18523-d7b3cacb64d91cda@postgresql.org>
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On Wed, 2024-06-26 at 09:43 +0000, PG Bug reporting form wrote:
> PostgreSQL version: 16.3
> Operating system:   Windows vs Linux/Azure
>=20
> When I try the following on a Azure/Linux version of PostgreSQL i see som=
e
> strange results that are not correct.
> On Windows the behavior is correct.
>=20
> select '|' < '0';		-- true, true, this is correct
> select '|1' < '01';	-- false, true, Azure/Linux is wrong
> select '||' < '0|';	-- true, true, this is correct
> select '||1' < '0|1';	-- false, true, Azure/Linux is wrong
>=20
> When the first character compares <, then no matter what follows, it shou=
ld
> be <...

That is certainly not a PostgreSQL bug, because PostgreSQL uses collations
defined by the C library (or the ICU library, if you use that).

So you'd have to complain to the authors of the respective library.

Interestingly, glibc and ICU disagree about that:

SELECT '|1' < '01' COLLATE "de_DE.utf8"  AS glibc,
       '|1' < '01' COLLATE "de-AT-x-icu" AS icu;

 glibc =E2=94=82 icu=20
=E2=95=90=E2=95=90=E2=95=90=E2=95=90=E2=95=90=E2=95=90=E2=95=90=E2=95=AA=E2=
=95=90=E2=95=90=E2=95=90=E2=95=90=E2=95=90
 f     =E2=94=82 t
(1 row)

Yours,
Laurenz Albe