MIME-Version: 1.0
References: <CAFCRh-8NwJd0jq6P=R3qhHyqU7hw0BTor3W0SvUcii24et+zAw@mail.gmail.com>
 <CAFCRh-93hsRvoJqQCwXq06=AJJJ_s783gVsGHKc-QjgOO6jGVg@mail.gmail.com>
 <77a63548783dd4007ee479a4c5ed300629aaa776.camel@cybertec.at>
 <CAFCRh--DPWEHpRmdr-Jfw4guYqjc9TM_QyVH7SR4B=Le5gGe3Q@mail.gmail.com>
 <CAFCRh--M1y2YpJJMb6undzvyvhd4geKtRWFkDyr1shHvvoOkpQ@mail.gmail.com>
 <CAFCRh-_OBKtabe8MO0vUocNSq_O3_b852AXknPiNhL0tNUBGQg@mail.gmail.com>
 <CAFCRh-_U+8fmRoc-sYM5ahp=9dNjs=Dri1LFLcHCgEJX8Zq_oA@mail.gmail.com> <2109533.1757686026@sss.pgh.pa.us>
In-Reply-To: <2109533.1757686026@sss.pgh.pa.us>
From: Dominique Devienne <ddevienne@gmail.com>
Date: Fri, 12 Sep 2025 16:28:36 +0200
Message-ID: <CAFCRh-9YZpmWDE0grxDGuvNY04577fDZ=O0KvkQESE4QzgmoRg@mail.gmail.com>
Subject: Re: Latest patches break one of our unit-test, related to RLS
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Laurenz Albe <laurenz.albe@cybertec.at>, pgsql-general@postgresql.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Archived-At: <https://www.postgresql.org/message-id/CAFCRh-9YZpmWDE0grxDGuvNY04577fDZ%3DO0KvkQESE4QzgmoRg%40mail.gmail.com>
Precedence: bulk

On Fri, Sep 12, 2025 at 4:07=E2=80=AFPM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Dominique Devienne <ddevienne@gmail.com> writes:
> >> This DOES look like a bug, no? I've done regexes for a long time,
> >> and these two forms should be equivalent IMHO. --DD
>
> Yeah, I agree it's busted.  You can use EXPLAIN VERBOSE to see the
> translated-to-POSIX pattern, and it's wrong.

Thanks for confirming Tom.
And teaching me about that EXPLAIN VERBOSE trick.

I've worked-around that regression in our code, going to (x|y) instead.

What's weird is that those are still followed by _ and %,
just like [xy], so it's as-if seeing [\d\w], it stops converting
the pattern... Weird.

This misadventure kinda tells me I should maybe give up
on SIMILAR TO and just use ~, to bypass that conversion-to-POSIX...

--DD