Re: POC: make mxidoff 64 bits

From: Heikki Linnakangas <hlinnaka(at)iki(dot)fi>
To: Ashutosh Bapat <ashutosh(dot)bapat(dot)oss(at)gmail(dot)com>, Maxim Orlov <orlovmg(at)gmail(dot)com>
Cc: Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>, Alexander Korotkov <aekorotkov(at)gmail(dot)com>, wenhui qiu <qiuwenhuifx(at)gmail(dot)com>, Postgres hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: POC: make mxidoff 64 bits
Date: 2025-12-03 19:12:40
Message-ID: ed232cb7-1fdc-415a-92e6-8df908ce6128@iki.fi
Views: Whole Thread | Raw Message | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

On 01/12/2025 14:35, Ashutosh Bapat wrote:
> On Mon, Dec 1, 2025 at 2:23 PM Maxim Orlov <orlovmg(at)gmail(dot)com> wrote:
>> On Fri, 28 Nov 2025 at 16:17, Ashutosh Bapat <ashutosh(dot)bapat(dot)oss(at)gmail(dot)com> wrote:
>>> An UPDATE waits for FOR SHARE query to finish, and vice versa. In my
>>> experiments I didn't see an UPDATE creating a multi-xact. Why do we
>>> have UPDATEs in the load created by the test? Am I missing something?
>>
>> As far as I remember, this was done on purpose to create different
>> multixact members statuses randomly.
>
> In that case, better to include that in the comments.

I think that was indeed the purpose, but the test should use FOR KEY
SHARE rather than FOR SHARE. Otherwise the UPDATEs don't generate multixids.

- Heikki

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Tomas Vondra 2025-12-03 19:23:39 Re: increased duration of stats_ext tests with -DCLOBBER_CACHE_ALWAYS
Previous Message Peter Eisentraut 2025-12-03 19:11:45 Re: Consistently use palloc_object() and palloc_array()