Re: effective_multixact_freeze_max_age issue

Hello!

On 31.08.2022 21:38, Peter Geoghegan wrote:
> On Tue, Aug 30, 2022 at 8:56 PM Nathan Bossart <nathandbossart@gmail.com> wrote:
>> LGTM
> 
> Pushed, thanks.
> 

In this commit https://github.com/postgres/postgres/commit/c3ffa731a5f99c4361203015ce2219d209fea94c
there are checks if oldestXmin and oldestMxact havn't become too far in the past.
But the corresponding error messages say also some different things about 'cutoff for freezing tuples',
ie about checks for another variables: freezeLimit and multiXactCutoff.
See:
https://github.com/postgres/postgres/commit/c3ffa731a5f99c4361203015ce2219d209fea94c?diff=split#diff-795a3938e3bed9884d426bd010670fe505580732df7d7012fad9edeb9df54badR1075
and

https://github.com/postgres/postgres/commit/c3ffa731a5f99c4361203015ce2219d209fea94c?diff=split#diff-795a3938e3bed9884d426bd010670fe505580732df7d7012fad9edeb9df54badR1080

It's interesting that prior to this commit, checks were made for freeze limits, but the error messages were talking
aboutoldestXmin and oldestMxact.
 

Could you clarify this moment please? Would be very grateful.

As variant may be split these checks for the freeze cuttoffs and the oldest xmins for clarity?
The patch attached tries to do this.


-- 
Anton A. Melnikov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company