Re: effective_multixact_freeze_max_age issue

On Mon, Aug 29, 2022 at 10:25:50AM -0700, Peter Geoghegan wrote:
> On Sun, Aug 28, 2022 at 4:14 PM Nathan Bossart <nathandbossart@gmail.com> wrote:
>> The idea seems sound to me, and IMO your patch simplifies things nicely,
>> which might be reason enough to proceed with it.
> 
> It is primarily a case of making things simpler. Why would it ever
> make sense to interpret age differently in the presence of a long
> running transaction, though only for the FreezeLimit/MultiXactCutoff
> cutoff calculation? And not for the closely related
> freeze_table_age/multixact_freeze_table_age calculation? It's hard to
> imagine that that was ever a deliberate choice.
> 
> vacuum_set_xid_limits() didn't contain the logic for determining if
> its caller's VACUUM should be an aggressive VACUUM until quite
> recently. Postgres 15 commit efa4a9462a put the logic for determining
> aggressiveness right next to the logic for determining FreezeLimit,
> which made the inconsistency much more noticeable. It is easy to
> believe that this was really just an oversight, all along.

Agreed.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com