On Fri, 24 Apr 2026 at 01:04, Mok <[email protected]> wrote: > > On Thursday, April 23rd, 2026 at 4:44 AM, David Rowley <[email protected]> > wrote: > > > On Thu, 23 Apr 2026 at 08:19, Mok <[email protected]> wrote: > > > For example, set to 0.8 a 'standard' vacuum would be triggered when the > > > table reached 160million with a default 200million setting. > > > > If that's what you want, why wouldn't you set the > > autovacuum_freeze_max_age to 160million? > > Because that would trigger a 'to-prevent-wraparound' vacuum, which is what > this change is trying to avoid.
Yes, it would. Why do you want to prevent them? I believe a few people have been alarmed in the past about the "to prevent wraparound" text in pg_stat_activity or when they saw those words in the logs. The default 200 million autovacuum_freeze_max_age setting triggers an autovacuum when it's less than 10% of the way into exhausting the transaction space for the table. What you're proposing with an autovacuum_age_scale_factor of 0.1 sounds like it would result in an auto-vacuum when only 1% of the transaction ID space is consumed! I think you're under the false impression that these anti-wraparound vacuums are bad. They're not. There's some documentation that might be worthwhile reading in [1]. David [1] https://www.postgresql.org/docs/18/routine-vacuuming.html#VACUUM-FOR-WRAPAROUND
