Re: pgsql: Improve autovacuum logging for aggressive andanti-wraparound ru

> On Sep 21, 2018, at 12:43 PM, Andres Freund <andres@anarazel.de> wrote:
> 
>> But as far i can see it is possible have aggressive non-wraparound vacuum. One important difference - regular and
aggressiveregular can be canceled by backend,.wraparound autovacuum can not. (by checking PROC_VACUUM_FOR_WRAPAROUND in
src/backend/storage/lmgr/proc.c)
 
> 
> Yes, without checking the code, they should be different. Aggressive is
> controlled by vacuum_freeze_table_age whereas anti-wrap is controlled by
> autovacuum_freeze_max_age (but also implies aggressive).

Right, except that by the time you get into the vacuum code itself nothing should really care about that difference.
AFAICT,the only thing is_wraparound is being used for is to set MyPgXact->vacuumFlags |= PROC_VACUUM_FOR_WRAPAROUND,
whichprevents the deadlock detector from killing an autovac process that’s trying to prevent a wraparound. I think it’d
beclearer to remove is_wraparound and move the check from vacuum_rel() into lazy_vacuum_rel() (which is where the
limitsfor HeapTupleSatisfiesVacuum get determined). Something like the attached.