> I guess the overhead of one more scan of the process array for every autovacuum
> run if "log_autovacuum_min_duration" is non-zero (which is the default)
> is acceptable.
Could vacuum compute the blocker during ComputeXidHorizons and consume it at log time?
Avoids the extra scan, and binds the blocker to the horizon vacuum used for pruning.
Scott Ray