"Shane Wright" <shane.wright@xxxxxxxxxxxxxxxxxxxx> writes: > If I change vacuum_mem I'll need to at least 'pg_ctl reload' - will it apply straightaway with the next vacuum query or does it need a full restart? reload is enough. > Basically if its just datfrozenxid that's not updated I can live with delaying the vacuum a few days. But if things are more serious then obviously I can't wait. The question is how close to the wraparound horizon is any of your data. We don't really know that --- the datfrozenxid provides a lower bound but we don't know where things are in reality. Also, are you prepared to tolerate wrong answers (missing rows) for awhile? As Martijn mentioned, the vacuum will retrieve rows that have slid past the wrap horizon, but they'll have been invisible to your queries meanwhile. regards, tom lane
