On 2018-Aug-01, Andres Freund wrote: > On 2018-08-01 12:07:16 -0400, Tom Lane wrote: > > Andres Freund <andres@xxxxxxxxxxx> writes: > > > On 2018-08-01 10:24:24 -0400, Tom Lane wrote: > > >> IMO, the action you need to take is enabling autovacuum. We've > > >> seen many many people go down the path you are taking, and it's > > >> generally led to no good in the end. Manual vacuuming tends > > >> to miss stuff, and it cannot react adequately to activity spikes. > > > > > But it shouldn't matter here, autovacuum will start regardless, no? > > > > Sure, once it decides that emergency anti-wraparound vacuuming is > > necessary. I really doubt the OP wants that to happen; it's the > > exact opposite of non-intrusive. > > That's solely what would trigger it were autovacuum enabled, too? I've > complained about "emergency anti-wraparound" beeing anything but > emergency (they're largely unavoidable unless you manually script it), > but they're what happen once autovacuum_freeze_max_age is reached, and > that's the only trigger for vacuuming old relations independent of other > activity? With a small database like template0, it doesn't matter. The vacuuming is going to be over before OP realizes it has happened anyway. Certainly having it happen on a normal-sized table can become problematic, but presumably OP has taken steps to avoid it when disabling autovacuum (which is why only template0 is getting into trouble.) I think emergency vacuum should behave differently (not scan indexes, just apply HOT page prune and clear old XIDs/multixacts), which would make it much faster, but that's a separate line of thought (and of development). -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
