On Mon, Jun 28, 2021 at 08:51:50AM -0400, Andrew Dunstan wrote: > On 6/28/21 2:39 AM, Peter Geoghegan wrote: > > I agree that in practice that's often fine. But my point is that there > > is another very good reason to not increase autovacuum_freeze_max_age, > > contrary to what the docs say (actually there is a far better reason > > than truncating clog). Namely, increasing it will generally increase > > the risk of VACUUM not finishing in time.
Yep, that doc section's priorities are out of date. > But if you're really worried about people setting > autovacuum_freeze_max_age too high, then maybe we should be talking > about capping it at a lower level rather than adjusting the docs that > most users don't read. If a GUC minimum or maximum feels like a mainstream choice, it's probably too strict. Hence, I think the current maximum is fine. At 93% of the XID space, it's not risk-averse, but it's not absurd.
