Laurenz Albe <laurenz.albe@xxxxxxxxxxx> writes: > It is not an incompatibility that warrants a mention in the release notes, > but perhaps somthing in > https://www.postgresql.org/docs/14/indexes-index-only-scans.html > and/or > https://www.postgresql.org/docs/14/routine-vacuuming.html#VACUUM-FOR-VISIBILITY-MAP > could be added that recommends that people should consider frequent > VACUUM with "index_cleanup = on" for best performance with index-only scans. If enough pages would change their all-visible state to make a significant difference in index-only scan performance, VACUUM should not be skipping the cleanup. If it is, the threshold for that is too aggressive. Assuming that that choice was made appropriately, I think the advice you propose here will just cause people to waste lots of cycles on VACUUM runs that have only marginal effects. regards, tom lane
