> On Sep 22, 2021, at 12:48 PM, Tom Lane <tgl@xxxxxxxxxxxxx> wrote: > > "David G. Johnston" <david.g.johnston@xxxxxxxxx> writes: >> There is no where clause so I'm doubtful there is much to be gained going >> down this path. The Index-Only scan seems like an optimal way to obtain >> this data and the existing query already does that. > > The "index-only" scan is reported to do 86m heap fetches along the > way to returning 812m rows, so the data is apparently pretty dirty. > It's possible that a preliminary VACUUM to get page-all-visible hint > bits set would be a net win. I do have autovaccum turned on, but perhaps I need to do a manual? The initial population of the database was accomplished via logical replication from a different database cluster (needed to move this database to more dedicated hardware), so perhaps that left the database in a state that autovaccum doesn’t address? Or perhaps my autovaccum settings aren’t kosher - I haven’t adjusted that portion of the config any. --- Israel Brewster Software Engineer Alaska Volcano Observatory Geophysical Institute - UAF 2156 Koyukuk Drive Fairbanks AK 99775-7320 Work: 907-474-5172 cell: 907-328-9145 > > regards, tom lane
