> On Sep 22, 2021, at 12:48 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> "David G. Johnston" <david.g.johnston@gmail.com> 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
accomplishedvia 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
settingsaren’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