| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> |
| Cc: | Peter Geoghegan <pg(at)bowt(dot)ie>, "Daniel Westermann (DWE)" <daniel(dot)westermann(at)dbi-services(dot)com>, "pgsql-generallists(dot)postgresql(dot)org" <pgsql-general(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Behavior change in PostgreSQL 14Beta3 or bug? |
| Date: | 2021-09-06 15:59:49 |
| Message-ID: | 3065647.1630943989@sss.pgh.pa.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general |
Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> 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
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Laurenz Albe | 2021-09-06 16:21:13 | Re: Behavior change in PostgreSQL 14Beta3 or bug? |
| Previous Message | Laurenz Albe | 2021-09-06 15:48:42 | Re: Behavior change in PostgreSQL 14Beta3 or bug? |