Re: pgsql: Add per-index stats information in verbose logs of autovacuum

On Mon, Mar 22, 2021 at 10:36:03PM -0700, Peter Geoghegan wrote:
> It suggests that the index file can shrink. As if the remaining pages
> are left now that the pages we deleted have been returned to the OS. I
> think that this same line of output should look like this instead:
>
> index "dups_idx": 1431 pages in total, 1343 newly deleted,
> 1427 currently deleted, 84 reusable

I like the consistency of using "pages:" at the beginning of the line
as all those fields refer to pages, and your formulation makes inclear
what the second, third and fourth items on the line refer to. What's
newly-deleted? Tuples? Pages? Pages, obviously, if you know what
this is about.

> To be clear, I agree that it would not be sensible to make the
> log_autovacuum_min_duration output 100% consistent with VACUUM
> VERBOSE. I just think that "%u remain" is misleading. It's just that
> one detail.

Saying that, I like your suggestion of using "total" or "in total"
instead of "remain" for the first item.
--
Michael