I've been following this discussion and would like to add my
2 cents.
> Unless I'm missing something major, that's completely bonkers. It
> might be true that it would be a good idea to vacuum such a table more
> often than we do at present, but there's no shot that we want to do it
> that much more often.
This is really an important point.
Too small of a threshold and a/v will constantly be vacuuming a fairly large
and busy table with many indexes.
If the threshold is large, say 100 or 200 million, I question if you want autovacuum
to be doing the work of cleanup here? That long of a period without a autovacuum
on a table means there maybe something misconfigured in your autovacuum settings.
At that point aren't you just better off performing a manual vacuum and
taking advantage of parallel index scans?
Regards,
Sami Imseih
Amazon Web Services (AWS)