Re: another autovacuum scheduling thread

> Here's an updated patch with new GUCs that control how much each component
> contributes to the autovacuum score for a table. They default to 1.0, but
> can be set anywhere from 0.0 to 1.0 (inclusive). In theory, setting all of
> them to 0.0 should restore the original pg_class order prioritization that
> we have today. I haven't added corresponding reloptions for these GUCs, as
> I'm not convinced we need them, but I can add them if folks think they
> would be useful.

Starting with GUCs is OK by me.

Just a few things:

1/
+ Oid xid_age;
+ Oid mxid_age;

Is using Oid here intentional? I'm curious why not use uint32 for clarity?

2/
The new GUC docs says "...component of the score...", but without
introducing the concept of the prioritization score.
I think we should expand a bit more on this topic to help a user
understand and tune these more effectively. Attached is my
proposal for the docs. I tried to keep it informative without
being too verbose, and avoided making specific recommendations.

--
Sami Imseih
Amazon Web Services (AWS)