Re: Free-space-map management thoughts

Robert Treat <xzilla@users.sourceforge.net> writes:
> Now that indexes are getting some reporting, my understanding is an
> index would report fewer pages overall than it's associated table, but
> those pages would be completely empty.  However, given that they don't
> reported non-empty pages, the percentage of freeable space to total
> space would be unfairly lower (if I'm right in thinking that the back
> end will assume that non-reported pages don't have empty space in them).
> This would tend to hurt index management even though it's pages are the
> best candidates for removal (100% empty). Is this a valid concern, or am
> I misreading something?

I'm not following your point... across relations, the proposed scheme
only considers numbers of pages, not how much space is believed free in
each such page.  If anything I suspect it would over-favor the indexes.
        regards, tom lane