Kevin Brown <kevin@sysexperts.com> writes:
> But as Tom pointed out, if you delete a bunch of data from a table
> then insert a fresh set of data, but don't end up inserting much data
> with roughly the same keys that were in the original batch of data,
> you'll get a lot of empty areas in your index that are unused. VACUUM
> marks them as being available for reuse, of course, but that doesn't
> help you unless you insert data containing values that are appropriate
> to the unused areas.
No, you misunderstood. That is the problem in existing releases --- but
in CVS tip, VACUUM can actually remove unused sections from the b-tree
and make that space available for re-use in other key ranges.
regards, tom lane
