Josh Berkus <josh@agliodbs.com> writes:
>>> "There were 33076 unused item pointers."
>>> Is this a count of dead index pointers, or something else?
>>
>> No, it's currently-unused item pointers (a/k/a line pointers) on heap
>> pages. See http://developer.postgresql.org/docs/postgres/page.html
> So this would be a count of pointers whose items had already been moved?
Either deleted, or moved to another page during VACUUM FULL compaction.
Such a pointer can be recycled to point to a new item, if there's room
to put another item on its page ... but if not, the pointer is
wasted space. I don't believe we ever try to physically eliminate
unused item pointers.
regards, tom lane