Doubt w.r.t vacuum

Hi,

I was just wondering over it. This is for difference between vacuum full and 
vacuum analyze. Can somebody enlighten,

1. IIRC vacuum recovers/reuses dead tuples generated from update but can not do 
so for delete? Why?

2. Vacuum full locks entire table, is it possible that it locks a page at a 
time and deal with it. It will make vacuum full non-blocking at the cost of 
letting it run for a longer time. Or is it that the defragmentation algorithm 
needs more than a page?

Just a thought..


ByeShridhar

--
Weed's Axiom:    Never ask two questions in a business letter.    The reply will 
discuss the one in which you are    least interested and say nothing about the 
other.