Re: Vacuum stats interpreted?

Jeff Boes <jboes@qtm.net> writes:
> The "Keep" and "UnUsed" numbers seem high to me, compared to other tables. Can
> anyone interpret these and tell me anything about what we could do with this
> table to make it "look" better?

"Keep" is the number of rows that are committed dead but had to be kept
anyway, because there are open transactions old enough to still
potentially see them.  The only way to reduce that is to not have old
transactions hanging 'round while you vacuum.

UnUsed is the number of empty line-pointer slots.  At 4 bytes apiece,
this would have to vastly exceed the number of live tuples before you
should worry much.

7.4 labels these numbers in a hopefully more user-friendly way, btw.

            regards, tom lane