On Wed, 2004-07-21 at 18:54, Rod Taylor wrote:
> > I don't know why the 1st VACUUM FULL wasn't able to reclaim the same
> > amount of space as the 2nd one, but I would guess that it wasn't able to
> > get a lock on some table. It could have been autovac if it was doing a
> > vacuum at that moment, but it could have been something else too.
>
> Or there was a long running transaction in the background. The oldest
> active transaction will place limits on what VACUUM can or cannot
> remove.
>
What happens when a transaction fails to either commit or abort as a
result of a serious error?
That looks like a transaction-in-progress doesn't it?
Would that prevent VACUUM from doing its work? It should be able to
check the last startup xid to check that isn't the case, but suppose a
backend had exited without taking down the postmaster.
(...waits for thunder...)
Best Regards, Simon Riggs