Re: More Praise for 7.4RC2

On Thu, 2003-11-13 at 13:10, scott.marlowe wrote:

> So, if your table is HIGHLY updated, you may need to run a plain vacuum
> very often, and that's where the autovacuum daemon comes in handy. Just
> set it to run every 30 minutes or so, and let it go. It should only
> vacuum the tables that have had lots of change, and leave the others
> alone.

On Thu, 2003-11-13 at 19:37, Greg Stark wrote:

> However on a big heavily used database where the fsm parameters haven't been
> raised from the defaults it's possible that it isn't. And on a table where
> large batch updates or deletes have been run it's possible to require a vacuum
> full after the batch job creates lots of dead tuples.

Scott & Greg-

Thanks for this info. I'm sure this explains at least part of the
problem. I can't remember the sequence of events from several months
back, but I did once update ~20M rows of this 40M row this table, and I
have also deleted certain sets of rows at various times. Suspecting that
I had a swiss-cheese table, I reclustered on an index several times
(which, I presume, is at least as good as vacuum (non-full) removing
internal free space, with the benefit of optimized row ordering). Since
I can't remember the order of operations, it's possible that I timed the
slow query at nearly the worst state, and it's the kinda think I only
wanted to endure once.

Thanks again,
Reece

--
Reece Hart, http://www.in-machina.com/~reece/, GPG:0x25EC91A0