Re: Minimally avoiding Transaction Wraparound in VLDBs

On Wed, 2005-08-31 at 22:21 -0400, Tom Lane wrote:
> Simon Riggs <simon@2ndquadrant.com> writes:
> > On Wed, 2005-08-31 at 19:24 -0400, Tom Lane wrote:
> >> If you don't remove any tuples,
> >> you don't scan the indexes anyway IIRC.
> 
> > No. Even if you remove *zero* tuples, an index is still scanned twice.
> > Once to not delete the rows and once to not delete the pages.
> 
> Yeah?  Well, that could probably be improved with a less intrusive fix,
> that is, one that does it automatically instead of involving the user.
> 
> I really really do not like proposals to introduce still another kind
> of VACUUM.  We have too many already; any casual glance through the
> archives will show that most PG users don't have a grip on when to use
> VACUUM FULL vs VACUUM.  Throwing in some more types will make that
> problem exponentially worse.

I'll post my proposal for changing that, so we can see the two
alternatives. I'm easy either way at the moment.

Best Regards, Simon Riggs