Re: Skipping VACUUM of indexes when no work required

On Wed, 2005-12-07 at 09:55 -0500, Tom Lane wrote:
> Simon Riggs <simon@2ndquadrant.com> writes:
> > We discussed an optimization of VACUUM here
> > http://archives.postgresql.org/pgsql-hackers/2005-09/msg00046.php
> > that would allow VACUUM to complete faster by avoiding scanning the
> > indexes when no rows were removed from the heap by the VACUUM.
>
> Unfortunately I can't read that message right now because archives
> isn't responding, but this seems like a pretty bad idea to me.
> You still have to do the vacuum cleanup pass (at least in the btree
> case, and the only reason gist doesn't need it is it's not yet up
> to speed) so there's no real savings.

There are real savings; this is not a theoretical patch.

One pass of an index is faster than two, always.

Best Regards, Simon Riggs