Simon Riggs wrote:
> On Mon, 2007-11-05 at 09:52 +0000, Heikki Linnakangas wrote:
> I'm racking my brain trying to think of a query that will benefit from
> index-only scans without specifically creating covered indexes. Apart
> from count(*) queries and RI lookups. I can't see RI lookups being much
> cheaper with this technique, do you see something there
I'm not sure what RI lookup is. Sorry. :-)
My list would be:
- EXISTS / NOT EXISTS
- COUNT(*)
- Tables that are heavily updated - any case where the index entry often
maps to a non-visible tuple.
Beyond that, yeah, I cannot think of other benefits.
Cheers,
mark
--
Mark Mielke <mark@mielke.cc>
