On 11/6/07, Mark Mielke <[EMAIL PROTECTED]> wrote: > 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.
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