Re: Visibility map thoughts

On Tue, 2007-11-06 at 13:29 +0000, Heikki Linnakangas wrote:

> > My list would be:
> > - EXISTS / NOT EXISTS
> > - COUNT(*)
> 
> Yeah, those are good candidates.

Yeah.

> Many-to-many relationships is one example:

OK, thats a very good one.

> And of course people will start adding columns to indexes, to make use 
> of index-only-scans, once we have the capability.

Not too keen on that. Very difficult to judge whether its worth the
benefit for creating lots of extra columns in indexes. Specifically,
this isn't going to speed up any existing application without additional
design work.

But seems like we have reasonable reason for them without that.

Do we know how much faster things might go if we do that?

--  Simon Riggs 2ndQuadrant  http://www.2ndQuadrant.com