On Tue, May 24, 2005 at 08:36:36 -0700, mark durrant <markd89@yahoo.com> wrote: > > --MSSQL's ability to hit the index only and not having > to go to the table itself results in a _big_ > performance/efficiency gain. If someone who's in > development wants to pass this along, it would be a > nice addition to PostgreSQL sometime in the future. > I'd suspect that as well as making one query faster, > it would make everything else faster/more scalable as > the server load is so much less.
This gets brought up a lot. The problem is that the index doesn't include information about whether the current transaction can see the referenced row. Putting this information in the index will add significant overhead to every update and the opinion of the developers is that this would be a net loss overall.
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