On Fri, 5 Apr 2002, Barry Lind wrote:
> Af far as I know Oracle doesn't have any short cut (along the lines of
> what is being discussed in this thread) for this operation. However
> Oracle is more efficient in providing the answer than postgres currently
> is. While postgres needs to perform a full scan on the table, Oracle
> will only need to perform a full index scan on the primary key if one
> exists. Since the index will likely have much less data than the full
Under Postgres, a full index scan is generally more expensive than a full
table scan since indices, particularly btree, carry a large amount of meta
data and theefore consume more pages.
Gavin