Re: MVCC and index-only read

On Tue, Nov 18, 2008 at 2:33 PM, Thomas Kellerer <spam_eater@gmx.net> wrote:
> If all the columns from the select list are available in the index, then
> Oracle will always prefer the index scan over a table scan (at least I have
> never seen something else). Even for a SELECT that returns all rows of the
> table.

No, it doesn't always prefer index fast full scan.

> They are taking this concept even further with index organized tables, where
> no real "table data" exists, everything is stored in the index (quited nice
> for e.g. link tables that only consist of two or three integer columns)

Those are essentially clustered indexes, and they're not quite stored
exactly the same..

--
Jonah H. Harris, Senior DBA
myYearbook.com