Re: RRN in SQL and Full table scan...

On Thu, Jul 28, 2016 at 11:09 AM, Birgitta Hauser <Hauser@xxxxxxxxxxxxxxx>
wrote:

1. What happens if you add an Order By to your SELECT statement with the
range?

​Still a full table scan​

2. What happens if you additionally create a derived index over the
relative record no?

​A full table scan w/o ORDER BY, Index probe with ORDER BY, returning in
61ms.


Interestingly, the "estimated number of rows" coming out of the table scan
is 745,428.​


​Which is then feed into an "AND" operation...with 745,429 rows coming out
of that into the final select.

I tried adding an OPTIMIZE FOR 11 ROWS, that didn't have an effect.

Also tried FETCH FIRST 11 ROWS ONLY..​that still shows the table scan with
745,428 rows, but it returns in 241ms instead of 27.4s

Charles