Re: Bad performence using DESCENDING with index in ORACLE 7.3

From: <michael_bialik_at_my-deja.com>
Date: Thu, 23 Sep 1999 21:10:58 GMT
Message-ID: <7se50n$q6g$1@nnrp1.deja.com>

Hi.

The reverse pointers avaliable from Oracle 7.3, but as far as I know you have to use hint INDEX_DESC to enforce their usage by optimizer.
In Oracle 8i there is a possibility to create descending indexes as well as ascending.

Michael.

In article <37eafe10.2230557_at_88.0.3.103>, sh_ya_at_yahoo.com (Shaya) wrote:
> Hi All
>
> One of my customers is having performance problems trying to do a
> SELECT with a ORDER BY ... DESCENDING on an indexed column.
> I was once told that pirior to vertion 7.3 oracle had to read the
> index to a work area, sort it in decending order and than fetch the
> data, but from ver 7.3 this problem is solved, and the index had
> backward pointers that enable it to be read in reverse order.
> My customer said that when he asked, he was told that the problem is
> solved only from version 8.0.
>
> Can anyone solve this mystry for me?
> Is the reverse pointers available from version 7.3 or just from
> version 8.0?
>
> Thanks
>
> Shaya
>

Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't. Received on Thu Sep 23 1999 - 16:10:58 CDT