Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> c.d.o.server -> Re: Performance Issue

Re: Performance Issue

From: Eric Junkermann <eric_at_deptj.demon.co.uk>
Date: Sat, 12 Sep 1998 16:41:53 GMT
Message-ID: <35f8f6bc.611291235@news.demon.co.uk>


On Fri, 04 Sep 1998 03:03:33 GMT, sooz_at_pobox.com (Susan) wrote:

>Unique indexes ultimately take longer when massive updates are being
>done, because they need to check the entire index for a non-match
>before the record can be commited, else they error. On extremely
>large tables, that might make a difference.
>

<snip>

Sorry, but Oracle indexes are B-trees, so the insert algorithm can't help detecting a duplicate, since when it arrives at the insertion point for the new value, it's either already there (give up) or not (put it in). Non-unique indexes are exactly the same, except that there's never any point in giving up, and the new value is always inserted.

Eric. Received on Sat Sep 12 1998 - 11:41:53 CDT

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US