Re: 10gR1 new feature: "Enhanced Bitmap Index Performance"

On Mar 16, 7:55 am, "Jonathan Lewis" <jonat..._at_jlcomp.demon.co.uk> wrote:
> One of the points on the following blog entry answers your
> question. The index does not acquire a huge trail of "old"
> blocks as it used to with small updates before 10g.
>
> http://jonathanlewis.wordpress.com/2006/12/19/mything-in-action/
>
> --
> Regards
>
> Jonathan Lewis

Thanks Jonathan.

Another statement that puzzles me (http://download-west.oracle.com/ docs/cd/B10501_01/server.920/a96533/data_acc.htm#2432) "Index maintenance is deferred until the end of each DML operation. ... For example, when you insert 1000 rows, the inserted rows are placed into a sort buffer and then the updates of all 1000 index entries are batched. (This is why SORT_AREA_SIZE must be set properly for good performance with inserts and updates on bitmap indexes.) Thus, each bitmap segment is updated only once in each DML operation, even if more than one row in that segment changes."

Does this mean that there is no reason at all to set my BMIs to unusable and rebuild them afterwards, if I am using bulk operations? (Bulk meaning direct path inserts and/or?? forall based pl/sql bulk inserts?)

Regards, Erik Received on Fri Mar 16 2007 - 07:59:29 CDT