Re: When is a index unbalanced (blevel/no of records)

lars_v_andersen_at_hotmail.com (lars v. andersen) wrote in message news:<d6ea1901.0204020449.4f21ff32_at_posting.google.com>...
> Hi
>
> Could any one of you smart guys tell me if there is a rule of the
> thumb saying when an index is unbalanced and should be rebuilded.
>
> It must be able to express this with a relation between blevel and no
> of index entries.
>
> Best regards
> Lars V. Andersen

Indexes in Oracle are B+-trees hence they are NEVER unbalanced. They will degrade, but to my experience the best rule of thumb is to look at pct_used and del_lf_rows. As soon as PCT_USED falls below 70 percent it is time to rebuild, as the maximum in most cases is 90 percent.

Hth

Sybrand Bakker
Senior Oracle DBA Received on Tue Apr 02 2002 - 20:57:38 CEST