Re: pctfree parameter for PK indexes based on running sequences.

nirav wrote:
> Hello Experts,
>
> We have around 400 primary key indexes,all are based on running
> sequences. The DDL that creates these sequences has pctfree of 10%.
> I recently read that pctfree is absolutely meaningless for indexes that
> are based on running sequences ...because it is meant to be there to
> allow for new inserts/updates etc , but in the case I refer, these
> updates will not be in existing nodes , they will allways be in the
> last leaf node ..So the conclusion is that for these indexes the
> pctfree of 0 could have saved us lots of space.
>
> I would be thankful if you can share your views on this.
>
> S.

Discussing PCTFREE and SEQUENCES in the same paragraph is as meaningful as discussing drain cleaners and WHERE clauses together.

PCTFREE in any primary key index should be set to 0 if the index is a true primary key. In your case, with surrogate primary keys, it should be 0 too. And it does matter unless you have some reason to think that reading vacuum makes sense.

-- 
Daniel A. Morgan
http://www.psoug.org
damorgan_at_x.washington.edu
(replace x with u to respond)