Re: Incorrect Migrated/Chained rows...

Anna C. Dent wrote:

> What do you get if you do the following:
>
> create table temp_s_contact_03
> pctfree 15 pctused 80 inittrans 5 unrecoverable
> as (select * from s_contact
> where rowid in ( select head_rowid from chained_rows where table_name
> = 'S_CONTACT'));
>

What he'll get is a performance nightmare: the table is obviously subject to many updates, and you've just suggested setting pctfree and pctused so close together that blocks from this table are going to be bouncing on and off the freelist like no-one's business. (15% free = 85% full, therefore 85%-80% = merely a 5% gap between them).

I smell free list contention in the offing.

I agree with your 15 pctfree, but in that case he should set pctused to 35. That way, a 50% gap is maintained between the two settings... which is, after all, the default in any case (and hence, presumably, generally recommended).

Regards
HJR Received on Mon Apr 26 2004 - 22:37:29 CDT