Re: Oracle instructor said...

Hi Bob,

In general:
For normal transactions, create a high number a small segments, it's better for caching reasons. Have ONE BIG rollback segment for special long-running jobs, with few big extents (3,4) (one extent could be 50 or 100Mb each)..

Normally, Minextents could be equal to 2, but it's not a bad idea to set it to 20.
Be careful with OPTIMAL, you should put it to 20 times INITIAL. It's not good to set OPTIMAL too low, because if there are long-running jobs you could have the error "SNAPSHOT TOO OLD" !

MaxEXTENTS should be set to a value slightly less than maximum allowed (max=121 extents if your block size=2K then let's say 110), so If you reach that limit you know you have a problem but you can still face the situation and manually alter the NEXT parameter. If you want to trap fragmentation problem before, set it to less than 110 (50 is a reasonable limit?). BUT DEFINITELY NOT 2 Jeff (jgrimons_at_pt.lu)

Bob Yeh <Bob_Yeh_at_vaffx2_at_cscuuxch.dayton.csc.com> wrote in article <3308B39E.4CAF_at_cscuuxch.dayton.csc.com>...
> Hi,
>
> I attended an Oracle training last week. The instructor told us to set
> the initial extent and next extent for rollback segs 10% larger than the
> largest table in the database. Also set the min/max extents to 2 ONLY.
> This way no expanding/shrinking will take place.
>
> Is this a good practice? How come no other tuning book recommend this
> way.
>
> Thanks.
> Bob
>
  Received on Sat Feb 22 1997 - 00:00:00 CST