Re: Is this Needed?

On 26/10/05, Freeman, Donald <dofreeman_at_state.pa.us> wrote:
> I just received a notice from our technical team leader that we were going to schedule a 'refresh' on our transactional database in order to improve performance. They are going to truncate and reimport the production schema. Is this technique useful for a 9i database? I'm thinking that in earlier versions of Oracle it might have been helpful but on the other hand I don't see any discussion of this on any board that I am monitoring. Is this a waste of time?

The only thing I can think of that that could do that might help performance (emphasis on might) is if you have a lot of migrated rows (rows that started out in one block and latrer moved to another block as a result of being updated) or a lot of deletions of indexed rows or updates of indexed fields resulting in lots of dead keys. As I recall from training, unless it's another myth taught as fact on courses, either of these could cause unnecessary physical IOs.

If you are having problems with migrated rows and dead keys then your time might be better spent on a a few 'alter table..move'/'alter index...rebuild' and trying to minimise reoccurances.

Stephen

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