Re: Multiple RBS tablespaces

In our last gripping episode gorgos_at_my-deja.com wrote:
> Hello again,
> a colleague of mine was suggesting that multiple rollback segment
> tablespaces was good. If the tablespaces are on seperate disks, I can
> understand that IO contention will be reduced, but if they're on the
> same disk and don't see the benefit. Am I missing the point here ??
>
> Thanks
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.
>

You very well could be. Multiple RBS tablespaces can be beneficial if it is necessary to configure transactional and batch rollback segments and the user population is large and active. Using the 8i feature of locally managed tablespaces it would then be possible to set up two RBS tablespaces with different storage parameters to accomodate transactional and batch rollback needs. If you're not on 8i you could still implement uniform extent sizing for both OLTP and batch transactions by having two RBS tablespaces. In this case the two tablespaces wouldn't need to be on separate disks since you're not likely to run batch transactions during the business day and the extent sizes for the two types of rollback segments wouldn't co-exist in the same tablespace thus opening the door to tablespace fragmentation.

On another front two RBS tablespaces could also be beneficial if the transaction load is high for the instance; in this case the two tablespaces would reside on separate disks and the segments would be created such that the odd-numbered segments are in one tablespace and the even-numbered segments in another thus alternating the tablespaces for subsequent rollback segment usage. This could provide the user community with faster rollback processing and access and increase the throughput to the database.

--
David Fitzjarrell
Oracle Certified DBA


Sent via Deja.com http://www.deja.com/
Before you buy.