Re: Rollback Segment Size

> From: Michael Alvarado <m_alvarado_at_VNET.IBM.COM>
> Subject: Rollback Segment Size
> X-To: oracle-l_at_ccvm.sunysb.edu
> To: Multiple recipients of list ORACLE-L <ORACLE-L_at_CCVM.SUNYSB.EDU>
> Status: RO
>
> I have a very transaction intensive database. Lots of inserts and updates
> from a large number of users. Is it better to have many small rollback segs
> or to have a few large ones for this configuration. (Oracle 7.1.6, RS/6000,
> AIX 3.2.5) Also, what is the optimal extent size and other parameters for
> the rollback segments in this case. (Aprox 150 concurrent users) Thanks
>

If your transactions are all small (which seems to be the case), create multiple RBSs of 500K Initial and 500K next. Optimal could be 5M. With 150 users, you could have 30 RBSs.

For large transactions, you could create a seperate RBS (5M + 1M) and keep it OFFLINE (by not including it in the init.ora file) normally. Bring it ONLINE when you want to use it and include "SET TRANSACTION USE ROLLBACK SEGMENT large" in your SQL.

Hemant Received on Fri Jan 26 1996 - 13:43:38 CST