Re: Optimal Setting

Phil Cook wrote:
>
> What is the consensus on the optimal rollback setting ; I have heard
> a number of different figures ; 3, 10, 20 * the initial extent.
>
> Thanks In Advance
>
> Phil Cook

The recommended configuration is to make your initial and next extents the size of a "typical" transaction. You should have one rollback segment for every ten active transactions. For performance reasons, you should then have twenty extents (minextents) per rollback segment. If you have sized the rollback segments properly, then optimal should be the same size as the original size of the rollback segments, which would therefore be (20 * initial). [With next = initial]

The trick is to make the rollback segments large enough to accomodate the "typical" transactions without the expense of dynamic allocation of extents, but small enough that you can cache as much of the rollback segments in the database buffer cache as possible. Received on Tue Sep 16 1997 - 00:00:00 CDT