Re: Rollback segment/tablespace growth problem

I guess you have more than one rollback segment in your RBS tablespace, and you haven't set OPTIMAL for any of them. This will cause the tablespace to fill up even when your actual data is not that big. Imagine you have 4 rollback segments r01, r02, r03 and r04 in the tablespace RBS, each of these rollback segments being 10MB at the beginning and the total tablespace size is 100MB. The free space left on RBS is 60 MB (100 - (10+10+10+10)). Let's say you modified a 50MB table and this transcation was held by rollback segment r01. Now r01 has grown to 50MB. Now the free space is 20MB (100 - (50+10+10+10)). Now if on a later date you modified the 50MB table again, and the transaction was held by r02. Now, r02 has to grow to 50MB to accomodate the whole modified table. But there isn't enough space in the RBS tablespace for this. The r01 rollback segment keeps occupying the space even when it is not used.

To get rid of this problem, you need to specify the OPTIMAL setting for the rollback segment to allow them to shrink automatically, or you have to shrink them manually.

Hope this helps. Received on Fri Sep 28 2001 - 11:24:44 CDT