Re: odd number of rollback segments

Nick Keighley wrote:
> Hi,
>
> I gather questions about Rollback Segments are quite common...
>
> I'm running Oracle 8, and no I'm not going to be able to upgrade soon.
>
> My system seems to be using a lot of disc space with ARC files. It's
> generating
> about 10 ARC files /min. I understand this is Bad and may indicates
> too few
> (or too small) rollback segments. Today I got an ORA-01555 for slowish
> transaction.
> Again this is probably related to RBSs.
>
> Only two public rbs appear to be specifically created by the startup
> SQL.
> So presumably Oracle created the rest. There are 7 (RBS0-RBS6).
>
> I've dug back though various configuration parameters
>
> processes=50 (sounds big for my environment)
> sessions=60
> transactions=66
> transactions_per_rollback_buffer=5 (TPR)
>
> hence Oracle should allocate transactions/TPR=13.2 public RBS
> and not a measly 7. Why?
>
> What do I have to do to change the number of processes? Update the
> init.ora
> and restart the database?
>
> My rollback segments are all 2M except for number 6 which is 4M. Why?

eek! I have now found the file that is really building the database. It creates
7 RBS...

-- 
Nick Keighley