Re: TRANSACTIONS_PER_ROLLBACK_SEGMENT (the real story)

The real story may be higly misleading...

If you have public rollback segments this parameter will determine (based on the number of processes in init<sid>.ora) how many rollback segments are brought online.
This is, AFAIK, a one-time operation, rollback segments are not added dynamically.
Hundred segments is outrageous. Oracle has the 'rule of four' which means one rollback segment for every four users, with a minumum of four rollback segments.

Hth,

--
Sybrand Bakker, Oracle DBA
john v <johnvue_at_gte.net> wrote in message news:sh137sg3nk47lqqk4l3cr7gie6ev5rgnuf_at_4ax.com...
> Can the init.ora parameter "TRANSACTIONS_PER_ROLLBACK_SEGMENT"
> really affect how Oracle distributes its rollback activity during live
> use?
>
> I'm aware of the N=TRANSACTIONS/TRANSACTIONS_PER_ROLLBACK_SEGMENT
> which sounds like the minimum Oracle tries TO BRING ONLINE... but the
> documentation is not clear on whether
> TRANSACTIONS_PER_ROLLBACK_SEGMENT affects anything after Oracle is
> already up.
>
> I have a system where Oracle unevenly directs many transactions to 2
> segments out of 100. This is not due to ALTER SESSION SET
> TRANSACTION. I was hoping that reducing
> TRANSACTIONS_PER_ROLLBACK_SEGMENT=1 would help spread things out a
> bit.
>
> Thanks for any help.
>
Received on Tue Jan 04 2000 - 01:00:48 CST