Re: RBS waits

"Jayaraman Ashok" <ashok_jayaraman_at_yahoo.com> wrote in message news:7ca2852.0208070503.28e88693_at_posting.google.com...
> Hi
> Te following is the status of my database. It has been running for 3
> days now. Though i have 55 rollback segments , i always seem to have
> contention for it. transactions_per_rollback_segment = 10, and the
> rollback segments have initial 5m next 5m minextents 20. There are
> about 100 users connected at any point of time and around 30 - 40
> concurrent transactions. Where is the problem?
>
> SQL> select * from v$waitstat;
>
> CLASS COUNT TIME
> ------------------ ---------- ----------
> data block 18024355 24968386
> sort block 0 0
> save undo block 0 0
> segment header 93 665
> save undo header 0 0
> free list 0 0
> extent map 0 0
> bitmap block 0 0
> bitmap index block 0 0
> unused 0 0
> system undo header 0 0
>
> CLASS COUNT TIME
> ------------------ ---------- ----------
> system undo block 0 0
> undo header 1827 121484
> undo block 13504 43563
>
> Please help.
>
> Ashok

According to your stats you have a way bigger problem with waits for data blocks.
Also, according to the rule of 4 you only need 25 rollback segments. It looks like several of your transactions are hitting the same tables, I would start revising initrans on the affected tables first.

Hth

--
Sybrand Bakker
Senior Oracle DBA

to reply remove '-verwijderdit' from my e-mail address