Re: ROLLBACK

Seema Singh wrote:
>
> Hi
> One of production database showing waits in v$waitstat like
> CLASS COUNT
> undo header 300
> and undo block 38
> I saw in v$rollstat and found wraps in rollback segment.
> But I haven't see contention in rollback segment.What is the group view?
> Can I increase extent size or not?
> Thanks
> -Seema

Seema,

   It's not a matter of extent size, it's a sheer matter of number of rollback segments. You do not have enough, and transactions are scrambling for slots (if you have ever passed through a busy airport, you get the picture. You need more runways).   Official figure is one for about 4 concurrent active transactions, up to 50.

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Regards,

Stephane Faroult
Oriole Corporation
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Author: Stephane Faroult
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