Re: Rollback segments

"Howard J. Rogers" <howardjr_at_www.com> writes:

> Yes, a huge one. New transactions cannot move into an extent of a rollback
> segment which has an active transaction within it. With just two extents,
> the chances of filling up the second extent and thereby needing to move back
> into the first which is likely to still have one active transaction in it
> (however trivial that transaction is) is extremely high. The more extents
> you have, the lower the probability. When it can't move back into the first
> extent because of the presence of an active transaction, the segment will
> instead acquire (dynamically) an additional extent.

Does each rollback extent contain output from exactly one transaction then? What happens if your rollback segments are not autoexend and you have as many active transactions as you have extents?

Do any of the statistics represent average,min,max rollback space used per transaction? It seems like it should be possible to gather such statistics as well as standard deviation and size the rollbacks carefully.

-- 
greg