How about "first transaction which uses 50mb of your single extent has
finished before the last 20mb transaction will being run "?
Thomas Jork <tj_at_net-dept.de> wrote in message
news:38B28F0A.2B733609_at_net-dept.de...
> hi mike
>
> a transaction uses extents of a rollback segment in an ordered circular
fashion
> and
> a transaction can reuse an extent within a rollback segment ONLY if it is
free
> or inactive.
> so if your first transaction uses 50mb of your single extent and the next
70mb
> transaction starts,
> you 're running in trouble with your last 20mb of the second transaction,
> because oracle can't
> reuse this already used extent.
>
> BUT, why will you use only one extent. i can not see any reason to do it
this
> way
>
>
> thomas
>
> Mike Ng schrieb:
>
> > Hi all,
> >
> > I have asked the following question before, and Mr. Anjum have answered
me.
> > But now I have another question.
> > Assume I have four rollback segment and each have one 100 meg extent.
> >
> > initial 102400 k, next 0 k, minextent 1, maxextent 1
> >
> > Assume that no one transaction will use more than 100 Meg, and one
> > transaction must finish before another transaction will use to exceed
100
> > meg. Now, two transactions run in the same rollback segemt. One use 50
meg
> > size and another use 70 meg size in rollback segment. Assume that first
> > transaction finish the job before the second transaction will use the
size
> > exceed 100 meg. I have a question here that
> >
> > Can the second transaction use the rollback segment which was freed by
first
> > transaction in the SAME extent?
> >
> > I have the above question since I see all example that the space freed
is
> > based on extent scale, not block scale. So I doubt the second
transaction
> > cannot reuse the space freed by first transaction.
> >
> > If the above case is workable, the performance should be the best. Right
or
> > wrong?
> >
> > Thanks to answer my stupid question in advanced.
> >
> > Best Regards,
> > Mike Ng
> >
> > In article <38b1fdc0_3_at_news1.prserv.net>,
> > "Mike Ng" <mike_at_email.tech-trans.com> wrote:
> > > Hi all,
> > >
> > > I hava a question that
> > > Can I allocate a very large extent for each rollback segment? Multiple
> > > transactions can use the same extent in rollback segment. Is it right?
> > Or
> > > one new transaction need at least one new extent in rollback segment.
> > > It makes me mess.
> > >
> > > Thanks in advanced.
> > >
> > > Best regards,
> > > Mike Ng
> > >
> > >
>
Received on Tue Feb 22 2000 - 07:59:07 CST
