Re: Which RBS is my Update using ?

"Daniel Morgan" <dmorgan_at_exesolutions.com> wrote in message news:3D8F8B35.339D051C_at_exesolutions.com...
> Paul Brewer wrote:
>
> > "Daniel Morgan" <dmorgan_at_exesolutions.com> wrote in message
> > news:3D8E4E10.8AAABEFC_at_exesolutions.com...
> > > Paul Brewer wrote:
> > >
> > > > "Daniel Morgan" <dmorgan_at_exesolutions.com> wrote in message
> > > > news:3D88D674.1619D215_at_exesolutions.com...
> > > > > Tanel Poder wrote:
> > > > >
> > > > > > Hello,
> > > > > >
> > > > > > > What you are missing ... is that rollback segments need to be
able
> > to
> > > > expand to
> > > > > > > handle the largest transaction on the system. That is not the
same
> > as
> > > > saying they
> > > > > > > need to permanently be large enough to handle the largest
> > transaction
> > > > on the
> > > > > > > system.
> > > > > >
> > > > > > I still don't see why rollback segments in my configuration are
less
> > > > > > expandable than "They should all be identical and sized to
handle
> > the
> > > > > > largest transaction on the system" configuration which you
posted
> > > > > > yesterday..
> > > > > >
> > > > > > But about the cheap price of disk v.s. administration work cost,
I
> > agree
> > > > > > with you.
> > > > > >
> > > > > > Thank you for your time,
> > > > > > Tanel.
> > > > >
> > > > > I'm not sure I understand your question. Rollback segments expand.
And
> > > > expand until
> > > > > they either hit the maximum allowed extents parameter or run out
of
> > disk
> > > > space. So as
> > > > > long as any rollback segment can expand enough to hold any
transaction
> > > > which rollback
> > > > > segment becomes irrelevant.
> > > > >
> > > > > If you try to force a transaction into a specific rollback
segment.
> > And
> > > > for any reason
> > > > > that specific segment is unavailable. The transaction will fail.
> > > > >
> > > > > Daniel Morgan
> > > > >
> > > >
> > > > OK, I'll rise to this one.
> > > >
> > > > Our organisation runs Peoplesoft in Atlanta.
> > > > Each morning at 3 a.m. we replicate about 80 of the Peopleshit
tables
> > back
> > > > to the U.K., then sort them out into something like a rational
structure
> > for
> > > > reporting purposes.
> > > > So, during the day, the U.K. tables are read only, and we don't need
> > much by
> > > > way of rollback segments. However, during the actual replication
process
> > we
> > > > need to use a segment ROLL_BIG, so that the entire refresh group
will
> > either
> > > > succeed or fail.
> > > >
> > > > Paul
> > >
> > > And your point is? ;-)
> > >
> > > All I said was make all of your rollback segments capable of expanding
to
> > be as
> > > large as ROLL_BIG. The cost of doing this is zero.
> > >
> > > Smaller transactions won't ever expand beyond whatever transactions
they
> > > receive. But if they do end up being the rollback segment chosen for
the
> > nightly
> > > process ... they will not fail. Right now you have a single point of
> > failure.
> > >
> > > Daniel Morgan
> > >
> > Daniel,
> >
> > ROLL_BIG is offline during the day. The nightly session brings it
online,
> > does 'set transaction use rollback segment ROLL_BIG', does its work,
then
> > takes it offline again.
> > The other rollback segments are all equally sized (and much smaller).
> > What's wrong with that?
> >
> > Regards,
> > Paul
>
> Nothing until the first time something goes wrong: Then everything.
>
> What's wrong with resizing all of your rollback segments?
>
> Daniel Morgan

Daniel,

Why should they all be 1 gig on a read-only database?

Paul Received on Mon Sep 23 2002 - 17:07:10 CDT