--- In firebird-support@yahoogroups.com, "Alan McDonald" <alan@...> wrote:

>
> > > > Hi,
> > > >
> > > > ODS 10.2 has 2^31 transaction id.
> > > > I believe this spec is some limitation if Firebird is used
> > > > under 24x7 web system.
> > > > I know transaction id is reset when database is back-up/restoring.
> > > >
> > > > I would like to know how to avoid this limitation in your system.
> > > > Please let me know whether FB2.0 change this limitation or not.
> > > >
> > > > Regards.
> > > >
> > > > Daiju
> > >
> > > if you ever do reach this limit, the transaction ID just rolls over.
> > Don't
> > > forget that in a web system the trasnactions are only as long as the
> > page
> > > that is delivered so there are no long running transactions and
> > nothing gets
> > > "stuck"
> > > Alan
> >
> > What happens to the garbage collection when it rolls over? I was under
> > the impression that this limit was a show-stopper that you had to
> > backup-restore pre-emptively to prevent.
> >
> > Adam
>
> a 24x7 system where you don't do regular garbage collection backups?
> Alan
>

Of course this happens nightly, but the oldest transaction will end up
being significantly greater than the current transaction when it rolls
over. I can't see how the MGA mechanisms can work if it simply cycles
over.

To quote Helen "bad things will happen" when the Transaction ID overflows.

(The Firebird Book p512 for details)

Adam