--- In firebird-support@yahoogroups.com, "Leyne, Sean" <Sean@...> wrote:

>
>
>
> > > Vlad,
> > >
> > > > > All applications, well behaved or not, will run into the 20,000
> > > > *interval* as this is the number of transactions since the last
> > sweep.
> > > >
> > > > Think twice on it, please ;)
> > >
> > > I did. What did I get wrong?
> >
> > Sweep interval is not a "number of transactions since the last
> > sweep".
>
> Perhaps it is a 'language' issue but ...

No, i don't think so

> The IB 5.5 documentation describes a sweep being triggered when:
>
> "... the difference between the OIT and the newest transaction reaches the threshold."

Yes. But is didn't state that only sweep can move OIT forward.

> So, in the case of a SuperServer install, where garbage collection is turned off, the above definition will be true when the number of transactions since the last sweep reaches the threshold.

OIT can move forward without a sweep. There is two possible reasons for OIT to stuck :
a) rollback via TIP
b) limbo transaction

else OIT will move forward without a sweep for years despite of number of transactions.

Also, OIT have no relation with background garbage collection in SS.

Regards,
Vlad

PS It is incredible how long such myth's will be alive ;)