> Garbage is not much problem - it can be removed
> by sweep, but sooner or later it will be removed
> by normal cooperative garbage collection anyway.
>
> What is the problem is stuck OIT, which can slow down
> starting new transactions and increase memory demands
> for each snapshot transaction.
> But even OIT is not problem in most applications,
> since it can stuck only on some relatively rare occasions -
> either after server crash, or after rollback of transaction
> that updated lot of data.
> There are only two ways how to get rid of stuck OIT -
> by sweep, or by creating new database (i.e. backup/restore).
>
> Regarding auto-sweep - it dos not start every 20000 transactions !!!
> It starts when difference between OIT and OAT is 20000 !
> which usually means when OIT get stuck; in most applications
> automatic sweep will never start !

Huch, nice to see that's not only me, but also Ivan, who
mentions the OAT and *not* the next transaction, when talking
about the sweep interval. Many people still think that the
sweep interval has something to do with the next transaction.

;-)



Best Regards,
Thomas Steinmaurer
LogManager Serie - Logging/Auditing Suites supporting
InterBase, Firebird, Advantage Database and MS SQL Server
Upscene Productions
http://www.upscene.com