> Oldest active 126244
> Next transaction 155285
> Sweep interval: 20000
>
>The difference from the oldest active to the next transaction is almost 30.000.
>
>The sweep interval is 20.000 so I thought the automatic sweeping would
>clear this "lost" transactions when they reach 20.000. Am I wrong?

Why do you mention lost transactions? The transaction is probably still active, i.e. the transaction is started, but not yet committed or rolled back. Note that it doesn't have to be a transaction that modifies data, I think all transactions except those that are both read-only and using read committed isolation counts...

HTH,
Set