> I read somewhere that the "read only" transactions are absolutelly harmless to the GC and sweeping. Is that so?

>>Read only transactions only physically have an impact on the TIP/Header page(s), however a long running read only transaction
>>will have the same effect as a long running read write transaction in that it will block GC and sweeps until it
>>commits.

<<may i ask why readonly readcommited transaction block GC?
Is this true?>>

Karol,

I was referring to the default transaction state of snapshot (repeatable read)....
Other transaction states will have different effects. In your case
read commited needs only the newest record version (or record versions created by
the transaction itself) so its not going to block anything.

Paul