Acquires a DB lock. The methods blocks until the requested lock has been obtained. Recursively locking the same lock from within the same thread on the same host is supported. If the host holding a lock leaves the cluster, the lock is automatically released. Note: The locking mechanism is kind of a co-operative locking mechanism: The lock does not prevent other threads from accessing or editing the DB. It only prevents other threads from obtaining the same lock. Locking is an expensive operation and should only be used when absolutely necessary. It must only be used in matching pairs inside batch commands.



return value