You may not want to place a lock on your source table. If you specify 0 (zero) for the timeout option, the block and queue drain are bypassed, and the capture command continues to execute. This could possibly leave the queues in an inconsistent state if data is lost when the mirror table is dropped. The 0 (zero) option was added because you may not want to block your production tables if there is substantial activity. When you choose this option, keep in mind, that the data can become inconsistent in the queues and you will have to execute delete queues and re-synch your data.