with standby_access causes dump transaction to dump only completed transactions. It dumps the transaction log up to the point at which there are no active transactions. If you do not use with standby_access, the entire transaction log, including records for all open transactions is dumped.
Figure 13-1: Dump cut-off point for dump transaction with standby_access
In Figure 13-1, a dump transaction...with standby_access command is issued at a point where transactions T1 through T5 have completed and transaction T6 is still open. The dump cannot include T5 because T6 is still open, and it cannot include T4, because T5 is still open. The dump must stop at the end of T3 (which is just before the dump cut-off point), where it includes completed transactions T1 through T3.
