Oracle Built−in Packages- P59: Ah, for the good old days of Version of PL /SQL! Life was so simple then. No stored procedures or functions and certainly no packages. You had your set of built−in functions, like SUBSTR and TO_DATE. You had the IF statement and various kinds of loops. With these tools at hand, you built your batch−processing scripts for execution in SQL*Plus, and you coded your triggers in SQL*Forms , and you went home at night content with a good day's work done. | Appendix A What s on the Companion Disk start_time Initial start date-time for the window of time in which messages are propagated from the source queue to the destination queue. duration Length of time in seconds that the propagation window will be open. If you supply a NULL value the default then the propagation window is open continually or at least until the propagation is unscheduled through a call to . next_time An expression returning a date value that is used to compute the start of the next propagation window. If you supply a NULL value the default then propagation will stop when the current initial window closes. As an example suppose you want to make sure the next propagation doesn t start until 24 hours after the last propagation window closed. You would then set next_time to SYSDATE 1 - duration 86400. If you want to make sure the next propagation starts 24 hours after the last propagation window closed provide a next_time value of SYSDATE 1 . latency The maximum wait in seconds that a message may sit in a queue after the start of a propagation window before it is propagated. The default amount of time is 60 seconds. This would mean for example that when the propagation window opens the Queue Monitor propagates any messages present. It would then wait 60 seconds or until the window closes due to the duration setting before checking for the presence of and propagating any other messages. To summarize that relatively complex set of parameters and their interactions when you schedule propagation you identify an initial start date time and a span of time number of seconds in which messages are available to be propagated out of the queue to other queues. You can request that this window of time be opened on a regular basis every day once a week every morning at 10 . etc. . Finally you can specify that the Queue Monitor check no less frequently than every N seconds latency during the time the propagation window is open to .
