Re: DBMS_ALERT.WAITANY questions

Stephane Vanhoecke wrote:

> I have somes questions about DBMS_ALERT package and WAITANY procedure.
>
> The context is :
> An application is waiting for database event (insert in a table).
> This application register a lot of signal identify by a special ID (about
> 1000 signals). This ID is a column of the waiting table.
> A trigger SIGNAL the ID when there is an insertion in the waiting table.
> The application use the WAITANY procedure to reveive events.
>
> Problem is :
> WAITANY don't return SIGNAL in a chronologic order.
> Questions are :
> - In wich order the WAITANY procedure return raised SIGNALS ?
>
> In the documentation, there is a chapter talking about POLLING LOOPS : If
> you use the WAITANY procedure, and if a signalling session does a signal but
> does not commit within one second of the signal.
> - What is the inconvenient of POLLING LOOPS ?
> - Should I use SET_DEFAULTS procedure ?
> - I doesnt' understand how I can set up the POLLING LOOPS ? In the
> documentation there is two different sentences :
> The polling loop begins at a one second interval and exponentially backs
> off to 30-second intervals ?
> SET_DEFAULTS Sensitivity = Polling interval, in seconds, to sleep
> between polls. The default interval is five seconds ?

I can not tell from your post but it might be that the functionality you need would best be implemented using advanced queueing. http://www.psoug.org/reference/library.html Look up DBMS_AQ.

-- 
Daniel Morgan
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