2 Replies Latest reply: Feb 3, 2014 7:49 PM by user591655 RSS

Understanding dequeuing process

p.belanger Newbie
Currently Being Moderated

Hi,

 

I'm trying to understand what's going on with some queues in a system i'm debugging.  From the AQ$AVAIL_CHANGE_EVENT_QTAB view i'm seeing messages and some of them are being dequeued with a PROCESSED state and DEQ_TIME.

 

I don't see any dequeue call for this and no callback function, only a subscriber - a consumer.

 

Can someone help me understand how the dequeuing works ?

 

Here's what the DBA gave me :

 

BEGIN
  AQ.CREATE_PRIORITY_QUEUE(QTABLE => 'AVAIL_CHANGE_EVENT_QTAB', PAYLOAD_TYPE => 'AVAIL_CHANGE_EVENT_TYP', QNAME => 'AVAIL_CHANGE_EVENT_Q', MCONSUMERS => TRUE);
END;
BEGIN
   DBMS_AQADM.add_subscriber (queue_name      => user||'.AVAIL_CHANGE_EVENT_Q',
                              subscriber      => SYS.aq$_agent ('farecache',
                                                                NULL,
                                                                NULL
                                                               )
                             );
END;

 

Thanks

 

--

Patrick

  • 1. Re: Understanding dequeuing process
    user648708 Explorer
    Currently Being Moderated

    Hello,

     

    using AQs you cannot "see" any dequeue call based on the AQ$ views, where the processed messages are logged.

    You have an AQ "AVAIL_CHANGE_EVENT_Q" and a specified transportation mechanismen for enqueued messages.

    This could be a scheduled job which permanently waits for new enqueued messages.

    Depending on your specified subscribers these messages will be distributed to the targets.

    Using the AQ$ views you can only see which messages have been processed in the past. Either your DBA or the developers

    of the AQ source code know where you can find the corresponding AQ actions DBMS_AQ.ENQUEUE and DBMS_AQ.DEQUEUE.

     

    Kind regards,

    WoG

  • 2. Re: Understanding dequeuing process
    user591655 Journeyer
    Currently Being Moderated

    Also check below article which may help you.

     

    Event Monitor Process: Architecture and Known Issues (Doc ID 105067.1)


    Thanks

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