Multiple Notifications enqueued on single queue not dequeued concurrently

Question

Hi,
Oracle 10G database AQ behavior (10.2.0.4.0)
1) Enqueued 5 notifications into Oracle AQ
2) 5 Jobs are being submitted in dba_jobs in different Sessions
3) All 5 notifications are dequeued by Callback procedure in Parallel sessions
Oracle 11G database AQ behavior (11.2.0.3.0)
1) Enqueued 5 notifications into Oracle AQ
2) 1 Job is being submitted in dba_scheduler_jobs
3) 5 notifications are being dequeued by Callback procedure in single session
Is there a way to Dequeue messages concurrently in parallel sessions?
Thanks
Sridhar

Answer 1

Hi Peter,
Throughput has been decreased after moving to 11G.
Background of code:
Call back procedure on AQ we have consists of two parts
1) Dequeue of first message available
2) Calling an another procedure with information from Notification. This procedure processed all records satisfying the information from Notification.
It takes around 6 minutes to process
We have parameter p_var which is configured as 6 and this controls number of dbms_jobs fired as below
LOOP
FOR i in 1..p_var
LOOP
dbms_lock.allocate_unique ('QUEUE1'||i,l_lckhandle_db);
l_rel := dbms_lock.request (l_lckhandle_db, 6, 1, FALSE);
EXIT WHEN l_rel = 0;
END LOOP;
IF l_rel <> 0
THEN
dbms_lock.sleep (10);
END IF;
EXIT WHEN l_rel = 0;
END LOOP;
Suppose we have 10 Notifications enqueued in same second in AQ
10G code flow:
1) 6 jobs were fired and processing was in 6 parallel sessions
11G code flow:
1) only one scheduler job is fired and all 10 notifications are processed in serial.
This is reason for less throughput in 11G.
Do we have any way we can make this process in parallel? (not enqueing notifications in same second and changing any DB level parameter?)
I have an idea to fire a separate dbms_job or scheduler job to process part 2 of callback procedure.
Is this solution we can consider to problem we have or is there any other solution?
Thanks
Sridhar