I have a queue that is setup with dblink propagation that stopped propagating its messages. We are running this on several of our systems and this has been running successfully in this particular environment for almost year. One thing to note is approx a month ago this occurred and I dropped and rebuilt the queue given its not production. To troubleshoot - I created a 2nd queue and that too stopped working after approximately 30 minutes (I enQ right after it was created, about 5 minutes later and then again after another 20 minutes) the last request did not DeQ as the first two did. This is a low volume queue so processes only a handful of requests throughout the day on a normal basis. I have verified the following items:
dblink for the destination queue is valid;
in DBA_QUEUE_SCHEDULES.schedule_disabled = N and there are no errors being reported.
we are running Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production on exadata.
When it stops working I have used dbms_aqadm.unschedule_propagation followed by dbms_aqadm.schedule_propagation and it works for a few minutes.
Has anyone else seen this happen and / or have suggestion for further trouble-shooting? thanks in advance.