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Re: [xmlblaster-devel] how to diagnose subscriber that stops getting messages after a while?


assuming your subscriber logs in with SUB/1

Look under
MBeans -> org.xmLBlaster -> node -> [your cluster node] -> client -> SUB -> session -> 1

Now click on '1' and on the right side you see at the bottom the property "SubscribedTopics", double click
the value of it to see the subscriptions.
Further check if CbQueueNumMsgs = 0 (all messages are delivered)
ConnectionState=ALIVE (xmlBlaster is not polling for the subscribers callback listener)
DispatcherActive=true (xmlBlaster is actively sending messages back to the subscriber)
NumUpdates=23324 (the number of updates send up to now, it should grow)
PingRoundTripDelay=2 (how long does it take for a ping to return)
(click 'Refresh' then and again to update jconsole)

You can start the subscriber client (if java) with
  java -Dcom.sun.management.jmxremote ...
and observe similar values on client side in jconsole.
Also check the threads on deadlock and the memory consumption in jconsole.

-Which OS, JDK, xmlBlaster version do you use?
-How does the client subscribe (XPATH or EXACT)?
-Is there any hint in the log files?


Brad Clements wrote:
Two days in a row, I find that newly published messages are not being
delivered to a subscriber (though, maybe all subscribers are affected, I
only noticed this one not getting messages)

The subscriber is connected, and every 15 seconds it publishes a
"heartbeat" message that is polled (using get) by nagios.

Well, nagios keeps seeing this heartbeat ok, and since the heartbeat
message is set to expire every 60 seconds, this suggests that the
subscriber's publish messages are getting to xml blaster.

So then, it seems that the subscriber's inbound queue is stuck or

I have jconsole working, how can I check to see where the problem lies?

When I detect this condition, I have to restart xmlblaster immediately,
because we can't afford any downtime.

So, I'm looking for a "next time, check this and this" suggestion so I'll
have a plan of action when this occurs again.

also, this subscriber really has a low message rate, so I don't think it's
stopped responding to incoming messages. When I restart xmlblaster, the
subscriber automatically reconnects.. But to be sure if it's a subscriber
problem, where do I look in jconsole?


Brad Clements, _bkc at murkworks.com_ (315)268-1000
_http://www.murkworks.com_ AOL-IM or SKYPE: BKClements