[SNMP4J] Snmp Async Thread Pool

[Smith, Ryan]

Sean,
Thanks for the heads up, that's good to know.  As far as I know though,
I'm not using MultiThreadedMessageDispatcher.  I just sent out my
example on the mailing list taken straight from the SNMP.html javadoc
example: http://www.snmp4j.org/doc/org/snmp4j/Snmp.html
With some slight modifications to get it to run.

Ill keep digging around, I wish this example was using the threadPool,
so I could call .shutdown() on it.

Thanks,
-Ryan

-----Original Message-----
From: Gibbons, Sean [mailto:Sean.Gibbons at trueposition.com] 
Sent: Monday, July 16, 2007 1:31 PM
To: Smith, Ryan; Frank Fock
Cc: snmp4j at agentpp.org
Subject: RE: [SNMP4J] Snmp Async Thread Pool

I think it's a potential bug in the code.  If you are using a
MultiThreadedMessageDispatcher object, it creates the threadpool, and
runs it.  But there doesn't seem to be a function in the
MultiThradedMessageDispatcher class that will cancel the ThreadPool.  In
my own program, I made my own multithreaded dispatcher with a stop()
method that calls the stop() method in the threadpool.  Eclipse does not
show any calls to the threadpool stop() method within the SNMP4j API.  

-----Original Message-----
From: snmp4j-bounces at agentpp.org [mailto:snmp4j-bounces at agentpp.org] On
Behalf Of Smith, Ryan
Sent: Monday, July 16, 2007 1:16 PM
To: Frank Fock
Cc: snmp4j at agentpp.org
Subject: RE: [SNMP4J] Snmp Async Thread Pool

Thanks Frank,

I think maybe my language was misleading.  I'm not sure there's a thread
pool per se , So please allow me to make my test case simpler here:

I am using the sample code from:
http://www.snmp4j.org/doc/org/snmp4j/Snmp.html

"An asynchronous SNMPv1 request is sent by the following code:

   // setting up target
   CommunityTarget target = new CommunityTarget();
   target.setCommunity(new OctetString("public"));
   target.setAddress(targetAddress);
   target.setRetries(2);
   target.setTimeout(1500);
   target.setVersion(SnmpConstants.version1);
   // creating PDU
   PDU pdu = new PDU();
   pdu.add(new VariableBinding(new OID(new int[] {1,3,6,1,2,1,1,1})));
   pdu.add(new VariableBinding(new OID(new int[] {1,3,6,1,2,1,1,2})));
   pdu.setType(PDU.GETNEXT);
   // sending request
   ResponseListener listener = new ResponseListener() {
     public void onResponse(ResponseEvent event) {
       // Always cancel async request when response has been received
       // otherwise a memory leak is created! Not canceling a request
       // immediately can be useful when sending a request to a
broadcast
       // address.
       ((Snmp)event.getSource()).cancel(event.getRequest(), this);
       System.out.println("Received response PDU is:
"+event.getResponse());
     }
   };
   snmp.sendPDU(pdu, target, null, listener); "

And it all seems to work, I can see the SNMP Packets being sent over the
network via Wireshark, and all the VariableBindings are there.

But I noticed in this example, my *main* thread exists, while the async
request seems to be keeping a thread alive for a long time (forever?)

I assumed there was a thread pool of 10 b/c in my Eclipse debug window,
10 threads get created (no more).  A new thread gets created for each
"retry" ( I have mine set to 3 retries )  So by the 4th Async message I
send, there are 10 threads running there, waiting, while the main thread
is already done.   So, I think I over complicated the actual question I
was trying to ask.   :)

Im just wanting to know, why after I call the async method, my main
thread can die, but the async thread stays alive?   And how do I
Interrupt or notify all the waiting threads to exit.   Thank you.

-Ryan
 

-----Original Message-----
From: Frank Fock [mailto:fock at agentpp.com]
Sent: Monday, July 16, 2007 1:00 PM
To: Smith, Ryan
Cc: snmp4j at agentpp.org
Subject: Re: [SNMP4J] Snmp Async Thread Pool

Hi Ryan,

Snmp does not use any ThreadPool so I think your problem is caused by
the application not the SNMP4J API.

Best regards,
Frank

Smith, Ryan wrote:
>  
>  
> Hello,
>  
> When I try to send 100 PDU() objects via the .send() or .inform() 
> methods (async) I see that a thread pool of up to 10 threads are 
> created.
>  
> When my program is finished running, the main thread ends, but the 
> threads in the thread pool remain running, (all 10) causing the 
> application to hang (not exit).  I'm calling: ((Snmp) 
> event.getSource()).cancel(event.getRequest(), this) in the callback 
> method.
> I configure the snmp class to timeout sends after 5 seconds and retry
> 3 times before giving up.
>  
> Now, the snmp Manager I'm trying to send to is on udp:192.0.1.123:162

> - This machine doesn't exist.  So the host is unreachable and all the 
> requests timeout,  the only problem is that the threads aren't dying 
> as I expect they should.  I'm not sure what else I'm missing here, any

> ideas?
>  
> Thank you,
> -Ryan
> _______________________________________________
> SNMP4J mailing list
> SNMP4J at agentpp.org
> http://lists.agentpp.org/mailman/listinfo/snmp4j

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