MDB Poison message

[Dave Teare]

Hi all,
What does WebSphere do if a message delivered to an MDB fails multiple times? (i.e. fails more than the maximum retry setting) I assume it must store it somewhere for an admin to look at. Where is this and what tools are available to process / review them?
I want to use a MDB to process credit card orders and don't want to worry about lost messages. Of course I will use CMT s.t. if the MDB fails the message will be returned to the queue, but I am worried about poisoned messages.
Thanks!
--Dave.

[Peter Kristensson]

Hi.
My experience on this is dependant on how they fail.
If you throw an exception during your processing of the messages, the WAS will likely just shut down the listener port on the server.
This will leave the messages on the queue and WAS will attempt to process them once again when you open up the listener port.
/Peter

[jai deep]

Hi Peter,

We are developing an application and we are facing a problem. I am using using WAS 5.1 and MQ simulator. I am sending email messages using JMS. I have configured the Queue and Queue connection factory as well as Listener port. Most of the time the code works fine but sometime the listener get stopped and we have to start it again.

We do not want to start out Listener again and again to send message. On java ranch you have suggested that exception in code could make Listener port stop working.

My onMessage method is as follows:-

 public void onMessage(javax.jms.Message msg) {
try {
log.debug("Invoking MDB onMessage() now.");
msgId = msg.getJMSMessageID();
log.debug("msgId" + msgId);

if (previousMessages.containsKey(msgId)) {
count = ((Integer) previousMessages.get(msgId)).intValue();
} else {
count = 0;
}
 
/*   if msg has been retried couple of times, discard it.  and remove the stored id. */
/* Handling of non delevered message */
log.debug("count=" + count);
if (count > NO_OF_RETRIES-1) {

previousMessages.remove(msgId);
return;
}
log.debug("Mail object " + mail);
mail = (Email) ((ObjectMessage) msg).getObject();
log.debug(" mail.getEmailAddressTo() " +  mail.getEmailAddressTo());
if ( mail.getEmailAddressTo() == null) {
email.sendMessageToMultiple(mail);
}else{
email.sendMessage(mail);
}

if (previousMessages.containsKey(msgId)) {
previousMessages.remove(msgId);
}
} catch (JMSException e) {
log.debug("Whoops!A JMSException occurred previous: " + e);
fMessageDrivenCtx.setRollbackOnly();
previousMessages.put(msgId, new Integer(++count));
log.debug("Whoops!A JMSException occurred: " + e);
 
} catch (Exception e) {
log.debug("Whoops!A Exception occurred previous: " + e);
fMessageDrivenCtx.setRollbackOnly();
previousMessages.put(msgId, new Integer(++count));
 
}
 
}
 

It is using emailutility class for sending message. Here what changed I should do for not stopping Listener port?


with regards
Jai
[ December 01, 2004: Message edited by: jai deep ]