I am using IBM Websphere MQ. I have the queue manager and queue name. Now, I want to check whether the queue has any messages in it?
I did not work on this before. Pleas help
Please let me know if you need further information!
Thanks
The below code is .NET / amqmdnet - but you might try and convert this in the meantime until a Java dev sees your post.
To see if there is a message on the queue, without actually taking it off the queue, use MQC.MQOO_BROWSE on the Queue and IBM.WMQ.MQC.MQGMO_BROWSE_FIRST as the option
You'll get MQRC_NO_MSG_AVAILABLE if the queue is empty.
MQMessage queueMessage = new MQMessage();
MQQueueManager queueManager = new MQQueueManager(qmName, channelName, connName);
MQQueuequeue = queueManager.AccessQueue(qName,
MQC.MQOO_BROWSE + MQC.MQOO_FAIL_IF_QUIESCING);
MQGetMessageOptions opt = new MQGetMessageOptions();
opt.Options = IBM.WMQ.MQC.MQGMO_BROWSE_FIRST;
queueMessage.CorrelationId = IBM.WMQ.MQC.MQMI_NONE;
queueMessage.MessageId = IBM.WMQ.MQC.MQMI_NONE;
queue.Get(queueMessage, opt);
String sMessage = queueMessage.ReadString(queueMessage.DataLength);
To peek the next message use IBM.WMQ.MQC.MQGMO_BROWSE_NEXT;
To actually read the message OFF the queue, use MQC.MQOO_INPUT_SHARED on the AccessQueue.
The answer didn't show how to check for MQRC_NO_MSG_AVAILABLE. Here is my solution. If there are better ones please let me know.
try
{
queue.Get(queueMessage, opt);
String sMessage = queueMessage.ReadString(queueMessage.DataLength);
}
catch (MQException err)
{
if (err.ReasonCode.CompareTo(MQC.MQRC_NO_MSG_AVAILABLE) == 0)
return true;
}
For Windows machine
It depends on where your queue manager is.
You could use MQUtilities - ih03 pack - which has rfhUtil.exe (Local Qm) and rfhUtilC.exe (for remote qm)
For Local QM , it is straight forward you need to place appropriate values and hit browse, it will show you Queue Depth.
For Remote QM, Place /TCP/(PortNo) for queue manager name and queue for queue name. Hit browse and you will get to know the queue depth.
For Unix/Ubuntu/Linux versions - There is a product called MQVisualEdit which is similar to this one.
Related
Regarding: “Sending response back to the out/reply queue.”
There is a requirement to send the response back to a different queue (reply queue).
While sending the response, we have to use the correlation and message id from the request message and pass it to the reply queue as header. I suspect the format of correlation/message id is wrong.
While reading the message, the correlation id and message id format are as below:
MessageId = “ID:616365323063633033343361313165646139306638346264”
CorrelationId = “ID:36626161303030305f322020202020202020202020202020”
While sending the back to out/reply queue, we are passing these ids as below:
ITextMessage txtReplyMessage = sessionOut.CreateTextMessage();
txtReplyMessage.JMSMessageID = “616365323063633033343361313165646139306638346264”;
txtReplyMessage.JMSCorrelationID = “36626161303030305f322020202020202020202020202020”;
txtReplyMessage.Text = sentMessage.Contents;
txtReplyMessage.JMSDeliveryMode = DeliveryMode.NonPersistent;
txtReplyMessage.JMSPriority = sentMessage.Priority;
messagePoducerOut.Send(txtReplyMessage);
Please note:
With the XMS.NET library, we need to pass the correlation and message id in string format as per shown above
With MQ API’s (which we were using earlier) passing the correlation and message ids we use to send in bytes format like below:
MQMessage queueMessage = new MQMessage();
string[] parms = document.name.Split('-');
queueMessage.MessageId = StringToByte(parms[1]);
queueMessage.CorrelationId = StringToByte(parms[2]);
queueMessage.CharacterSet = 1208;
queueMessage.Encoding = MQC.MQENC_NATIVE;
queueMessage.Persistence = 0; // Do not persist the replay message.
queueMessage.Format = "MQSTR ";
queueMessage.WriteString(document.contents);
queueOut.Put(queueMessage);
queueManagerOut.Commit();
Please help to troubleshoot the problem.
Troubleshooting is a bit difficult because you haven’t clearly specified the trouble (is there an exception, or is the message just not be correlated successfully?).
In your code you have missed to add the “ID:” prefix. However, to address the requirements, you should not need to bother too much about what is in this field, because you simply need to copy one value to the other:
txtReplyMessage.JMSCorrelationID = txtRequestMessage.JMSMessageID
A bit unclear what the issue is. Are you able to run the provided examples in the MQ tools/examples? This approach uses tmp queues(AMQ.*) as JMSReplyTo
Start the "server" application first.
Request/Response Client: "SimpleRequestor"
Request/Response Server: "SimpleRequestorServer"
You can find the exmaples at the default install location(win):
"C:\Program Files\IBM\MQ\tools\dotnet\samples\cs\xms\simple\wmq"
The "SimpleMessageSelector" will show how to use the selector pattern.
Note the format on the selector: "JMSCorrelationID = '00010203040506070809'"
IBM MQ SELECTOR
i have an outOfMemoryException while reading messages from a queue with 2 M of messages.
and i am trying to find a way to read messgages by 1000 for example .
here is my code
List<TextMessage> messages = jmsTemplate.browse(JndiQueues.BACKOUT, (session,browser) -> {
Enumeration<?> browserEnumeration = browser.getEnumeration().;
List<TextMessage> messageList = new ArrayList<TextMessage>();
while (browserEnumeration.hasMoreElements()) {
messageList.add((TextMessage) browserEnumeration.nextElement());
}
return messageList;
});
thanks
Perform the browse on a different thread and pass the results subset to the main thread via a BlockingQueue<List<TextMessage>>. e.g. a LinkedBlockingQueue with a small capacity.
The browsing thread will block when the queue is full. When the main thread removes an entry from the queue, the browser can add a new one.
Probably makes sense to have a capacity at least 2 so that the next list is available immediately.
I need to get the numver of messages passes through the sonic queue per minute via a java code. I need this so i can create an alert when this messages per minute is higher than normal count. Can some on please assist me with this. Thanks
this information should be available via JMX (enqueued/dequeued count).
try to connect to the broker with VisualVM to find the ObjectName and Attributes.
to access sonicmq by JMX :
Hashtable env = new Hashtable( );
env.put(“ConnectionURLs", "tcp://localhost:2506");
env.put("DefaultUser", "Administrator");
env.put("DefaultPassword", "Administrator");
JMSConnectorAddress address = new JMSConnectorAddress(env);
JMSConnectorClient connector = new JMSConnectorClient( );
connector.connect(address);
ObjectName brokerName = new ObjectName(“Domain1.Container1:ID=Broker1”);
MBeanInfo mi = connector.getMBeanInfo(brokerName );
... usual JMX attributes access
I've written a Continuous JMS Message reveiver :
Here, I'm using CLIENT_ACKNOWLEDGE because I don't want this thread to acknowledge the messages.
(...)
connection.start();
session = connection.createQueueSession(true, Session.CLIENT_ACKNOWLEDGE);
queue = session.createQueue(QueueId);
receiver = session.createReceiver(queue);
While (true) {
message = receiver.receive(1000);
if ( message != null ) {
// NB : I can only pass Strings to the other thread
sendMessageToOtherThread( message.getText() , message.getJMSMessageID() );
}
// TODO Implement criteria to exit the loop here
}
In another thread, I'll do something as follows (after successful processing) :
This is in a distinct JMS Connection executed simultaneously.
public void AcknowledgeMessage(String messageId) {
if (this.first) {
this.connection.start();
this.session = this.connection.createQueueSession( false, Session.AUTO_ACKNOWLEDGE );
this.queue = this.session.createQueue(this.QueueId);
}
QueueReceiver receiver = this.session.createReceiver(this.queue, "JMSMessageID='" + messageId + "'");
Message AckMessage = receiver.receive(2000);
receiver.close();
}
It appears that the message is not found (AckMessage is null after timeout) whereas it does exist in the Queue.
I suspect the message to be blocked by the continuous input thread.. indeed, when firing the AcknowledgeMessage() alone, it works fine.
Is there a cleaner way to retrieve 1 message ? based on its QueueId and messageId
Also, I feel like there could be a risk of memory leak in the continuous reader if it has to memorize the Messages or IDs during a long time.. justified ?
If I'm using a QueueBrowser to avoid impacting the Acknowledge Thread, it looks like I cannot have this continuous input feed.. right ?
More context : I'm using ActiveMQ and the 2 threads are 2 custom "Steps" of a Pentaho Kettle transformation.
NB : Code samples are simplified to focus on the issue.
Well, you can't read that message twice, since you have already read it in the first thread.
ActiveMQ will not delete the message as you have not acknowledge it, but it won't be visible until you drop the JMS connection (I'm not sure if there is a long timeout here as well in ActiveMQ).
So you will have to use the original message and do: message.acknowledge();.
Note, however, that sessions are not thread safe, so be careful if you do this in two different threads.
How can we browse all the messages in a WebSphere MQ queue in one API call using java?
Here is the code which I'm using. Here I'm using this code a for loop until q depth is reached.
MQGetMessageOptions gmo=new MQGetMessageOptions();
gmo.options = MQC.MQGMO_WAIT | MQC.MQGMO_BROWSE_NEXT ;
//System.out.println("Status: "+i);
MQMessage out=new MQMessage();
out.format =MQC.MQFMT_XMIT_Q_HEADER;//MQC.MQFMT_REF_MSG_HEADER;
mqCon.getQue().get(out,gmo);
System.out.print(i);
How can I get all messages without using for loop? It's taking a long time to browse 10,000 messages.
How can I get all messages without using for loop?
Use a while loop. Sorry, could not resist a slightly snarky answer on that one. WMQ does not have an API call analogous to the SQL select statement. Messaging and databases share some traits but address fundamentally different requirements.
It's taking a long time to browse 10,000 messages.
Take a look at the Performance SupportPacs. These are published on the SupportPacs main page and have names beginning with MP. Find the one for your platform and MQ version and it will list different scenarios for putting and getting messages as well as performance tuning recommendations.
I would also ask why a normal app needs to browse 10,000 messages. The QMgr will select messages for you based on MsgID, Correlation ID or property and this is much faster than browsing all the messages in order for the application to find the ones of interest. Occasionally people need to browse all messages on a queue to archive the queue or to debug a problem, but this is the exception rather than the rule. If a Production app regularly browses all messages on a queue, then the queues may have been inappropriately used as a database.
How can I get all messages without using for loop?
MQGetMessageOptions getOptions = new MQGetMessageOptions();
getOptions.options = MQC.MQGMO_BROWSE_NEXT + MQC.MQGMO_NO_WAIT + MQC.MQGMO_FAIL_IF_QUIESCING;
MQMessage message = new MQMessage();
byte[] b = null;
while(true)
{
try
{
queue.get(message, getOptions);
b = new byte[message.getMessageLength()];
message.readFully(b);
System.out.println(new String(b));
message.clearMessage();
}
catch (IOException e)
{
System.out.println("IOException: " + e.getMessage());
break;
}
catch (MQException e)
{
if (e.completionCode == 2 && e.reasonCode == MQException.MQRC_NO_MSG_AVAILABLE)
System.out.println("All messages read.");
else
System.out.println("MQException: Completion Code = " + e.completionCode + " : Reason Code = " + e.reasonCode);
break;
}
}
I have posted many Java/MQ samples here:
http://www.capitalware.biz/mq_code_java.html
If you want just browse messeges (not retrive them), you can use javax.jms.QueueBrowser.
Is pretty fast...
import javax.jms.*
...
public ArrayList<Message> browse() {
...
QueueBrowser queueBrowser = queueSession.createBrowser((javax.jms.Queue) lookupQueue());
Enumeration enums = queueBrowser.getEnumeration();
while (enums.hasMoreElements()) {
Object objMsg = enums.nextElement();
if (objMsg instanceof TextMessage) {
TextMessage message = (TextMessage) objMsg;
Log4j.trace("Text message: " + i + ". MSG:" + message.getText() + " MSG id:"
+ message.getJMSMessageID() + " MSG dest:" + message.getJMSDestination());
} else if (objMsg instanceof ObjectMessage) {
ObjectMessage message = (ObjectMessage) objMsg;
Log4j.trace("Object Message: " + i + ". MSG" + " MSG id:" + message.getJMSMessageID()
+ " MSG dest:" + message.getJMSDestination());
}
}
}
...
Just noticed the message format (out.Format) you are using. MQFMT_XMIT_Q_HEADER is used for messages that are sent to a transmit queue. Messages in transmit queue are not generally read by applications. MQ uses a transmit queue to send messages from one queue manager to another queue manager in a MQ network. I hope you are not browsing messages in a transmission queue.
For applications, message format would typically depend on the receiving application. For example if the receiving application is CICS based, then format would be MQFMT_CICS, for IMS it would be MQFMT_IMS. If text/string type of data is expected then you could use MQFMT_STRING. For administering MQ using PCF messages, then format can be MQFMT_PCF.