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  1. ActiveMQ
  2. AMQ-6194

Deleting a temporary queue creates a warning message in the broker

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    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Minor
    • Resolution: Fixed
    • Affects Version/s: 5.12.1, 5.13.1
    • Fix Version/s: 5.13.4, 5.14.0
    • Component/s: Broker, JMS client
    • Labels:
      None

      Description

      When deleting a temporary queue, the ActiveMQ 5.13.1 (and 5.12.2) broker logs the following warning message:

      INFO  [ActiveMQ NIO Worker 111] [TempQueue] temp-queue://ID:brokerHostname-57582-1455804170203-8569:1:1 on dispose, purge of 1 pending messages: org.apache.activemq.broker.region.cursors.VMPendingMessageCursor@e0f6196
      WARN  [ActiveMQ NIO Worker 111] [Queue] temp-queue://ID:brokerHostname-57582-1455804170203-8569:1:1 after purge of 1 messages, message count stats report: 1
      

      The cause of this warning seems to be the publication of a "ghost" message when sending a single message on the temporary queue from a transacted session, as demonstrated by this test class:

      import java.text.SimpleDateFormat;
      import java.util.Date;
      
      import javax.jms.Connection;
      import javax.jms.JMSException;
      import javax.jms.MessageProducer;
      import javax.jms.Session;
      import javax.jms.TemporaryQueue;
      import javax.jms.TextMessage;
      
      import org.apache.activemq.ActiveMQConnectionFactory;
      
      public class GhostMessageOnTempQueueWithTransactedSessionDemo {
          public static void main(final String[] args) throws JMSException {
              final ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory("tcp://localhost:61616");
              Connection connection = null;
              Session session = null;
              MessageProducer producer = null;
              TemporaryQueue temporaryQueue = null;
              try {
                  connection = factory.createConnection();
                  connection.start();
                  // The session has to be transacted for the second "ghost" message to appear (see below).
                  session = connection.createSession(true, Session.SESSION_TRANSACTED);
                  // And the publication has to be on a temporary queue (if the temporary queue is created by another process, the second "ghost" message still appears).
                  temporaryQueue = session.createTemporaryQueue();
                  producer = session.createProducer(temporaryQueue);
                  final TextMessage textMessage = session.createTextMessage();
                  textMessage.setText("GhostMessageDemo@" + new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss,SSSZ").format(new Date()));
      
                  producer.send(textMessage);
                  // Here, in ActiveMQ 5.13.1 and 5.12.2, the message was sent but cannot be browsed or consumed. It can however be seen in the JMX console with:
                  // - EnqueueCount, that was increased by one;
                  // - MemoryUsageByteCount (by sending huge messages of different size to ensure that it is indeed the real message).
                  // In ActiveMQ 5.10.2 (and 5.4.1), it is not sent (even though SocketOutputStream.socketWrite is still called through TcpFormat.oneway?).
      
                  session.commit();
                  // Here, in ActiveMQ 5.13.1, a "ghost" message was sent (EnqueueCount has increased by one again) and the real message is visible and can be consumed.
                  // If rollback is called instead, the real message stays (and cannot be consumed since the "ghost" message is not sent).
              } finally {
                  if (producer != null)
                      producer.close();
                  if (temporaryQueue != null)
                      // Here, if there was a consumer on the queue, it would have consumed the real message, leaving the "ghost" message that lead to the broker warning.
                      temporaryQueue.delete();
                  if (session != null)
                      session.close();
                  if (connection != null) {
                      connection.stop();
                      connection.close();
                  }
              }
          }
      }
      

        Attachments

        1. AMQ6194Test.java
          3 kB
          Christopher L. Shannon

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            • Assignee:
              cshannon Christopher L. Shannon
              Reporter:
              DavidD David Dou
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              Dates

              • Created:
                Updated:
                Resolved: