This simple example will show connections accumulating in CLOSE_WAIT on a
2.6.31 Linux kernel (Ubuntu) and Solaris10. This is true for the most
recent release 5.3.0 and 5.1.X (which I am currently using).
I have read the forum entries relating the issues relating to CLOSE_WAIT,
but there seems to be no conclusive reason why this is actually happening.
I have tried a number of configuration options, as suggested by the forum -
including the use of (not available to 5.1.X)
<transportConnectors>
<transportConnector name="openwire"
uri="tcp://localhost:61616?transport.closeAsync=false"/>
</transportConnectors>
but none seem to prevent it from happening.
As lifted from the most trivial of "hello worlds"
public static void main(String[] args) throws Exception
{
int i = 0;
while(i++ < 1000)
{
SendTest sendTest = new SendTest();
sendTest.send();
}
}
private void send()
{
try {
ActiveMQConnectionFactory connectionFactory = new
ActiveMQConnectionFactory("tcp://127.0.0.1:61616");
Connection connection =
connectionFactory.createConnection();
connection.start();
Session session = connection.createSession(false,
Session.AUTO_ACKNOWLEDGE);
Destination destination =
session.createQueue("TEST.FOO");
MessageProducer producer =
session.createProducer(destination);
producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT);
String text = "Hello world! From: " +
Thread.currentThread().getName() + " : " + this.hashCode();
TextMessage message = session.createTextMessage(text);
System.out.println("Sent message: "+ message.hashCode()
+ "
: " + Thread.currentThread().getName());
producer.send(message);
session.close();
connection.close();
}
catch (Exception e) {
System.out.println("Caught: " + e);
e.printStackTrace();
}
}
Running it results in the following,
a...@frogl:~/apps/apache-activemq-5.3.0/bin$ netstat -a |grep CLOSE
tcp6 0 0 localhost:61616 localhost:46831
CLOSE_WAIT
tcp6 0 0 localhost:61616 localhost:46944
CLOSE_WAIT
tcp6 0 0 localhost:61616 localhost:46856
CLOSE_WAIT
tcp6 0 0 localhost:61616 localhost:46978
CLOSE_WAIT
tcp6 0 0 localhost:61616 localhost:46489
CLOSE_WAIT
tcp6 0 0 localhost:61616 localhost:46890
CLOSE_WAIT
tcp6 0 0 localhost:61616 localhost:47257
CLOSE_WAIT
a...@frogl:~/apps/apache-activemq-5.3.0/bin$
I am well aware that re-using the connection is preferable. Can anybody
provide any additional insight as to why these connections result in
CLOSE_WAITs? Thanks in advance
--
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