[英]Why can't I get performance boost while changing persistent activemq messages to non-persistent?
[英]Can't get ActiveMQ to resend my messages
我有一個用Java編寫的單線程ActiveMQ使用者。 我要做的就是從隊列中接收()一個消息,嘗試將其發送到Web服務,如果成功則確認()它。 如果Web服務調用失敗,我希望消息保留在隊列中並在超時后重新發送。
除了重新發送部分之外,它或多或少都在工作:每次重新啟動我的消費者時,它會為仍然在隊列中的每個消息收到一條消息,但是在發送它們之后,消息永遠不會被重新發送。
我的代碼看起來像:
public boolean init() throws JMSException, FileNotFoundException, IOException {
ActiveMQConnectionFactory connectionFactory = new ActiveMQConnectionFactory(user, password, url);
RedeliveryPolicy policy = new RedeliveryPolicy();
policy.setInitialRedeliveryDelay(500);
policy.setBackOffMultiplier(2);
policy.setUseExponentialBackOff(true);
connectionFactory.setRedeliveryPolicy(policy);
connectionFactory.setUseRetroactiveConsumer(true); // ????
Connection connection = connectionFactory.createConnection();
connection.setExceptionListener(this);
connection.start();
session = connection.createSession(transacted, ActiveMQSession.INDIVIDUAL_ACKNOWLEDGE);
destination = session.createQueue(subject); //???
consumer = session.createConsumer(destination);
//consumer.setMessageListener(this); // message listener had same behaviour
}
private void process() {
while(true) {
System.out.println("Waiting...");
try {
Message message = consumer.receive();
onMessage(message);
} catch (JMSException e) {
e.printStackTrace();
}
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
@Override
public void onMessage(Message message) {
System.out.println("onMessage");
messagesReceived++;
if (message instanceof TextMessage) {
try {
TextMessage txtMsg = (TextMessage) message;
String msg = txtMsg.getText();
if(!client.sendMessage(msg)) {
System.out.println("Webservice call failed. Keeping message");
//message.
} else {
message.acknowledge();
}
if (transacted) {
if ((messagesReceived % batch) == 0) {
System.out.println("Commiting transaction for last " + batch + " messages; messages so far = " + messagesReceived);
session.commit();
}
}
} catch (JMSException e) {
e.printStackTrace();
}
}
}
我目前沒有使用交易(也許我應該這樣做?)。
我確定我錯過了一些簡單的東西,很快就會拍打我的額頭,但我似乎無法弄清楚這是怎么回事。 謝謝!
編輯:由於代表不夠,我自己無法回答:
好的,經過一些實驗,事實證明交易是實現這一目標的唯一方法。 這是新代碼:
public boolean init() throws JMSException, FileNotFoundException, IOException {
ActiveMQConnectionFactory connectionFactory = new ActiveMQConnectionFactory(user, password, url);
RedeliveryPolicy policy = new RedeliveryPolicy();
policy.setInitialRedeliveryDelay(1000L);
policy.setMaximumRedeliveries(RedeliveryPolicy.NO_MAXIMUM_REDELIVERIES);
connectionFactory.setRedeliveryPolicy(policy);
connectionFactory.setUseRetroactiveConsumer(true);
Connection connection = connectionFactory.createConnection();
connection.setExceptionListener(this);
connection.start();
session = connection.createSession(transacted, ActiveMQSession.CLIENT_ACKNOWLEDGE);
destination = session.createQueue(subject);
consumer = session.createConsumer(destination);
}
@Override
public void onMessage(Message message) {
System.out.println("onMessage");
messagesReceived++;
if (message instanceof TextMessage) {
try {
TextMessage txtMsg = (TextMessage) message;
String msg = txtMsg.getText();
if(client.sendMessage(msg)) {
if(transacted) {
System.out.println("Call succeeded - committing message");
session.commit();
}
//message.acknowledge();
} else {
if(transacted) {
System.out.println("Webservice call failed. Rolling back message");
session.rollback();
}
}
} catch (JMSException e) {
e.printStackTrace();
}
}
}
現在,按照“重新傳遞策略”中的指定,每1000毫秒重新發送一條消息。
希望這有助於其他人! :)
您不必使用事務,CLIENT_ACK / Session.recover()也可以使用...
發生以下任何情況時,會將郵件重新傳遞給客戶端:
- 使用事務會話並調用rollback()。
- 在調用commit之前關閉事務會話。
- 會話正在使用CLIENT_ACKNOWLEDGE並調用Session.recover()。
請參閱http://activemq.apache.org/message-redelivery-and-dlq-handling.html
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