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fix for AMQ-575 to avoid the deadlock when removing consumers, which can sometimes cause messages to be redispatched when another consumer is ack-ing a message. a good lesson this one - keep locks for as short a time as possible 

git-svn-id: https://svn.apache.org/repos/asf/incubator/activemq/trunk@378268 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
James Strachan 2006-02-16 15:06:00 +00:00
parent e82d0fb470
commit dba97b77c5
1 changed files with 21 additions and 14 deletions
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35
activemq-core/src/main/java/org/apache/activemq/broker/region/Queue.java
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@ -187,12 +187,14 @@ public class Queue implements Destination {
ConsumerId consumerId = sub.getConsumerInfo().getConsumerId(); ConsumerId consumerId = sub.getConsumerInfo().getConsumerId();
MessageGroupSet ownedGroups = getMessageGroupOwners().removeConsumer(consumerId); MessageGroupSet ownedGroups = getMessageGroupOwners().removeConsumer(consumerId);
synchronized (messages) { if (!sub.getConsumerInfo().isBrowser()) {
if (!sub.getConsumerInfo().isBrowser()) { MessageEvaluationContext msgContext = context.getMessageEvaluationContext();
MessageEvaluationContext msgContext = context.getMessageEvaluationContext(); try {
try { msgContext.setDestination(destination);
msgContext.setDestination(destination);
// lets copy the messages to dispatch to avoid deadlock
List messagesToDispatch = new ArrayList();
synchronized (messages) {
for (Iterator iter = messages.iterator(); iter.hasNext();) { for (Iterator iter = messages.iterator(); iter.hasNext();) {
IndirectMessageReference node = (IndirectMessageReference) iter.next(); IndirectMessageReference node = (IndirectMessageReference) iter.next();
if (node.isDropped()) { if (node.isDropped()) {
@ -202,20 +204,25 @@ public class Queue implements Destination {
String groupID = node.getGroupID(); String groupID = node.getGroupID();
// Re-deliver all messages that the sub locked // Re-deliver all messages that the sub locked
if (node.getLockOwner() == sub || wasExclusiveOwner if (node.getLockOwner() == sub || wasExclusiveOwner || (groupID != null && ownedGroups.contains(groupID))) {
|| (groupID != null && ownedGroups.contains(groupID))) { messagesToDispatch.add(node);
node.incrementRedeliveryCounter();
node.unlock();
msgContext.setMessageReference(node);
dispatchPolicy.dispatch(context, node, msgContext, consumers);
} }
} }
} finally { }
msgContext.clear();
// now lets dispatch from the copy of the collection to avoid deadlocks
for (Iterator iter = messagesToDispatch.iterator(); iter.hasNext();) {
IndirectMessageReference node = (IndirectMessageReference) iter.next();
node.incrementRedeliveryCounter();
node.unlock();
msgContext.setMessageReference(node);
dispatchPolicy.dispatch(context, node, msgContext, consumers);
} }
} }
finally {
msgContext.clear();
}
} }
} finally { } finally {
dispatchValve.turnOn(); dispatchValve.turnOn();
} }