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https://issues.apache.org/activemq/browse/AMQ-2908?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=63059#action_63059
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Gary Tully commented on AMQ-2908:
---------------------------------
I tried to reproduce this issue with a test case. The test case is committed at
apache as it works ok:
http://svn.apache.org/viewvc/activemq/trunk/activemq-core/src/test/java/org/apache/activemq/usecases/ExpiredMessagesWithNoConsumerTest.java?view=diff&r1=1031135&r2=1031136&pathrev=1031136
It is a variant of a slow consumer test, in the original the consumer blocks
and only acks when all the messages in the queue have expired. So it will have
received 600 (prefetch) messages and they will be in the
prefetchsubscription.dispatched list on the broker. The test verifies that all
of these messages expire.
The variation of that test to validate this issue adds another batch of
messages with no expiry and validates that the consumer can receive them, so it
proves that expiring messages in the dispatched list does not block the
consumer.
Could you look at the test case to see if any of the options used in the test
do not match your use case?
> Slow consumer stops receiving messages because
> PrefetchSubscription.dispatched is filled with expired messages.
> ---------------------------------------------------------------------------------------------------------------
>
> Key: AMQ-2908
> URL: https://issues.apache.org/activemq/browse/AMQ-2908
> Project: ActiveMQ
> Issue Type: Bug
> Components: Broker
> Affects Versions: 5.3.2
> Reporter: Siim Kaalep
> Assignee: Gary Tully
>
> Slow consumer gets stuck when consuming from queue that has expiring messages
> in it.
> Looked into broker while it got stuck and saw that
> PrefetchSubscription.dispatched is full of expired messages.
> WORKAROUND
> Into doActualDispatch added check that if subscription is full, it will
> remove all expired message from dispatch.
> {code}
> Index:
> trunk/activemq-core/src/main/java/org/apache/activemq/broker/region/PrefetchSubscription.java
> ===================================================================
> ---
> trunk/activemq-core/src/main/java/org/apache/activemq/broker/region/PrefetchSubscription.java
> (revision 42304)
> +++
> trunk/activemq-core/src/main/java/org/apache/activemq/broker/region/PrefetchSubscription.java
> (working copy)
> @@ -400,6 +400,21 @@
> }
> }
>
> + public void removeExpiredMessagesFromDispatch() {
> + synchronized(dispatchLock) {
> + for (Iterator<MessageReference> iter =
> dispatched.iterator(); iter.hasNext(); ) {
> + final MessageReference node = iter.next();
> + if (node.isExpired()) {
> + if (broker.isExpired(node)) {
> +
> node.getRegionDestination().messageExpired(context, this, node);
> + }
> + dispatched.remove(node);
> +
> node.getRegionDestination().getDestinationStatistics().getInflight().decrement();
> + }
> + }
> + }
> + }
> +
> /**
> * Checks an ack versus the contents of the dispatched list.
> *
> {code}
> {code}
> Index:
> trunk/activemq-core/src/main/java/org/apache/activemq/broker/region/Queue.java
> ===================================================================
> ---
> trunk/activemq-core/src/main/java/org/apache/activemq/broker/region/Queue.java
> (revision 42304)
> +++
> trunk/activemq-core/src/main/java/org/apache/activemq/broker/region/Queue.java
> (working copy)
> @@ -1543,6 +1543,9 @@
> }
> if (dispatchSelector.canSelect(s, node)) {
> if (!fullConsumers.contains(s)) {
> + if (s.isFull() && s instanceof
> PrefetchSubscription) {
> +
> ((PrefetchSubscription)s).removeExpiredMessagesFromDispatch();
> + }
> if (!s.isFull()) {
> // Dispatch it.
> s.add(node);
> {code}
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