[
https://issues.apache.org/jira/browse/AMQ-6579?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15838010#comment-15838010
]
Christopher L. Shannon commented on AMQ-6579:
---------------------------------------------
Good catch, this is indeed a bug and the fix you suggest is correct. The
dispatched counter should only increment when messages are added to the
dispatched list and not expired.
> Expired messages counting as Dispatched on TopicSubscription
> ------------------------------------------------------------
>
> Key: AMQ-6579
> URL: https://issues.apache.org/jira/browse/AMQ-6579
> Project: ActiveMQ
> Issue Type: Bug
> Affects Versions: 5.15.0, 5.14.3
> Reporter: Vasco Veloso
> Assignee: Christopher L. Shannon
>
> When a TopicSubscription is configured with a limit on the number of pending
> messages, it will try to eagerly evict expired messages before dispatching
> them.
> {code:title=TopicSubscription.java:169}
> if (!matched.isEmpty() && matched.size() > max) {
> removeExpiredMessages();
> }
> {code}
> When {{TopicSubscription#removeExpiredMessages}} detects an expired message,
> it will remove it but will increment the counter of dispatched messages as
> well.
> {code:title=TopicSubscription.java:235}
> if (node.isExpired()) {
> matched.remove();
> getSubscriptionStatistics().getDispatched().increment();
> node.decrementReferenceCount();
> if (broker.isExpired(node)) {
> ((Destination)
> node.getRegionDestination()).getDestinationStatistics().getExpired().increment();
> broker.messageExpired(getContext(), node, this);
> }
> break;
> }
> {code}
> However this has the side effect of affecting the result of
> {{getDispatchedQueueSize()}} and therefore {{isFull()}}. These counters will
> now reflect a new dispatched message that has actually been dropped.
> In the worst case scenario slow consumers will no longer receive messages
> because they are "full" when in fact they have nothing to process.
> Am I correct in concluding that expired messages must not count towards the
> dispatched value?
> I have made a quick change, removing the increment, and things look good so
> far. However I am worried that I may be missing some side effect or
> specification detail.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
