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https://issues.apache.org/jira/browse/AMQ-4683?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13748658#comment-13748658
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Timothy Bish commented on AMQ-4683:
-----------------------------------
Case 1 analysis is incorrect.
Case 2 is true although the broker implementation doesn't currently use more
than one listener so it wouldn't happen this way.
I've made some changes to make the start of dispatching separate from starting
the store. Now the start of dispatch occurs when the SchedulerBroker is
started and is stopped when its stopped. Any listener added after the broker
could miss jobs but that's an inherent trait in any event based model.
> Scheduler discards overdue messages on startup
> ----------------------------------------------
>
> Key: AMQ-4683
> URL: https://issues.apache.org/jira/browse/AMQ-4683
> Project: ActiveMQ
> Issue Type: Bug
> Components: Broker
> Affects Versions: 5.8.0
> Environment: Windows 7 64bit, JDK 1.6.0_26
> Reporter: Andrey Zavodnik
> Assignee: Timothy Bish
> Priority: Critical
> Labels: scheduler
> Fix For: 5.9.0
>
> Attachments: LostScheduledMessagesTest.java
>
>
> When message is scheduled for a delivery (using AMQ_SCHEDULED_PERIOD
> property) it is not posted to the queue, but saved to the scheduler’s
> repository instead. If Broker instance is shut down at the time for which the
> message is scheduled for a delivery, the scheduler will try to process the
> message at the next time broker is started up. Due to a bug in the scheduler
> implementation such messages may be dismissed rather than posted to the queue
> depending on the racing conditions inside the JVM.
> Actual bug resides in
> org.apache.activemq.broker.scheduler.SchedulerBroker.getInternalScheduler()
> method.
> This method first calls JobSchedulerStoreImpl. getJobScheduler(String name)
> method which in turn creates an instance of runnable JobSchedulerImpl class
> and starts it.
> Then SchedulerBroker registers itselfas a listener of the newly created
> JobSchedulerImpl.
> Unfortunately this may happen after the JobSchedulerImpl have dismissed all
> the “missed” tasks as “fired” as there were no listeners configured.
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