Race condition if timers overlap due to long running execution and short schedules if database persistence is used ------------------------------------------------------------------------------------------------------------------ Key: WFLY-8929 URL: https://issues.jboss.org/browse/WFLY-8929 Project: WildFly Issue Type: Bug Components: EJB Environment: Configure DB persistence for timers as file-persistence will not have a persistence check for shouldRun to lock the timer execution. Reporter: Wolf-Dieter Fink Attachments: server-extract.log If timers (here calendar timer) are running longer than scheduled, or the schedule/processing get stuck do to thread or cpu bottleneck, it is possible that the updates for persistence overlap. The issue seems that the task(1) try to finish the timer and task(2) is about to start but see the concurrency. The DB is updated with the 'old' next timeout, but the internal Timer instance will be updated with the next possible schedule due to a race condition between the two threads updating the object.