PotentialDeadlockException, when does this happen?

Hi,

While experimenting. I get this error

io.temporal.internal.replay.InternalWorkflowTaskException: Failure handling event 3 of 'EVENT_TYPE_WORKFLOW_TASK_STARTED' type. IsReplaying=false, PreviousStartedEventId=3, workflowTaskStartedEventId=3, Currently Processing StartedEventId=3 
io.temporal.internal.statemachines.WorkflowStateMachines.handleEvent(WorkflowStateMachines.java:193)
io.temporal.internal.replay.ReplayWorkflowRunTaskHandler.handleEvent(ReplayWorkflowRunTaskHandler.java:140)
io.temporal.internal.replay.ReplayWorkflowRunTaskHandler.handleWorkflowTaskImpl(ReplayWorkflowRunTaskHandler.java:180)
io.temporal.internal.replay.ReplayWorkflowRunTaskHandler.handleWorkflowTask(ReplayWorkflowRunTaskHandler.java:150)
io.temporal.internal.replay.ReplayWorkflowTaskHandler.handleWorkflowTaskWithEmbeddedQuery(ReplayWorkflowTaskHandler.java:201)
io.temporal.internal.replay.ReplayWorkflowTaskHandler.handleWorkflowTask(ReplayWorkflowTaskHandler.java:114)
io.temporal.internal.worker.WorkflowWorker$TaskHandlerImpl.handle(WorkflowWorker.java:319)
io.temporal.internal.worker.WorkflowWorker$TaskHandlerImpl.handle(WorkflowWorker.java:279)
io.temporal.internal.worker.PollTaskExecutor.lambda$process$0(PollTaskExecutor.java:73)
java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
java.base/java.lang.Thread.run(Thread.java:834)

Caused By: java.lang.RuntimeException: WorkflowTask: failure executing SCHEDULED->WORKFLOW_TASK_STARTED, transition history is [CREATED->WORKFLOW_TASK_SCHEDULED] 
io.temporal.internal.statemachines.StateMachine.executeTransition(StateMachine.java:140)
io.temporal.internal.statemachines.StateMachine.handleHistoryEvent(StateMachine.java:91)
io.temporal.internal.statemachines.EntityStateMachineBase.handleEvent(EntityStateMachineBase.java:63)
io.temporal.internal.statemachines.WorkflowStateMachines.handleEventImpl(WorkflowStateMachines.java:210)
io.temporal.internal.statemachines.WorkflowStateMachines.handleEvent(WorkflowStateMachines.java:178)
io.temporal.internal.replay.ReplayWorkflowRunTaskHandler.handleEvent(ReplayWorkflowRunTaskHandler.java:140)
io.temporal.internal.replay.ReplayWorkflowRunTaskHandler.handleWorkflowTaskImpl(ReplayWorkflowRunTaskHandler.java:180)
io.temporal.internal.replay.ReplayWorkflowRunTaskHandler.handleWorkflowTask(ReplayWorkflowRunTaskHandler.java:150)
io.temporal.internal.replay.ReplayWorkflowTaskHandler.handleWorkflowTaskWithEmbeddedQuery(ReplayWorkflowTaskHandler.java:201)
io.temporal.internal.replay.ReplayWorkflowTaskHandler.handleWorkflowTask(ReplayWorkflowTaskHandler.java:114)
io.temporal.internal.worker.WorkflowWorker$TaskHandlerImpl.handle(WorkflowWorker.java:319)
io.temporal.internal.worker.WorkflowWorker$TaskHandlerImpl.handle(WorkflowWorker.java:279)
io.temporal.internal.worker.PollTaskExecutor.lambda$process$0(PollTaskExecutor.java:73)
java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
java.base/java.lang.Thread.run(Thread.java:834)

Caused By: io.temporal.internal.sync.PotentialDeadlockException: Potential deadlock detected: workflow thread "workflow-method" didn't yield control for over a second. Other workflow 

The flow goes so

Kafkaevent stream → calls a funcion → calls a workflow → calls an activity

I am a bit lost on debugging this. any help

Are you getting this error during debugging?

For debugging please set the TEMPORAL_DEBUG env variable to true – https://docs.temporal.io/docs/java/testing-and-debugging

If not, could you share your workflow code (or parts of it?). Could be that you are not using the dedicated workflow sleep methods (Workflow.sleep) or have some other type of non-deterministic problems.

Hope this helps.

thank you. that was it. I just had to set TEMPORAL_DEBUG :slight_smile:

Make sure to set it only when you plan to put breakpoints into the workflow code. Any other use might obscure real serious problems with the workflow code.

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