# Temporal Workflow failing

**URL:** <https://community.temporal.io/t/temporal-workflow-failing/9187>\
**Category:** Community Support\
**Tags:** java-sdk\
**Created:** [August 15, 2023, 11:29am UTC](https://community.temporal.io/t/temporal-workflow-failing/9187 "2023-08-15T11:29:57Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![Anjula\_Paulus](https://sea2.discourse-cdn.com/flex016/user_avatar/community.temporal.io/anjula_paulus/32/1715_2.png) [@Anjula\_Paulus](https://community.temporal.io/u/Anjula_Paulus)\
**Post date:** [August 15, 2023, 11:29am UTC](https://community.temporal.io/t/temporal-workflow-failing/9187/1 "2023-08-15T11:29:58Z")

</div>

The workflow task fails due to the following error.

```auto
{
  "message": "java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.FutureTask@669ab3b5[Not completed, task = java.util.concurrent.Executors$RunnableAdapter@4b1c6cb0[Wrapped task = io.temporal.worker.ActiveThreadReportingExecutor$$Lambda$1585/0x00007fe1dba33818@6be7fe0a]] rejected from java.util.concurrent.ThreadPoolExecutor@14c45dad[Running, pool size = 10, active threads = 10, queued tasks = 0, completed tasks = 348]",
  "source": "JavaSDK",
  "stackTrace": "io.temporal.internal.sync.WorkflowThreadImpl.start(WorkflowThreadImpl.java:247)\nio.temporal.internal.sync.WorkflowThreadImpl.runUntilBlocked(WorkflowThreadImpl.java:299)\nio.temporal.internal.sync.DeterministicRunnerImpl.runUntilAllBlocked(DeterministicRunnerImpl.java:229)\nio.temporal.internal.sync.SyncWorkflow.eventLoop(SyncWorkflow.java:147)\nio.temporal.internal.replay.ReplayWorkflowExecutor.eventLoop(ReplayWorkflowExecutor.java:67)\nio.temporal.internal.replay.ReplayWorkflowRunTaskHandler$StatesMachinesCallbackImpl.eventLoop(ReplayWorkflowRunTaskHandler.java:360)\nio.temporal.internal.statemachines.WorkflowStateMachines.eventLoop(WorkflowStateMachines.java:490)\nio.temporal.internal.statemachines.WorkflowStateMachines.access$500(WorkflowStateMachines.java:56)\nio.temporal.internal.statemachines.WorkflowStateMachines$WorkflowTaskCommandsListener.workflowTaskStarted(WorkflowStateMachines.java:954)\nio.temporal.internal.statemachines.WorkflowTaskStateMachine.handleCompleted(WorkflowTaskStateMachine.java:127)\nio.temporal.internal.statemachines.WorkflowTaskStateMachine.handleStarted(WorkflowTaskStateMachine.java:117)\nio.temporal.internal.statemachines.FixedTransitionAction.apply(FixedTransitionAction.java:46)\nio.temporal.internal.statemachines.StateMachine.executeTransition(StateMachine.java:148)\nio.temporal.internal.statemachines.StateMachine.handleHistoryEvent(StateMachine.java:102)\nio.temporal.internal.statemachines.EntityStateMachineBase.handleEvent(EntityStateMachineBase.java:68)\nio.temporal.internal.statemachines.WorkflowStateMachines.handleSingleEvent(WorkflowStateMachines.java:277)\nio.temporal.internal.statemachines.WorkflowStateMachines.handleEventsBatch(WorkflowStateMachines.java:234)\nio.temporal.internal.statemachines.WorkflowStateMachines.handleEvent(WorkflowStateMachines.java:208)\nio.temporal.internal.replay.ReplayWorkflowRunTaskHandler.applyServerHistory(ReplayWorkflowRunTaskHandler.java:224)\nio.temporal.internal.replay.ReplayWorkflowRunTaskHandler.handleWorkflowTaskImpl(ReplayWorkflowRunTaskHandler.java:208)\nio.temporal.internal.replay.ReplayWorkflowRunTaskHandler.handleWorkflowTask(ReplayWorkflowRunTaskHandler.java:156)\nio.temporal.internal.replay.ReplayWorkflowTaskHandler.handleWorkflowTaskWithQuery(ReplayWorkflowTaskHandler.java:131)\nio.temporal.internal.replay.ReplayWorkflowTaskHandler.handleWorkflowTask(ReplayWorkflowTaskHandler.java:96)\nio.temporal.internal.worker.WorkflowWorker$TaskHandlerImpl.handleTask(WorkflowWorker.java:407)\nio.temporal.internal.worker.WorkflowWorker$TaskHandlerImpl.handle(WorkflowWorker.java:317)\nio.temporal.internal.worker.WorkflowWorker$TaskHandlerImpl.handle(WorkflowWorker.java:259)\nio.temporal.internal.worker.PollTaskExecutor.lambda$process$0(PollTaskExecutor.java:105)\njava.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)\njava.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)\njava.base/java.lang.Thread.run(Unknown Source)\n",
  "encodedAttributes": null,
  "cause": {
    "message": "Task java.util.concurrent.FutureTask@669ab3b5[Not completed, task = java.util.concurrent.Executors$RunnableAdapter@4b1c6cb0[Wrapped task = io.temporal.worker.ActiveThreadReportingExecutor$$Lambda$1585/0x00007fe1dba33818@6be7fe0a]] rejected from java.util.concurrent.ThreadPoolExecutor@14c45dad[Running, pool size = 10, active threads = 10, queued tasks = 0, completed tasks = 348]",
    "source": "JavaSDK",
    "stackTrace": "java.base/java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(Unknown Source)\njava.base/java.util.concurrent.ThreadPoolExecutor.reject(Unknown Source)\njava.base/java.util.concurrent.ThreadPoolExecutor.execute(Unknown Source)\njava.base/java.util.concurrent.AbstractExecutorService.submit(Unknown Source)\nio.temporal.worker.ActiveThreadReportingExecutor.submit(ActiveThreadReportingExecutor.java:48)\nio.temporal.internal.sync.WorkflowThreadImpl.start(WorkflowThreadImpl.java:234)\nio.temporal.internal.sync.WorkflowThreadImpl.runUntilBlocked(WorkflowThreadImpl.java:299)\nio.temporal.internal.sync.DeterministicRunnerImpl.runUntilAllBlocked(DeterministicRunnerImpl.java:229)\nio.temporal.internal.sync.SyncWorkflow.eventLoop(SyncWorkflow.java:147)\nio.temporal.internal.replay.ReplayWorkflowExecutor.eventLoop(ReplayWorkflowExecutor.java:67)\nio.temporal.internal.replay.ReplayWorkflowRunTaskHandler$StatesMachinesCallbackImpl.eventLoop(ReplayWorkflowRunTaskHandler.java:360)\nio.temporal.internal.statemachines.WorkflowStateMachines.eventLoop(WorkflowStateMachines.java:490)\nio.temporal.internal.statemachines.WorkflowStateMachines.access$500(WorkflowStateMachines.java:56)\nio.temporal.internal.statemachines.WorkflowStateMachines$WorkflowTaskCommandsListener.workflowTaskStarted(WorkflowStateMachines.java:954)\nio.temporal.internal.statemachines.WorkflowTaskStateMachine.handleCompleted(WorkflowTaskStateMachine.java:127)\nio.temporal.internal.statemachines.WorkflowTaskStateMachine.handleStarted(WorkflowTaskStateMachine.java:117)\nio.temporal.internal.statemachines.FixedTransitionAction.apply(FixedTransitionAction.java:46)\nio.temporal.internal.statemachines.StateMachine.executeTransition(StateMachine.java:148)\nio.temporal.internal.statemachines.StateMachine.handleHistoryEvent(StateMachine.java:102)\nio.temporal.internal.statemachines.EntityStateMachineBase.handleEvent(EntityStateMachineBase.java:68)\nio.temporal.internal.statemachines.WorkflowStateMachines.handleSingleEvent(WorkflowStateMachines.java:277)\nio.temporal.internal.statemachines.WorkflowStateMachines.handleEventsBatch(WorkflowStateMachines.java:234)\nio.temporal.internal.statemachines.WorkflowStateMachines.handleEvent(WorkflowStateMachines.java:208)\nio.temporal.internal.replay.ReplayWorkflowRunTaskHandler.applyServerHistory(ReplayWorkflowRunTaskHandler.java:224)\nio.temporal.internal.replay.ReplayWorkflowRunTaskHandler.handleWorkflowTaskImpl(ReplayWorkflowRunTaskHandler.java:208)\nio.temporal.internal.replay.ReplayWorkflowRunTaskHandler.handleWorkflowTask(ReplayWorkflowRunTaskHandler.java:156)\nio.temporal.internal.replay.ReplayWorkflowTaskHandler.handleWorkflowTaskWithQuery(ReplayWorkflowTaskHandler.java:131)\nio.temporal.internal.replay.ReplayWorkflowTaskHandler.handleWorkflowTask(ReplayWorkflowTaskHandler.java:96)\nio.temporal.internal.worker.WorkflowWorker$TaskHandlerImpl.handleTask(WorkflowWorker.java:407)\nio.temporal.internal.worker.WorkflowWorker$TaskHandlerImpl.handle(WorkflowWorker.java:317)\nio.temporal.internal.worker.WorkflowWorker$TaskHandlerImpl.handle(WorkflowWorker.java:259)\nio.temporal.internal.worker.PollTaskExecutor.lambda$process$0(PollTaskExecutor.java:105)\njava.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)\njava.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)\njava.base/java.lang.Thread.run(Unknown Source)\n",
    "encodedAttributes": null,
    "cause": null,
    "applicationFailureInfo": {
      "type": "java.util.concurrent.RejectedExecutionException",
      "nonRetryable": false,
      "details": null
    }
  },
  "applicationFailureInfo": {
    "type": "io.temporal.internal.sync.WorkflowRejectedExecutionError",
    "nonRetryable": false,
    "details": null
  }
}

```

The reason seems to be not clear. Could someone help to figure this out?

Is it related to this configuration

```auto
    workflow-cache:
      max-instances: 10
      max-threads: 10

```

---

<div class="post-metadata">

**Author:** ![maxim](https://sea2.discourse-cdn.com/flex016/user_avatar/community.temporal.io/maxim/32/8_2.png) [@maxim](https://community.temporal.io/u/maxim)\
**Post date:** [August 15, 2023, 4:56pm UTC](https://community.temporal.io/t/temporal-workflow-failing/9187/2 "2023-08-15T16:56:39Z")

</div>

10 for workflow thread pool is very low as threads are needed for signals and other callbacks.

---

<div class="post-metadata">

**Author:** ![Anjula\_Paulus](https://sea2.discourse-cdn.com/flex016/user_avatar/community.temporal.io/anjula_paulus/32/1715_2.png) [@Anjula\_Paulus](https://community.temporal.io/u/Anjula_Paulus)\
**Post date:** [August 15, 2023, 5:14pm UTC](https://community.temporal.io/t/temporal-workflow-failing/9187/3 "2023-08-15T17:14:30Z")

</div>

What would be the ideal number of threads and what is defined here as max-instances?

---

<div class="post-metadata">

**Author:** ![maxim](https://sea2.discourse-cdn.com/flex016/user_avatar/community.temporal.io/maxim/32/8_2.png) [@maxim](https://community.temporal.io/u/maxim)\
**Post date:** [August 15, 2023, 5:16pm UTC](https://community.temporal.io/t/temporal-workflow-failing/9187/4 "2023-08-15T17:16:15Z")

</div>

It depends on the number of threads each workflow needs to execute. The ideal number would be the number of threads per workflow multiplied by the number of parallel workflow tasks being executed, plus threads used by cached workflows.