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Add extra diagnostics to pinpoint issue with missing spoolingOutputStats #22170

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Merged
losipiuk merged 4 commits into from
May 28, 2024
Merged

Add extra diagnostics to pinpoint issue with missing spoolingOutputStats #22170

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e16f4a9
Add sanity checks
losipiuk May 28, 2024
78b6888
Relax log condition
losipiuk May 28, 2024
412900f
Log full task info when unexpected missing spoolingOutputStats
losipiuk May 28, 2024
7de50e4
Add extra diagnostics to pinpoint issue with missing spoolingOutputStats
losipiuk May 28, 2024
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4 changes: 2 additions & 2 deletions ...va/io/trino/execution/scheduler/faulttolerant/EventDrivenFaultTolerantQueryScheduler.java
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Original file line number Diff line number Diff line change
Expand Up @@ -2805,9 +2805,9 @@ public void addTask(RemoteTask remoteTask, SpoolingOutputBuffers outputBuffers,
public SpoolingOutputStats.Snapshot taskFinished(TaskId taskId)
{
RemoteTask remoteTask = tasks.get(taskId);
checkState(runningTasks.remove(taskId), "task %s already marked as finished", taskId);
checkArgument(remoteTask != null, "task not found: %s", taskId);
SpoolingOutputStats.Snapshot outputStats = remoteTask.retrieveAndDropSpoolingOutputStats();
runningTasks.remove(taskId);
tasks.values().forEach(RemoteTask::abort);
finished = true;
// task descriptor has been created
Expand All @@ -2819,7 +2819,7 @@ public SpoolingOutputStats.Snapshot taskFinished(TaskId taskId)

public void taskFailed(TaskId taskId)
{
runningTasks.remove(taskId);
checkState(runningTasks.remove(taskId), "task %s already marked as finished", taskId);
failureObserved = true;
remainingAttempts--;
}
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13 changes: 10 additions & 3 deletions core/trino-main/src/main/java/io/trino/server/remotetask/TaskInfoFetcher.java
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Original file line number Diff line number Diff line change
Expand Up @@ -272,10 +272,14 @@ synchronized void updateTaskInfo(TaskInfo newTaskInfo)
newTaskInfo = newTaskInfo.withEstimatedMemory(estimatedMemory.get());
}

boolean missingSpoolingOutputStats = false;
if (newTaskInfo.taskStatus().getState().isDone()) {
boolean wasSet = spoolingOutputStats.compareAndSet(null, newTaskInfo.outputBuffers().getSpoolingOutputStats().orElse(null));
if (retryPolicy == TASK && wasSet && spoolingOutputStats.get() == null) {
log.debug("Task %s was updated to null spoolingOutputStats. Future calls to retrieveAndDropSpoolingOutputStats will fail.", taskId);
if (newTaskInfo.taskStatus().getState() == TaskState.FINISHED && retryPolicy == TASK && wasSet && spoolingOutputStats.get() == null) {
missingSpoolingOutputStats = true;
if (log.isDebugEnabled()) {
log.debug("Task %s was updated to null spoolingOutputStats. Future calls to retrieveAndDropSpoolingOutputStats will fail; taskInfo=%s", taskId, taskInfoCodec.toJson(newTaskInfo));
}
}
newTaskInfo = newTaskInfo.pruneSpoolingOutputStats();
}
Expand All @@ -294,7 +298,10 @@ synchronized void updateTaskInfo(TaskInfo newTaskInfo)

if (updated && newValue.taskStatus().getState().isDone()) {
taskStatusFetcher.updateTaskStatus(newTaskInfo.taskStatus());
finalTaskInfo.compareAndSet(Optional.empty(), Optional.of(newValue));
boolean finalTaskInfoUpdated = finalTaskInfo.compareAndSet(Optional.empty(), Optional.of(newValue));
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@dekimir dekimir Jun 1, 2024

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It seems to me that we should just refuse to update finalTaskInfo here if missingSpoolingOutputStats is true. Updating it will trigger the listener registered here:

trino/core/trino-main/src/main/java/io/trino/execution/scheduler/faulttolerant/EventDrivenFaultTolerantQueryScheduler.java

Line 1690 in 27e7863

task.addFinalTaskInfoListener(taskInfo -> eventQueue.add(new RemoteTaskCompletedEvent(taskInfo.taskStatus())));

which will eventually trigger this line:

trino/core/trino-main/src/main/java/io/trino/execution/scheduler/faulttolerant/EventDrivenFaultTolerantQueryScheduler.java

Line 2810 in 27e7863

SpoolingOutputStats.Snapshot outputStats = remoteTask.retrieveAndDropSpoolingOutputStats();

and that's forbidden when the spoolingOutputStats is missing.

Storing a null stats here guarantees that the null check will fail in retrieveAndDropSpoolingOutputStats().

if (missingSpoolingOutputStats && finalTaskInfoUpdated) {
log.debug("Updated finalTaskInfo for task %s to one with missing spoolingOutputStats", taskId);
}
stop();
}
}
Expand Down