yingdachen commented on a change in pull request #37: TEZ-4042: Speculative
attempts should avoid running on the same node
URL: https://github.com/apache/tez/pull/37#discussion_r258243458
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File path: tez-dag/src/main/java/org/apache/tez/dag/app/dag/impl/TaskImpl.java
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@@ -1009,14 +1014,18 @@ public TaskStateInternal transition(TaskImpl task,
TaskEvent event) {
public void transition(TaskImpl task, TaskEvent event) {
LOG.info("Scheduling a redundant attempt for task " + task.taskId);
task.counters.findCounter(TaskCounter.NUM_SPECULATIONS).increment(1);
- TezTaskAttemptID earliestUnfinishedAttempt = null;
+ TaskAttempt earliestUnfinishedAttempt = null;
for (TaskAttempt ta : task.attempts.values()) {
// find the oldest running attempt
if (!ta.isFinished()) {
- earliestUnfinishedAttempt = ta.getID();
+ earliestUnfinishedAttempt = ta;
}
}
- task.addAndScheduleAttempt(earliestUnfinishedAttempt);
+ NodeId nodeId = earliestUnfinishedAttempt.getNodeId();
+ task.unhealthyNodesHistory.add(nodeId);
Review comment:
a piece of thought for discussions: in the loop above (line 1018-1021),
should we put the node id of ALL running attempts here into unhealthy nodes
(instead of just the earliest attempt)? since by the time we got here, a
redundant attempt was deemed necessary, that must be suggesting all the
unfinished(running) attempts for this task are potentially
problematic/long-tailed.
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