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https://issues.apache.org/jira/browse/TEZ-3696?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Eric Badger updated TEZ-3696:
-----------------------------
Attachment: TEZ-3696.002.patch
Putting up a new patch with 2 new unit tests. 1 tests to make sure that we send
a TA_COMPLETED event for all task attempts that get completed, not just
attempts that happen if the task hasn't succeeded yet. The other test makes
sure that we don't schedule new tasks if the attempt that sent the TA_COMPLETED
event wasn't running.
> Jobs can hang when both concurrency and speculation are enabled
> ---------------------------------------------------------------
>
> Key: TEZ-3696
> URL: https://issues.apache.org/jira/browse/TEZ-3696
> Project: Apache Tez
> Issue Type: Bug
> Reporter: Eric Badger
> Assignee: Eric Badger
> Attachments: TEZ-3696.001.patch, TEZ-3696.002.patch
>
>
> We can reproduce the hung job by doing the following:
> 1. Run a sleep job with a concurrency of 1, speculation enabled, and 3 tasks
> {noformat}
> HADOOP_CLASSPATH="$TEZ_HOME/*:$TEZ_HOME/lib/*:$TEZ_CONF_DIR" yarn jar
> $TEZ_HOME/tez-tests-*.jar mrrsleep -Dtez.am.vertex.max-task-concurrency=1
> -Dtez.am.speculation.enabled=true -Dtez.task.timeout-ms=60000 -m 3 -mt 60000
> -ir 0 -irt 0 -r 0 -rt 0
> {noformat}
> 2. Let the 1st task run to completion and then stop the 2nd task so that a
> speculative attempt is scheduled. Once the speculative attempt is scheduled
> for the 2nd task, continue the original attempt and let it complete.
> {noformat}
> kill -STOP <pid>
> // wait a few seconds for a speculative attempt to kick off
> kill -CONT <pid>
> {noformat}
> 3. Kill the 3rd task, which will create a 2nd attempt
> {noformat}
> kill -9 <pid>
> {noformat}
> 4. The next thing to be drawn off of the queue will be the speculative
> attempt of the 2nd task. However, it is already completed, so it will just
> sit in the final state and the job will hang.
> Basically, for the failure to happen, the number of speculative tasks that
> are scheduled, but not yet ran has to be >= the concurrency of the job and
> there has to be at least 1 task failure.
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