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https://issues.apache.org/jira/browse/TEZ-3974?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16569016#comment-16569016
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TezQA commented on TEZ-3974:
----------------------------
{color:red}-1 overall{color}. Here are the results of testing the latest
attachment
http://issues.apache.org/jira/secure/attachment/12934359/TEZ-3974.1.patch
against master revision fe22f32.
{color:green}+1 @author{color}. The patch does not contain any @author
tags.
{color:red}-1 tests included{color}. The patch doesn't appear to include
any new or modified tests.
Please justify why no new tests are needed for this
patch.
Also please list what manual steps were performed to
verify this patch.
{color:green}+1 javac{color}. The applied patch does not increase the
total number of javac compiler warnings.
{color:green}+1 javadoc{color}. There were no new javadoc warning messages.
{color:green}+1 findbugs{color}. The patch does not introduce any new
Findbugs (version 3.0.1) warnings.
{color:green}+1 release audit{color}. The applied patch does not increase
the total number of release audit warnings.
{color:green}+1 core tests{color}. The patch passed unit tests in .
Test results:
https://builds.apache.org/job/PreCommit-TEZ-Build/2886//testReport/
Console output: https://builds.apache.org/job/PreCommit-TEZ-Build/2886//console
This message is automatically generated.
> Tez: Correctness regression of TEZ-955 in TEZ-2937
> --------------------------------------------------
>
> Key: TEZ-3974
> URL: https://issues.apache.org/jira/browse/TEZ-3974
> Project: Apache Tez
> Issue Type: Bug
> Reporter: Gopal V
> Assignee: Jaume M
> Priority: Critical
> Attachments: TEZ-3974.1.patch
>
>
> TEZ-2937 might have introduced a race condition for Tez output events, along
> with TEZ-2237
> {code}
> // Close the Outputs.
> for (OutputSpec outputSpec : outputSpecs) {
> String destVertexName = outputSpec.getDestinationVertexName();
> initializedOutputs.remove(destVertexName);
> List<Event> closeOutputEvents =
> ((LogicalOutputFrameworkInterface)outputsMap.get(destVertexName)).close();
> sendTaskGeneratedEvents(closeOutputEvents,
> EventProducerConsumerType.OUTPUT, taskSpec.getVertexName(),
> destVertexName, taskSpec.getTaskAttemptID());
> }
> // Close the Processor.
> processorClosed = true;
> processor.close();
> {code}
> As part of TEZ-2237, the outputs send empty events when the output is closed
> without being started (which happens in task init failures).
> These events are obsoleted when a task fails and this happens in the AM, but
> not before the dispatcher looks at them.
> Depending on the timing, the empty events can escape obsoletion & be sent to
> a downstream task.
> This gets marked as a SKIPPED event in the downstream task, which means that
> further obsoletion events sent to the downstream task is ignored (because a
> zero byte fetch is not repeated on node failure).
> So the downstream task can exit without actually waiting for the retry of the
> failed task and cause silent dataloss in case where the retry succeeds in
> another attempt.
> So if processor.close() throws an exception, this introduce a race condition
> and if the AM is too fast, we end up with correctness issues.
> This was originally reported in TEZ-955
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