6. Troubleshooting

View the Tez logs to help troubleshoot problems with your installation and configuration. Tez logs are accessible through the YARN CLI using the yarn logs command.

yarn logs -applicationId <APPLICATION_ID> [OPTIONS]

You can find the application ID at the end of the output to a running application, as shown in the following output from the OrderedWordCount application.

14/02/26 14:45:33 INFO examples.OrderedWordCount: DAG 1 completed. FinalState=SUCCEEDED
14/02/26 14:45:33 INFO client.TezSession: Shutting down Tez Session, sessionName=OrderedWordCountSession, applicationId=application_1393449467938_0001

Apache Tez is still maturing as a technology, and there is not yet complete feature parity between it and Apache MapReduce. Try the following troubleshooting techniques if a Tez-based application does not run successfully.

  • Does the application run successfully with Query Vectorization turned off?

  • Does the application run successfully with Tez in a different session?

  • Does the application run successfully with MapReduce?

    Include all configuration settings and the answers to the above three questions with your support call. Providing Hortonworks Technical Support with the Tez configuration settings used for a problematic query is critical. The same query run with both the Tez and MapReduce execution engines should return the same results.

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