6.2. Using Job Charts

If you are tracking a Hive or Pig query that has been broken down into multiple interdependent jobs, you can use the Job Charts screen to see a more complete picture. The DAG tab displays a Directed Acyclic Graph (DAG) for the set of interdependent jobs and the Timeline & Tasks tab displays Timeline and Tasks information related to maps + reduces for each job in the set.

For example let’s use the entry for a Pig script named “wordcount” as an example.

From the job row overview description, we can see that the Pig script executed in three (3) interdependent jobs and required a total execution time of 105.01 seconds. This is the execution time for each job plus time for submitting and launching each job.

Now click on the job. The DAG/Charts screen pops up.

The DAG displays the execution sequence of each interdependent job as well as other information, including the duration of execution, I/O, and number of Map/Reduce tasks. The jobs are shown in a "swimlane" format, with the X-axis displaying the overall execution time, starting at 0 and increasing to 1m 45 seconds on the far right.


Pig scripts that include an “exec” call will break the script into multiple scripts (and subsequently, the interdependent jobs for those scripts). This causes the DAG to only show the jobs for the first script of the multiple scripts.

Click on the Timeline & Tasks tab to view the Job Timeline and Job Tasks graphs. These graphs show timing information for each task executed as part of a job. The Y-axis of the Job Timeline graph shows the number of tasks executed while the Y-axis on the Jobs Tasks graph shows the task runtime. Both graphs show the job timeline on the X-axis. Hover over the X-axis on the Job Timeline chart to see the absolute date + time in GMT.

These graphs represent a job in the “wordcount” example shown above. The Job Timeline graph shows a job execution time of 29 seconds total. A single map task started around 11 seconds after launch and ran for 4 seconds. Then a shuffle task ran for about 9 seconds and finished with a reduce task for 1 second.

The Job Tasks graph also shows the job execution time on the X-axis but on the Y-axis shows run time (in seconds). When the map and reduce tasks executed and their run-time (4 seconds and 11 seconds respectively) are shown on the Y-axis. Hover on each task circle and see more details, such as Wait-time and I/O. The size of the circle shown is based on the amount of I/O for the task. For map tasks, the color of the circle indicates whether the map task ran Node Local, Rack Local or Off Switch.

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