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Identify number of Mappers & Reducers launched in a Pig script

avatar
New Member

I'm using Hortonworks' sandbox VM to run Hadoop services. I executed a Pig filter script in Tez mode. Unlike Hive, the Pig log (console) doesn't show any information about the number of mappers & reducers being executed. Am I looking at a wrong place?

1 ACCEPTED SOLUTION

avatar
Guru

For tez "tasks" represent map operations or reduce operations. A DAG is a full workflow (job) of vertices (processing of tasks) and edges (data movement between vertices).

See these links for a more detailed discussion:

http://hortonworks.com/blog/expressing-data-processing-in-apache-tez/

https://community.hortonworks.com/questions/32164/question-on-tez-dag-task-and-pig-on-tez.html

https://cwiki.apache.org/confluence/display/TEZ/How+initial+task+parallelism+works

You can see number of tasks on the console output:

9365-screen-shot-2016-11-11-at-95327-am.png

You can also see this in Ambari Tez view (and drill down for greater details)

See this for understanding Ambari Tez view: https://docs.hortonworks.com/HDPDocuments/Ambari-2.1.2.0/bk_ambari_views_guide/content/section_using...

9366-screen-shot-2016-11-11-at-95511-am.png


screen-shot-2016-11-11-at-91936-am.pngscreen-shot-2016-11-11-at-92701-am.pngscreen-shot-2016-11-11-at-91601-am.png

View solution in original post

3 REPLIES 3

avatar
Guru

@Dhiwa TdG

If you verified your output for Hive via Hive/Beeline shell, then its a different story, you are actually seeing the output on STDOUT. With Pig, you can try using pig view instead.

Ambari -> admin (drop down) -> Manage Ambari -> Views -> PIG -> Create Instance (If you don't have a PIG view already)

avatar
New Member

Thank your for your response but I had done that already. I executed the Pig script both via terminal (pig -x tez script.pig)& from Ambari/Pig view. Also when I expanded the logs section in Pig view it was very similar too the one which I had in terminal (console). I don't see any mappers nor reducer counts. 😞

avatar
Guru

For tez "tasks" represent map operations or reduce operations. A DAG is a full workflow (job) of vertices (processing of tasks) and edges (data movement between vertices).

See these links for a more detailed discussion:

http://hortonworks.com/blog/expressing-data-processing-in-apache-tez/

https://community.hortonworks.com/questions/32164/question-on-tez-dag-task-and-pig-on-tez.html

https://cwiki.apache.org/confluence/display/TEZ/How+initial+task+parallelism+works

You can see number of tasks on the console output:

9365-screen-shot-2016-11-11-at-95327-am.png

You can also see this in Ambari Tez view (and drill down for greater details)

See this for understanding Ambari Tez view: https://docs.hortonworks.com/HDPDocuments/Ambari-2.1.2.0/bk_ambari_views_guide/content/section_using...

9366-screen-shot-2016-11-11-at-95511-am.png


screen-shot-2016-11-11-at-91936-am.pngscreen-shot-2016-11-11-at-92701-am.pngscreen-shot-2016-11-11-at-91601-am.png