Archives of Support Questions (Read Only)

This is an archived board for historical reference. Information and links may no longer be available or relevant
Announcements
This board is archived and read-only for historical reference. To ask a new question, please post a new topic on the appropriate active board.

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