How to set input split settings?

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I have an object of the org.apache.hadoop.conf.Configuration class. I have a 20 GB file, and I want to fire 40 mappers. How can I do it?

Dec 27, 2018 in Big Data Hadoop by slayer
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1 answer to this question.

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It can be controlled by setting the parameters, mapred.min.split.size and mapred.max.split.size, while configuring the job in MapReduce. The value is to be set in bytes. So if we have a 20 GB file, and we want to fire 40 mappers, then we need to set it to 20480 / 40 = 512 MB each. So for that the code would be,
conf.set("mapred.min.split.size", "536870912"); 
conf.set("mapred.max.split.size", "536870912");

answered Dec 27, 2018 by Omkar
• 68,180 points

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