Select Map Contents.
I created a HBase table from Hive and I'm trying to do a simple aggregation on it. This is my Hive query: from myhbasetableselect col1, count(1)group by col1;The map reduce job spawns only 2 mappers and I'd like to increase that. With a plain map reduce job I would configure the yarn and mapper memory to increase the number of mappers. I tried the following in Hive but it did not work: set yarn.nodemanager.resource.cpu-vcores=16;set yarn.nodemanager.resource.memory-mb=32768;set mapreduce.map.cpu.vcores=1;set mapreduce.map.memory.mb=2048;NOTE:. My test cluster has only 2 nodes. The HBase table has more than 5M records. Hive logs show HiveInputFormat and a number of splits=2.
Split the file lesser then default value is not a efficient solution. Spiting is basically used during dealing with large dataset. Default value is itself a small size so its not worth to split it again.I would recommend following configuration before your query.You can apply it based upon your input data.