How to increase reducers in Hive

Question

Hello. I am running a MapReduce job in Hive and I want to increase the number of reducers because I think the process is slow. There's a query plan for this job and I want to increase the number of reducers for each stage. How can I do it?

Answer 1

By default, only one reducer is assigned for a job at each stage. If you want to increase this, you can mention the number of reducers along with the hive command. Refer to the below command:

$ hive --hiveconf mapred.reduce.tasks=<number of reducers>