I recently created an Ambari Cluster using the steps mentioned here - https://hortonworks.com/blog/deploying-hadoop-cluster-amazon-ec2-hortonworks/ Hive is working perfectly fine. However, the time taken by the Ambari cluster for query planing and launching Mappers or Reducers is very large in comparison to what an EMR cluster with same specifications takes. No mappers or reducers are launched during this process and their count is displayed as -1. After a lot of time is spent in query planning, Mappers and Reducers are launched and then the execution takes place. Is this kind of delay an expected behavior or are there things that can be tuned or modified to reduce the query planning time ? Any help would be appreciated.