AWS EMR Big Data

AWS EMR (Elastic MapReduce) is a managed cluster service for distributed data processing. You specify cluster size, choose frameworks (Spark, Hadoop, Presto, Hive), submit jobs, and EMR handles scheduling across worker nodes. Data lives on S3; clusters process it in parallel; results go back to S3. EMR is for processing terabytes to petabytes of data. For smaller datasets, Athena is simpler.