the app - usually the dbs become the bottleneck - resort to pre-computes for performance increasing complexity data shipping function shipping - data locality - low latency - high performance - low network transfer - modern big-data compute systems - Hadoop MR - Spark - Storm
Provides generic computing framework with UDF support - Datastores provides Hadoop integrations - Optimized for Batch processing but hardly for serving online content - Lot of operational overhead - And still no data locality :( real world aggregations