In one exemplary embodiment, a method of a distributed database system includes the step receiving a query in a query language from a client with a distributed database system. An index that matches the query is located. The index is pre-generated from a database table in the distributed database system. A map function of a MapReduce programming model is implemented using the index. A reduce function of the MapReduce programming model is implemented using the output of the map function. Optionally, a finalize function can be implemented using the output of the reduce function. The distributed database system can be a scalable NoSQL database. The reduce function can be optional when the value of the output of the map function is guaranteed to be unique.