Method and system of mapreduce implementations on indexed datasets in a distributed database environment

1. A method in a distributed database system, the distributed database system comprising a processor, the method comprising:

receiving a query in a query language from a client with a distributed database system;

locating an index that matches the query, wherein the index is pre-generated from a database table in the distributed database system;

implementing a map function of a MapReduce programming model using the index; and

implementing a reduce function of the Map Reduce programming model using the output of the map function.

2. The method of claim 1 further comprising:

implementing a finalize function using the output of the reduce function.

3. The method of claim 1 wherein the map function comprises:

obtaining a series of key/value pairs; and

processing each key/value pair to generate zero or more output key/value pairs.

4. The method of claim 1 , wherein the distributed database system comprises a scalable NoSQL database.

5. The method of claim 4 , wherein the NoSQL database is implemented with a shared-nothing architecture.

6. The method of claim 1 , wherein the query comprises a WHERE clause.

7. The method of claim 6 , wherein the index comprises a data structure created using one or more columns of the database table based on the WHERE clause.

8. The method of claim 1 , wherein the reduce function is not performed when the value of the output of the map function is unique.

9. A non-transitory computer-readable storage medium comprising program instructions for MapReduce implementations on indexed datasets in a distributed database environment, wherein execution of the program instructions by one or more processors of a computer system causes the one or more processors to carry out the steps of:

receiving a query in a query language from a client with a distributed database system;

locating an index that matches the query, wherein the index is pre-generated from a database table in the distributed database system, and wherein the index is maintained substantially current with a relevant modification of the database table;

executing a map function of a MapReduce programming model using the index; and

executing a reduce function of the MapReduce programming model using the output of the map function.

10. The non-transitory computer-readable storage medium of claim 9 , wherein the distributed database system comprises a scalable NoSQL database.

11. The non-transitory computer-readable storage medium of claim 9 , comprising further program instructions for the step of:

executing a finalize function on an output of the reduce function.

12. The non-transitory computer-readable storage medium of claim 11 , wherein the finalize function comprises

receiving a key and a value of the reduce function output and returns a finalized value in a list format.

13. A distributed database system comprising:

a processor;

a client node that provides a query in a query language to the distributed database system;

a distributed database system comprising a cluster of server nodes: and

a server node that:

creates at least one index from a data store in the distributed database,

maintains the at least one index in a substantially current state based on the data store,

receives a query from a client node,

matches the query to the at least one index when the query is received from the client node, and

implements a map function of a MapReduce programming model using the index.

14. The distributed database system of claim 13 , wherein the server node provides a map function output to the client node.

15. The distributed database system of claim 14 , wherein the client node implements a reduce function of the MapReduce programming model using the output of the map function.

16. The distributed database system of claim 14 , wherein the client node implements a finalize function using the output of the reduce function.

17. The distributed database system of claim 13 , wherein the server node implements the reduce function of the MapReduce programming model using the output of the map function.

18. The distributed database system of claim 17 , wherein the server node implements the finalize function using the output of the reduce function.

19. The distributed database system of claim 13 , wherein the server node provide the output of the finalize function or the output of the reduce function to the client node.

20. The distributed database system of claim 13 , wherein the server node creates at least one index based on the query from the client node.