1. A business rules application parallel processing system, comprising: at least one computer system; a data source with stored data; and an application that, when executed on the at least one computer system, performs a two-part parallel processing procedure external to the data source, wherein a first part of the two-part parallel processing procedure comprises, performing a query to extract data from the data source for processing in accordance with at least one business rule applied by at least one business rules application; storing data extracted from the data source in a sequential file format as a first data set; partitioning the data in the first data set in accordance with the at least one business rule to create a second data set and to prepare the data in the second data set for processing; wherein a second part of the two-part parallel processing procedure comprises, queuing the at least one business rules application in the at least one computer system; accessing the partitioned data from the second data set; partitioning the accessed data into partition units appropriate for scaled application processing across multiple processors in the at least one computer system to create a third data set; processing the data in the third data set in a parallel execution across the multiple processors wherein processor usage is balanced and processing comprises at least one of join and summarization operations to produce a processing output; and combining the processing output after said processing in accordance with the at least one business rule of the at least one business rules application as a fourth data set, and wherein the application is configured to perform the first part of the two-part parallel processing procedure less often than the second part of the two-part parallel processing procedure to efficiently apply different business rules during the second part to data queried from the data source during the first part.