The present invention, in an example embodiment, provides a special-purpose formal language and translator for the parallel processing of large databases in a distributed system. The special-purpose language has features of both a declarative programming language and a procedural programming language and supports the co-grouping of tables, each with an arbitrary alignment function, and the specification of procedural operations to be performed on the resulting co-groups. The language's translator translates a program in the language into optimized structured calls to an application programming interface for implementations of functionality related to the parallel processing of tasks over a distributed system. In an example embodiment, the application programming interface includes interfaces for MapReduce functionality, whose implementations are supplemented by the embodiment.