SORTING AND MERGING OF FILES IN A MULTIPROCESSOR

In a multiprocessor system (FIG. 1), file sorting and merging operations are broken down into a series of partial-file sorts and partial-file merges which are executed in parallel by a plurality of processors (21-26). In a file sorting operation, an input file processor (24) distributes segments (201) of an input file (200) from disk (34) to a plurality of sort processors (21-23) in a round-robin fashion. Each sort processor sorts records (203) of each received segment according to a key, and stores the sorted segments on disk (35) in a temporary file (220). A merge operation is then performed on the sorted segments, treating each segment as an input file. In a merge operation, a plurality of merge processors (21-23) each retrieve a different plurality of sorted segments block (202)-by-block from the temporary file, merge the records of the retrieved segments, and supply records of the merged segments to an output file processor (26). The output file processor merges the records received from the plurality of merge processors and stores them in an output file (230) on disk (36).