Sorting of records with duplicate removal in a database system

摘要: A database system includes an enhanced technique for performing sorts in which removals of duplicate records are performed to compact the size segments being sorted. To enhance a query plan, record removal is as early plan possible. By removing number input/output (I/O) operations reduced, resulting more efficient usage resources. In example implementations, two type performed: heap sort (to successive input file, with sorting associated concurrent each segment so that smaller I/O accesses needed); and merge (in output files from prior passes merged sorted, process also further data reduce accesses).