Patent ID: 8600994
Filing Date: 2013-12-03
Classification: G06F

Abstract:
1. A computer-based method for outer joining a small table S to a large table L on a join condition, the method being implemented on a computer database system with a plurality B of parallel units (PUs), S and L being partitioned across the PUs, each row in S having a unique row-id, executed by at least one processor, the method comprising: a) the computer database system duplicating each row of S on all PUs to form S b) on each PU, the computer database system identifying dangling rows in S, wherein the dangling rows in S are those rows in S that do not have a match in L under the join condition and saving the row-ids of the dangling rows in T c) the computer database system forming P from dangling rows of S whose corresponding entries in T d) the computer database system producing a result by unioning P and I, I being formed by inner joining non-dangling rows of S with L; and e) the computer database system saving the result.