Hash-join in parallel computation environments

US8370316B2 · kind B2 · utility

Assignee

• SAP AG · DE

Inventors

• Christian Bensberg · Heidelberg, DE
• Christian Mathis · Walldorf, DE
• Frederik Transier · Heidelberg, DE
• Nico Bohnsack · Ingersleben, DE
• Kai Stammerjohann · Wiesloch, DE

Key dates

• Filing date: Dec 23, 2010
• Grant date: Feb 5, 2013
• Expiry date: Jan 6, 2031

Classification

• Technology area (CPC G): Physics
• CPC primary: G06F16/24532
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

According to some embodiments, a system and method for a parallel join of relational data tables may be provided by calculating, by a plurality of concurrently executing execution threads, hash values for join columns of a first input table and a second input table; storing the calculated hash values in a set of disjoint thread-local hash maps for each of the first input table and the second input table; merging the set of thread-local hash maps of the first input table, by a second plurality of execution threads operating concurrently, to produce a set of merged hash maps; comparing each entry of the merged hash maps to each entry of the set of thread-local hash maps for the second input table to determine whether there is a match, according to a join type; and generating an output table including matches as determined by the comparing.