公开(公告)号：US20170147644A1

公开(公告)日：2017-05-25

申请号：US14947252

申请日：2015-11-20

Applicant: SAP SE

Inventor： Taehyung LEE ,  Joo Young Yoon ,  Sang Il Song ,  Yongsik Yoon ,  Sung Heun Wi ,  Junhee Woo

IPC: G06F17/30

CPC classification number: G06F17/30466 ,  G06F17/30

Abstract: Disclosed herein are system, method, and computer program product embodiments for utilizing join cardinality to improve the performance of query processing. An embodiment operates by a database engine receiving a query including a join operation on a first and a second table using a join predicate, and a tag for the join operation indicating a cardinality relationship between the first and the second table when satisfying the join predicate. Then, the database engine generates a query processing plan for performing the query. For the join operation, the database engine selects one of the first or the second tables to remove from the join operation based on a type of the join operation and the tag. Based on the selecting, the database engine may remove may the join operation and the selected table from the query processing plan.