Cardinality estimation of a join predicate
AssigneeInternational Business Machines Corporation
InventorsSahana H. Anantharajaiah, Harjindersingh G. Mistry, Ajay M. Patil
Life of this patent
Estimating the term…
Abstract
In one embodiment, a method for improving cardinality estimation of a join predicate between a fact table and an overloaded dimension table is provided. The method includes receiving a dimension table and a fact table in a join predicate of one or more SQL statements. The method further includes identifying a majority of records in the fact table that refer to a subset of records in the dimension table. The method further includes computing a filter factor of the join predicate between the dimension table and the fact table. The method further includes creating a statistical view using one or more relevant portions of the dimension table that are referred to by the fact table.
Claims20
A computer-implemented method comprising:
- receiving, by one or more processors, a dimension table and a fact table in a join predicate of one or more SQL statements;
- identifying, by one or more computer processors, a majority of records in the fact table that refer to a subset of records in the dimension table;
- computing, by one or more computer processors, a filter factor of the join predicate between the dimension table and the fact table;
- and
- creating, by one or more processors, a statistical view using one or more relevant portions of the dimension table that are referred to by the fact table.
A computer program product comprising:
- one or more computer readable storage media and program instructions stored on the one or more computer readable storage media, the program instructions comprising:
- program instructions to receive a dimension table and a fact table in a join predicate of one or more SQL statements;
- program instructions to identify a majority of records in the fact table that refer to a subset of records in the dimension table;
- program instructions to compute a filter factor of the join predicate between the dimension table and the fact table;
- and
- program instructions to create a statistical view using one or more relevant portions of the dimension table that are referred to by the fact table.
A computer system comprising:
- one or more computer processors;
- one or more computer readable storage media;
- program instructions stored on the computer readable storage media for execution by at least one of the one or more processors, the program instructions comprising:
- program instructions to receive a dimension table and a fact table in a join predicate of one or more SQL statements;
- program instructions to identify a majority of records in the fact table that refer to a subset of records in the dimension table;
- program instructions to compute a filter factor of the join predicate between the dimension table and the fact table;
- and
- program instructions to create a statistical view using one or more relevant portions of the dimension table that are referred to by the fact table.
Dependencies are inferred from the claim text.