International Business Machines Corporation

Adarsh R Pannu

You-Chin Gene Fuh

Patrick Dooling Bossman

Curt Lee Cotner

Terence Patrick Purcell

Thomas Abel Beavin

Snehal S Antani

John Joseph Campbell

Chon N Lei

Frank Darl Bower

Rajesh P Ramachandran

Kun Peng Ren

Terrence P Purcell

An adaptive query execution plan enhancement is provided by: selecting a sample of literal sets from an execution history of a query statement; determining a plurality of access paths by applying each literal set in the sample to the query statement; for each given access path of the plurality of access paths, determining a total execution cost by applying each literal set in the sample to the given access path; and selecting a preferred access path from the plurality of access paths based on the total execution costs for each given access path. A plurality of preferred access paths for a plurality of query statements in an application workload is collected and may be presented as a query execution plan enhancement recommendation to users.

Adaptive query execution plan enhancement

An apparatus, system, and method are disclosed for improving query execution plan efficiency in a database management system. The present invention binds both static database queries and dynamic database queries to new query execution plans (QEPs) that produce the same result set as a former QEP bound to the database queries. Next, the present invention identifies one of the former QEPs and the new QEP as an active QEP and automatically collects execution statistics for one of the former QEPs and the new QEP. Finally, the present invention automatically selects one of the former QEPs and the new QEP as the active QEP in response to completion of the automatic collection of execution statistics, the active QEP selected such that the automatically selected QEP provides optimal execution performance based on performance criteria in comparison to the automatically unselected QEP, the active QEP selected based on the execution statistics.

Query execution plan efficiency in a database management system

A computer program product for database query optimization including a computer usable medium having a computer readable program, wherein the computer readable program, when executed on a computer, causes the computer to receive a database query, search the database query for a literal term, replace the literal term in the database query with a placeholder term to put the database query in a template form, search a directory for a replacement query that corresponds to the database query in the template form, replace the database query with the replacement query and include the placeholder term in the replacement query, and replace the placeholder term in the replacement query with the corresponding literal term to put the replacement query in an executable format, wherein the replacement query is an optimized substitute for the database query.

Computer program product for database query optimization

An apparatus, system, and method are disclosed for ensuring query execution plan stability in a database management system. The present invention binds a static database query to a new query execution plan (QEP) that produces the same result set as an original QEP bound to the static database query. Next, the present invention identifies one of the original QEP and the new QEP as a primary QEP and automatically collects execution statistics for the original QEP and the new QEP. Finally, the present invention automatically selects one of the original QEP and the new QEP as the primary QEP in response to completion of the automatic collection of execution statistics, the primary QEP selected such that the automatically selected QEP provides optimal execution performance based on performance criteria in comparison to the automatically unselected QEP, the primary QEP selected based on the execution statistics.

Apparatus, system, and method for ensuring query execution plan stability in a database management system

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San Jose, CA, United States of America

Adarsh R Pannu