International Business Machines Corporation
DYNAMICALLY SELECTING A DATA ACCESS PATH TO IMPROVE QUERY PERFORMANCE

Abstract:

An approach is provided for accessing data in a database. A query which accesses item(s) in the data is received. The query has multiple conditions whose execution produces a final result. Amounts of filtering of portions of the data caused by utilizing different types of indexes to filter the portions are determined. Greatest amounts of filtering for the portions are determined. Types of indexes are selected so that a utilization of a given type of index causes a greatest amount of filtering for a given portion. Data access methods for the portions of data are generated. During runtime, process tasks are generated for the multiple conditions in the query. An execution flow is controlled. The execution flow executes the process tasks by utilizing the data access methods to generate initial results. The final result of the query is generated by combining the initial results from the process tasks.