Access path for database optimizer
AssigneeInternational Business Machines Corporation
InventorsShuo Li, Xiaobo Wang, Sheng Yan Sun, Hong Mei Zhang
Life of this patent
Estimating the term…
Abstract
In a computer-implemented method for improving performance of a database optimizer, a processor calculates a first execution time for a database query executing through a first access path of a database system. A processor generates a second access path. A processor determines a second execution time via a simulation of the database query through the second access path. A processor determines that the second execution time is less than the first execution time. A processor, responsive to determining that the second execution time is less than the first execution time, sends the second access path to the database optimizer.
Claims20
A computer-implemented method for improving performance of a database optimizer, comprising:
- calculating a first execution time for a database query executing through a first access path of a database system;
- generating a second access path;
- determining a second execution time for the database query executing through the second access path;
- determining that the second execution time is less than the first execution time;
- and
- responsive to determining that the second execution time is less than the first execution time, sending the second access path to the database optimizer.
The method of claim 6, wherein the system performance factors comprise a selection from the group consisting of:
- a real-time table cardinality, a real-time column cardinality, a filter factor, a buffer pool hit ratio, and a prefetch efficiency.
A computer program product comprising:
- one or more computer readable storage media, and program instructions collectively stored on the one or more computer readable storage media, the program instructions comprising:
- program instructions to calculate a first execution time for a database query executing through a first access path of a database system;
- program instructions to generate a second access path;
- program instructions to determine a second execution time for the database query executing through the second access path;
- program instructions to determine that the second execution time is less than the first execution time;
- and
- program instructions to, responsive to determining that the second execution time is less than the first execution time, send the second access path to the database optimizer.
A computer system comprising:
- one or more computer processors, one or more computer readable storage media, and program instructions collectively stored on the one or more computer readable storage media for execution by at least one of the one or more computer processors, the program instructions comprising:
- program instructions to evaluate, by one or more processors, a specimen chart relative to a chart erratum model comprising features mapped to an optimum state for a first chart type;
- program instructions to generate a first risk score for a first sample feature of the specimen chart, wherein the first risk score comprises a delta from the optimum state;
- and
- program instructions to refactor the specimen chart to mitigate the first risk score of the first sample feature.
Dependencies are inferred from the claim text.