Cache Configuration in a Database System

• US 20080071987A1
• Filed: 04/11/2007
• Published: 03/20/2008
• Est. Priority Date: 09/20/2006
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: KARN, Holger, MILLER, Sven
• Granted Patent: US 7,788,449 B2
• Time in Patent Office: Days
• US Class Current: 711/118
• CPC Class Codes: G06F 12/0802 Addressing of a memory level in which the access to the desired data or data block requires associative addressing means, e.g. caches
• CPC Class Codes: G06F 2212/601 Reconfiguration of cache memory

Abstract

A computer-implemented method is disclosed. The method includes collecting cache-efficiency-indicator values of an at least one cache fragment during operation of a database system over a period of time. Providing approximation-function-parameter values for the collected, cache-efficiency-indicator values, an approximation function representing a relation between a cache-efficiency-indicator and the size of a respective cache fragment. The method continues by providing a set of workload windows based on the approximation-function-parameter values. Next, providing a workload-window information for the set of workload windows, the workload-window information including at least one approximation-function-parameter value representing each determined workload window. The method further includes storing the workload-window information for a comparison based on current, cache-efficiency-indicator values and the workload-window information.

Claims

1. A computer-implemented method for providing workload windows in a database system having at least one cache fragment, the method comprising:

collecting cache-efficiency-indicator values of an at least one cache fragment during operation of a database system over a period of time;

providing approximation-function-parameter values for the collected, cache-efficiency-indicator values, an approximation function representing a relation between a cache-efficiency-indicator and size of a respective cache fragment;

providing a set of workload windows based on the approximation-function-parameter values;

providing workload-window information for the set of workload windows, the workload-window information including at least one approximation-function-parameter value representing each determined workload window; and

storing the workload-window information for a comparison based on current, cache-efficiency-indicator values and the workload-window information.

2. The computer-implemented method of claim 1 wherein providing the set of workload windows comprises finding time periods where the approximation-parameter values remain substantially constant.

3. The computer-implemented method of claim 1 further comprising discarding a potential workload window if the duration of the potential workload window is shorter than a predefined value.

4. The computer-implemented method of claim 1, wherein the workload-window information comprises at least one of the following:

start time of a workload window, stop time of a workload window, and statistical information about the approximation-parameter values within the workload window.

5. The computer-implemented method of claim 1 further comprising:

providing a set of current, cache-efficiency-indicator values for the at least one cache fragment;

modelling the current, cache-efficiency-indicator values for each cache segment with an approximation function;

selecting a workload window having workload-window information matching the at least one approximation function modelling the set of current, cache-efficiency-indicator values; and

adjusting cache configuration based on workload-window information of the selected workload window.

6. The computer-implemented method of claim 5, comprising updating the workload-window information based on the set of current, cache-efficiency-indicator values.

7. A database system comprising at least one cache fragment and a cache controller, the cache controller configured to:

collect cache-efficiency-indicator values of the at least one cache fragment over a period of time;

provide approximation-function-parameter values for the collected, cache-efficiency-indicator values, an approximation function representing a relation between a cache-efficiency-indicator and size of a respective cache fragment;

provide a set of workload windows based on the approximation-function-parameter values;

provide workload-window information for the set of workload windows based on the collected, cache-efficiency-indicator values, the workload-window information including at least one approximation-function-parameter value representing each determined workload window; and

store the workload-window information for a comparison based on current, cache-efficiency-indicator values and the workload-window information.

9. The database of claim 7, wherein providing the set of workload windows comprises finding time periods where the approximation-parameter values remain substantially constant.

10. The database of claim 7 further comprising discarding a potential workload window if the duration of the potential workload window is shorter than a predefined value.

11. The database of claim 7, wherein the workload-window information comprises at least one of the following:

start time of a workload window, stop time of a workload window, and statistical information about the approximation-parameter values within the workload window.

12. The database of claim 7 further comprising:

providing a set of current, cache-efficiency-indicator values for the at least one cache fragment;

modelling the current, cache-efficiency-indicator values for each cache segment with an approximation function;

selecting a workload window having workload-window information matching the at least one approximation function modelling the set of current, cache-efficiency-indicator values; and

adjusting cache configuration based on workload-window information of the selected workload window.

13. The database of claim 7 comprising updating the workload-window information based on the set of current, cache-efficiency-indicator values.

8. A computer program product comprising a computer-usable medium including a computer-readable storage medium, wherein the computer-readable storage medium when executed on a data processing system causes the data processing system to:

collect cache-efficiency-indicator values of at least one cache fragment over a period of time;

provide approximation-function-parameter values for the collected cache-efficiency-indicator values, an approximation function representing a relation between a cache-efficiency-indicator and size of a respective cache fragment;

provide a set of workload windows based on the approximation function parameter values;

provide workload-window information for the set of workload windows based on the collected cache-efficiency-indicator values, the workload-window information including at least one approximation-function-parameter value representing each determined workload window; and

store the workload-window information for a comparison based on current cache-efficiency-indicator values and the workload-window information.

14. The computer program product of claim 8, wherein providing the set of workload windows comprises finding time periods where the approximation-parameter values remain substantially constant.

15. The computer program product of claim 8 further comprising discarding a potential workload window if the duration of the potential workload window is shorter than a predefined value.

16. The computer program product of claim 8 wherein the workload-window information comprises at least one of the following:

start time of a workload window, stop time of a workload window, and statistical information about the approximation-parameter values within the workload window.

17. The computer program product of claim 8 further comprising:

providing a set of current, cache-efficiency-indicator values for the at least one cache fragment;

modelling the current, cache-efficiency-indicator values for each cache segment with an approximation function;

selecting a workload window having workload-window information matching the at least one approximation function modelling the set of current, cache-efficiency-indicator values; and

adjusting cache configuration based on workload-window information of the selected workload window.

18. The computer program product of claim 8,comprising updating the workload-window information based on the set of current, cache-efficiency-indicator values.