Capturing data changes utilizing data-space tracking

• US 7,085,787 B2
• Filed: 07/19/2002
• Issued: 08/01/2006
• Est. Priority Date: 07/19/2002
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Watts, Vern L., Beier, Harley A.
• Primary Examiner(s): Corrielus, Jean M.
• Assistant Examiner(s): To, Baoquoc N.
• Application Number:
  US10/197,810
• Publication Number:
  US 20040015468A1
• Time in Patent Office: 1,474 Days
• Field of Search: 707/202, 707/203, 707/204, 707/200
• US Class Current: 1/1
• CPC Class Codes: G06F 16/2282 Tablespace storage structures; Management thereof
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99955 Archiving or backup

Abstract

An on-line reorganization facility (ORF) uses index data-spaces that point to other data-spaces, referred to as data data-spaces, to efficiently track and coordinate information about the data-elements in an original data-space operated upon by a reorganization process. A relative base address of a data-element in an index data-space can be derived from a relative base address of a data-element in an original data-space, and vice versa. An index data-space data-element contains a location of a data-element in a data data-space that tracks change information related to a corresponding data-element in the original data-space. Tracked changes are later applied to the newly reorganized data-space to assure consistency and integrity of the data. Tracked changes include the location in the original data-space where the change occurred and a flag indicting the type of change.

Claims

1. A method of reorganizing a database and concurrently providing access to the database for updates, the database including an original data-space having a plurality of original data-elements and a shadow data-space having a plurality of shadow data-elements, the method comprising:

copying contents of an original data-element within the original data-space to a shadow data-element within the shadow data-space;

reorganizing the shadow data-space;

keeping track of a location of an original data-element that is changed after the contents of the original data-element are copied to the shadow data-element; and

copying data from the location of the changed original data-element to a location of a shadow data-element in the reorganized shadow data-space corresponding to the changed original data-element,

wherein said keeping track of a location of an original data-element that is changed, comprises;

intercepting a log request that indicates a change to the original data-element;

recording in a data data-element in a data data-space information indicating that the original data-element changed; and

recording a location of the data data-element in an index data-element of an index data-space, wherein a location of the index data-element within the index data-space corresponds to the location of the original data-element within the original data-space.

2. The method of claim 1, wherein the information recorded in the data data-element in the data data-space includes a type of change that occurred.

3. The method of claim 2, wherein the type of change recorded is at least one of an addition, an update, and a deletion.

4. The method of claim 1, wherein the information indicating that the original data-element changed is recorded in non-persistent storage.

5. The method of claim 1, wherein the information indicating that the original data-element changed is recorded in persistent storage.

6. The method of claim 1, wherein said recording information indicating that the original data-element changed includes recording a position of the original data-element within the original data-space.

7. The method of claim 6, wherein the recorded position of the original data-element includes an offset of the original data-element from a base-address of the original data-space.

8. A computer program embodied on a computer readable medium for reorganizing a database and concurrently providing access to the database for updates, the database including an original data-space having a plurality of original data-elements, a shadow data-space having a plurality of shadow data-elements, a data data-space having a plurality of data data-elements and an index data-space having a plurality of index data-elements, the method comprising:

program instructions for copying contents of an original data-element within the original data-space to a shadow data-element within the shadow data-space and associating the original data-element and shadow data-element using a data data-element;

program instructions for reorganizing the shadow data-space;

program instructions for keeping track of a location of an original data-element that is changed after the contents of the original data-element are copied to the shadow data-element by using the data data-element that is located using an index data-element; and

program instructions for copying data from the location of the changed original data-element to a location of a shadow data-element in the reorganized shadow data-space corresponding to the changed original data-element, wherein said program instructions for keeping track of a location of an original data-element that is changed, comprises;

program instructions for intercepting a log request that indicates a change to the original data-element;

program instructions for recording information in the data data-element in the data data-space indicating that the original data-element changed; and

program instructions for recording a location of the data data-element in the index data-element of the index data-space, wherein a location of the index data-element within the index data-space corresponds to the location of the original data-element within the original data-space.

9. The computer program of claim 8, wherein the information recorded in the data data-element in the data data-space includes a type of change that occurred.

10. The computer program of claim 9, wherein the type of change recorded is at least one of an addition, an update, and a deletion.

11. The computer program of claim 8, wherein the information indicating that the original data-element changed is recorded in non-persistent storage.

12. The computer program of claim 8, wherein the information indicating that the original data-element changed is recorded in persistent storage.

13. The computer program of claim 8, wherein said program instructions for recording information indicating that the original data-element changed includes recording a position of the original data-element within the original data-space.

14. The computer program of claim 13, wherein the recorded position of the original data-element includes an offset of the original data-element from a base-address of the original data-space.