Program for capturing data changes utilizing data-space tracking

• US 8,200,664 B2
• Filed: 10/29/2008
• Issued: 06/12/2012
• Est. Priority Date: 07/19/2002
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Beier, Harley A., Watts, Vern L.
• Primary Examiner(s): To, Baoquoc
• Application Number:
  US12/260,565
• Publication Number:
  US 20090063553A1
• Time in Patent Office: 1,322 Days
• Field of Search: None
• US Class Current: 707/726
• 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

A program for reorganizing information in a computer system while concurrently providing access to the information for updates. In an exemplary embodiment of the invention, 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 computer program embodied on a computer readable medium for reorganizing information in a computer system having an original data-space that contains a plurality of sequentially stored original data-elements, a shadow data-space that contains a plurality of shadow data-elements, a data data-space that contains a plurality of data data-elements, and an index data-space that contains a plurality of sequentially stored index data-elements, the computer program 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;

program instructions for recording a location of the original data-element and a location of the shadow data-element within a data data-element within the data data-space, thereby associating the original data-element, the shadow data-element and the data data-element;

program instructions for recording a location of the data data-element within an index data-element within the index data-space, wherein the index data-elements in the index data-space are arranged in the same sequence as their associated original data-elements in the original data-space;

program instructions for recording in the data data-element information indicating that a change has occurred in the original data-element associated with the data data-element; and

program instructions for applying the change in the original data-element to the shadow data-element associated with the original data-element, in response to detecting the change associated with the original data-element recorded in the data data-element,

wherein the location of the shadow data-element recorded in the data data-element includes an offset of the shadow data-element from a base address of the shadow data-space.

2. The computer program of claim 1, wherein said program instructions for recording in the data data-element information indicating that a change has occurred in the original data-element, further comprise:

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

program instructions for determining a location of the changed original data-element; and

program instructions for updating the data data-element associated with the changed original data-element to record the information indicating that a change occurred and to record a type of change that occurred.

3. The computer program of claim 2, wherein if the log request indicates that the change is an addition of a new original data-element to the original data-space, the computer program further comprises:

program instructions for adding the data data-element to the data data-space and storing a location of the original data-element within the data data-element; and

program instructions for recording a location of the data data-element within the index data-element in the index data-space, wherein the index data-elements in the index data-space are arranged in the same sequence as their associated original data-elements in the original data-space.

4. The computer program of claim 2, wherein the data data-element is updated to record information indicating that the original data-element has been at least one of added, updated and deleted.

5. The computer program of claim 1, wherein said program instructions for applying the change in the original data-element to its associated shadow data-element, comprises at least one of:

program instructions for adding the shadow data-element to said shadow data-space and storing a location of the shadow data-element within the data data-element, if the data data-element indicates that the original data-element was added to the original data-space;

program instructions for copying the contents of the original data-element to the shadow data-element by locating the original data-element and shadow data-element from the location information recorded in the data data-element, if the data data-element indicates that the original data-element was one of updated and added; and

program instructions for deleting the shadow data-element by locating the shadow data-element from the location information recorded in the data data-element, if the data data-element indicates that the original data-element located at the original data-element location stored within the data data-element was deleted.

6. The computer program of claim 1, wherein the index data-space and data data-space are stored in non-persistent storage.

7. The computer program of claim 1, wherein the index data-space and data data-space are stored in persistent storage.

8. The computer program of claim 1, wherein the location of the shadow data-element recorded in the data data-element includes a sequential position of the shadow data-element within the shadow data-space.

9. The computer program of claim 1, wherein the location of the data data-element recorded in the index data-element is determined by multiplying a sequential position of the data data-element within the data data-space by a bit length of the plurality of data data-elements within the data data-space.

10. The computer program of claim 1, wherein the location of the data data-element within the data data-space is determined by dividing a relative base address of the data data-element by a bit length of the plurality of data data-elements within the data data-space.

11. The computer program of claim 1, wherein the original data-space contains a plurality of original data-elements of a first bit length and the index data-space contains a plurality of index data-elements of a second bit length.

12. The computer program of claim 11, wherein the first bit length and the second bit length are the same length.

13. The computer program of claim 11, wherein a location of the index data-element is determined from the location of its associated original data-element by dividing the location of the original data-element by the first bit length to produce a result and multiplying the result by the second bit length.

14. The computer program of claim 11, wherein the location of the original data-element is determined from a location of the index data-element by dividing a relative base address of the index data-element by the second bit length to produce a result and multiplying the result by the first bit length.