Recovering different types of objects with one pass of the log

• US 6,119,128 A
• Filed: 03/30/1998
• Issued: 09/12/2000
• Est. Priority Date: 03/30/1998
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Hu, Ming-Hung, Courter, Daniel Keith, Ruddy, James Alan, Kunioka-Weis, Laura Michiko, Wang, Yufen, Majithia, Thomas, Matamoros, Deborah A.
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): Mizrahi, Diane D.
• Application Number:
  US09/050,554
• Time in Patent Office: 897 Days
• Field of Search: 707/200, 707/201, 707/202, 707/203, 707/204, 707/205
• US Class Current: 1/1
• CPC Class Codes: G06F 16/2358 Change logging, detection, and notification replication G06F16/27
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

A method, apparatus, and article of manufacture for a computer implemented recovery system for restoring a database in a computer. The database contains objects and is stored on a primary data storage device connected to the computer. Objects of different types in the database are copied from the primary data storage device to a secondary data storage device. Modifications to the objects are logged in a log file. A recovery indicator is received that indicates that recovery of the objects in the database is required. The objects are copied from the secondary data storage device to the database on the primary data storage device. Modifications in the log file are applied to the copied objects during one pass through the log file.

Claims

1. A method of restoring a database in a computer, the database containing objects and being stored on a primary data storage device connected to the computer, the method comprising the steps of:

copying objects of different types in the database from the primary data storage device to a secondary data storage device, wherein one of the objects is a table index for locating data in a table, and wherein one of the objects is a partitioning index for defining a scope of each partition and thereby assigning a row of the table to its respective partition;

logging modifications to the objects, including the table index and the partitioning index, in a log file;

receiving a recovery indicator indicating that recovery of the objects in the database is required;

copying the objects, including the table index and the partitioning index, from the secondary data storage device to the database on the primary data storage device; and

applying the modifications in the log file to the copied objects, including the table index and the partitioning index, during one pass through the log file.

2. The method of claim 1, wherein the types of the objects include table data.

3. The method of claim 1, wherein the types of the objects include partition indexes.

4. The method of claim 1, wherein the recovery indicator indicates that modifications to the objects are to be reversed.

5. The method of claim 1, wherein the recovery indicator indicates that the objects have been corrupted.

6. The method of claim 1, further comprising the step of maintaining log ranges.

7. The method of claim 1, further comprising the step of maintaining copy information for objects that are copied.

8. The method of claim 7, further comprising the step of determining a starting point in the log file based on the copy information.

9. An apparatus for restoring a database in a computer, comprising:

a computer having a primary data storage device connected thereto, wherein the primary data storage device stores a database containing objects;

one or more computer programs, performed by the computer, for copying objects of different types in the database from the primary data storage device to a secondary data storage device, wherein one of the objects is a table index for locating data in a table, and wherein one of the objects is a partitioning index for defining a scope of each partition and thereby assigning a row of the table to its respective partition, logging modifications to the objects, including the table index and the partitioning index, in a log file, receiving a recovery indicator indicating that recovery of the objects in the database is required, copying the objects, including the table index and the partitioning index, from the secondary data storage device to the database on the primary data storage device, and applying the modifications in the log file to the copied objects, including the table index and the partitioning index, during one pass through the log file.

10. The apparatus of claim 9, wherein the types of the objects include table data.

11. The apparatus of claim 9, wherein the types of the objects include partition indexes.

12. The apparatus of claim 9, wherein the recovery indicator indicates that modifications to the objects are to be reversed.

13. The apparatus of claim 9, wherein the recovery indicator indicates that the objects have been corrupted.

14. The apparatus of claim 9, further comprising the means for maintaining log ranges.

15. The apparatus of claim 9, further comprising the means for maintaining copy information for objects that are copied.

16. The apparatus of claim 15, further comprising the means for determining a starting point in the log file based on the copy information.

17. An article of manufacture comprising a computer program carrier readable by a computer and embodying one or more instructions executable by the computer to perform method steps for restoring a database, the database containing objects and being stored on a primary data storage device connected to the computer, the method comprising the steps of:

copying objects of different types in the database from the primary data storage device to a secondary data storage device, wherein one of the objects is a table index for locating data in a table, and wherein one of the objects is a partitioning index for defining a scope of each partition and thereby assigning a row of the table to its respective partition;

logging modifications to the objects, including the table index and the partitioning index, in a log file;

receiving a recovery indicator indicating that recovery of the objects in the database is required;

copying the objects, including the table index and the partitioning index, from the secondary data storage device to the database on the primary data storage device; and

applying the modifications in the log file to the copied objects, including the table index and the partitioning index, during one pass through the log file.

18. The method of claim 17, wherein the types of the objects include table data.

19. The method of claim 17, wherein the types of the objects include partition indexes.

20. The method of claim 17, wherein the recovery indicator indicates that modifications to the objects are to be reversed.

21. The method of claim 17, wherein the recovery indicator indicates that the objects have been corrupted.

22. The method of claim 17, further comprising the step of maintaining log ranges.

23. The method of claim 17, further comprising the step of maintaining copy information for objects that are copied.

24. The method of claim 23, further comprising the step of determining a starting point in the log file based on the copy information.