Efficient sequence number generation in a multi-system data-sharing environment

• US 6,952,707 B1
• Filed: 10/23/2000
• Issued: 10/04/2005
• Est. Priority Date: 06/11/1999
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Josten, Jeffrey William
• Primary Examiner(s): Amsbury, Wayne
• Assistant Examiner(s): NGUYEN, CAM LINH T
• Application Number:
  US09/694,185
• Time in Patent Office: 1,807 Days
• Field of Search: 707/104.1, 707/100, 707/8, 707/10, 707/202, 707/207
• US Class Current: 707/704
• CPC Class Codes: G06F 16/2308 Concurrency control transaction processing G06F9/466
• CPC Class Codes: G06F 16/2343 Locking methods, e.g. distributed locking or locking implementation details
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database
• CPC Class Codes: Y10S 707/99945 Object-oriented database structure processing
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

A method, apparatus, article of manufacture, and data structure for use in efficiently generating sequence numbers in a multi-system data-sharing environment. Sequence number assignment logic, performed by a computer system, generates a recoverable, unique sequence number for assignment to an application, wherein the sequence number is contained in a control page stored in a database on a data storage device coupled to the computer system and shared with other computer systems, and updates to the control page are serialized across all of the computer systems.

Claims

1. A computer-implemented system for assigning sequence numbers, comprising:

(a) a computer system; and

(b) sequence number assignment logic, performed by the computer system, for generating a recoverable, unique sequence number for assignment to an application, wherein the sequence number is contained in a control page stored in a database on a data storage device coupled to the computer system and shared with other computer systems, and updates to the control page are serialized across all of the computer systems.

2. The system of claim 1, wherein the control page includes one or more attributes selected from a group of attributes comprising an identifier, the sequence number (SN), a range value (N), and a starting sequence number (Starting SN).

3. The system of claim 2, wherein the identifier is a user-defined value that identifies a user for the sequence number.

4. The system of claim 2, wherein a value stored in N identifies a range of sequence number assignments.

5. The system of claim 1, wherein one or more attributes from the control page are stored in a data structure that is stored in the computer system.

6. The system of claim 5, wherein the data structure includes one or more attributes selected from a group of attributes comprising a sequence number (SN_MEM) and a “

number remaining”

value (N_REM).

7. The system of claim 6, wherein a value stored in N_REM indicates when a range of sequence numbers should be obtained from the control page.

8. The system of claim 1, wherein the control page is periodically saved to the data storage device, in order to effect a hardening of the control page.

9. The system of claim 1, wherein the sequence number assignment logic further comprises logic for latching the sequence number to serialize generation of the sequence number within the computer system.

10. The system of claim 1, wherein the sequence number assignment logic further comprises logic for physically locking the control page to serialize updates to the control page across multiple computer systems.

11. The system of claim 10, wherein the physical lock is not maintained when the computer system fails, so that other computer systems are not prevented from continuing to generate new sequence numbers.

12. A method of assigning sequence numbers in a computer-implemented system, comprising:

(a) generating a recoverable, unique sequence number using sequence number assignment logic performed by a computer system for assignment to an application; and

(b) storing the sequence number in a control page, wherein the control page is stored in a database on a data storage device coupled to the computer system and shared with other computer systems, and updates to the control page are serialized across all of the computer systems.

13. The method of claim 12, wherein the control page includes one or more attributes selected from a group of attributes comprising an identifier, the sequence number (SN), a range value (N), and a starting sequence number (Starting SN).

14. The method of claim 13, wherein the identifier is a user-defined value that identifies a use for the sequence number.

15. The method of claim 13, wherein a value stored in N identifies a range of sequence number assignments.

16. The method of claim 12, wherein one or more attributes from the control page are stored in a data structure that is stored in the computer system.

17. The method of claim 16, wherein the data structure includes one or more attributes selected from a group of attributes comprising a sequence number (SN_MEM) and a “

number remaining”

value (N_REM).

18. The method of claim 17, wherein a value stored in N_REM indicates when a range of sequence numbers should be obtained from the control page.

19. The method of claim 12, wherein the control page is periodically saved to the data storage device, in order to effect a hardening of the control page.

20. The method of claim 12, wherein the sequence number assignment step further comprises latching the sequence number to serialize generation of the sequence number within the computer system.

21. The method of claim 12, wherein the sequence number assignment step further comprises physically locking the control page to serialize updates to the control page across multiple computer systems.

22. The method of claim 21, wherein the physical lock is not maintained when the computer system fails, so that other computer systems are not prevented from continuing to generate new sequence numbers.

23. An article of manufacture embodying logic for performing a method of assigning sequence numbers in a computer-implemented system, the method comprising:

(a) generating a recoverable, unique sequence number using sequence number assignment logic performed by a computer system for assignment to an application; and

(b) storing the sequence number in a control page, wherein the control page is stored in a database on a data storage device coupled to the computer system and shared with other computer systems, and updates to the control page are serialized across all of the computer systems.

24. The of manufacture of claim 23, wherein the control page includes one or more attributes selected from a group of attributes comprising an identifier, the sequence number (SN), a range value (N), and a starting sequence (Starting SN).

25. The article of manufacture of claim 24, wherein the identifier is a user-defined value that identifies a use for the sequence number.

26. The article of manufacture of claim 24, wherein a value stored in N identifies a range of sequence number assignments.

27. The article of manufacture of claim 23, wherein one or more attributes from the control page are stored in a data structure that is stored in the computer system.

28. The article of manufacture of claim 27, wherein the data structure includes one or more attributes selected from a group of attributes comprising a sequence number (SN_MEM) and a “

number remaining”

value (N_REM).

29. The article of manufacture of claim 28, wherein a value stored in N_REM indicates when a range of sequence numbers should be obtained from the control page.

30. The article of manufacture of claim 23, wherein the control page is periodically saved to the data storage device, in order to effect a hardening of the control page.

31. The article of manufacture of claim 23, wherein the sequence number assignment step further comprises latching the sequence number to serialize generation of the sequence number within the computer system.

32. The article of manufacture of claim 23, wherein the sequence number assignment step further comprises physically locking the control page to serialize updated to the control page across multiple computer systems.

33. The article of manufacture of claim 32, wherein the physical lock is not maintained when the computer system fails, so that other computer systems are not prevented from continuing to generate new sequence numbers.

34. A data structure by a sequence number assignment logic performed by a computer system, the data structure comprising:

a control page that contains a sequence number that has no restrictions on its size, an identifier that is a user-defined value that identifies a use for the sequence number, a range value (N) that identifies a range of sequence number assignments, and a starting sequence number (Starting SN) that comprises an initial value for the sequence number, wherein the control page is stored in a database on a data storage device coupled to the computer system and shared with other computer systems, and update to the control page are serialized across all of the computer systems.

35. The data structure of claim 34, wherein one or more attributes from the control page are stored in an in-memory data structure in the computer system.

36. The data structure of claim 35, wherein the in-memory data structure includes one or more attributes selected from a group of attributes comprising a sequence number (SN_MEM) and a “

number remaining”

value (N_REM).

37. The data structure of claim 36, wherein a value stored in N_REM indicates when a range of sequence numbers should be obtained from the control page.

38. The data structure of claim 35, wherein the control page is periodically saved to a data storage device, in order to effect a hardening of the control page.

39. The data structure of claim 35, wherein the sequence number is latched to serialized generation of the sequence number within the computer system.

40. The data structure of claim 35, wherein the control page is physically locked by a computer system to serialize updates to the control page across multiple computer systems.

41. The data structure of claim 40, wherein the physical lock is not maintained when the computer system fails, so that other computer systems are not prevented from continuing to generate new sequence numbers.