Method and apparatus for filtering lock requests

• US 6,772,255 B2
• Filed: 12/14/2000
• Issued: 08/03/2004
• Est. Priority Date: 06/30/1998
• Status: Expired due to Term

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Daynes, Laurent
• Primary Examiner(s): Ray, Gopal C.
• Application Number:
  US09/738,895
• Publication Number:
  US 20010032281A1
• Time in Patent Office: 1,328 Days
• Field of Search: 710/200, 710/240, 710/108, 710/107, 710/36, 707/1, 709/104, 709/107, 709/201, 709/100, 711/147, 711/152, 711/113, 714/30, 712/208, 717/136, 717/148
• US Class Current: 710/200
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database

Abstract

Method and apparatus for locking by sharing lock states. Each resource is associated with a lock state that represents its lock. Lock states are made of one set of transactions per locking mode. Resources may share the same lock state if the state of their respective locks is equal. Locking operations change the association between a resource and a lock state to reflect changes to the resource'"'"'s lock.

Claims

1. A method for managing access to a plurality of resources comprising:

obtaining a request from a transaction to lock a resource; and

obtaining an association of said transaction and a lock state related to said resource;

wherein said obtaining said association of said transaction and said lock state further comprises obtaining a pointer from said transaction to said lock state.

2. The method of claim 1 wherein said obtaining said association of said transaction and said lock state further comprises obtaining said lock state from a data cache if a first test result indicates a failure.

3. A method for managing access to a plurality of resources comprising:

obtaining a request from a transaction to lock a resource; and

obtaining an association of said transaction and a lock state related to said resource;

wherein said obtaining said association of said transaction and said lock state further comprises computing a bitmap value utilizing said transaction and said lock state.

4. The method of claim 3 wherein said obtaining said association of said transaction and said lock state further comprises:

comparing said lock state retrieved from said data cache with said bitmap value; and

producing a second test result.

5. A method for managing access to a plurality of resources comprising:

obtaining a request from a transaction to lock a resource; and

obtaining an association of said transaction and a lock state related to said resource;

wherein said obtaining said association of said transaction and said lock state further comprises comparing said lock state and a bitmap value and producing a first test result.

6. The method of claim 5 wherein said obtaining said association and said lock state further comprises calling a lock manager if at least one of said first test result and a second test result indicates a failure.

7. A system comprising:

a processor;

a memory coupled to said processor;

object code executed by said processor for managing access to a plurality of resources, said object code comprising;

a method obtaining a request from a transaction to lock a resource; and

a method obtaining an association of said transaction and a lock state related to said resource;

wherein said method obtaining said association of said transaction and said lock state further comprises a method obtaining a pointer from said transaction to said lock state.

8. The system of claim 7 wherein said method obtaining said association of said transaction and said lock state further comprises a method obtaining said lock state from a data cache if a first test result indicates a failure.

9. A system comprising:

a processor;

a memory coupled to said processor;

object code executed by said processor for managing access to a plurality of resources, said object code comprising;

a method obtaining a request from a transaction to lock a resource; and

a method obtaining an association of said transaction and a lock state related to said resource;

wherein said method obtaining said association of said transaction and said lock state further comprises a method computing a bitmap value utilizing said transaction and said lock state.

10. The system of claim 9 wherein said method obtaining said association of said transaction and said lock state further comprises a method comparing said lock state retrieved from said data cache with said bitmap value and producing a second test result.

11. A system comprising:

a processor;

a memory coupled to said processor;

object code executed by said processor for managing access to a plurality of resources, said object code comprising;

a method obtaining a request from a transaction to lock a resource; and

a method obtaining an association of said transaction and a lock state related to said resource;

wherein said method obtaining said association of said transaction and said lock state further comprises a method comparing said lock state and a bitmap value and producing a first test result.

12. The system of claim 11 wherein said method obtaining said association of said transaction and said lock state further comprises a method calling a lock manager if at least one of said first test result and a second test result indicates a failure.

13. A computer program product comprising:

a computer usable medium having computer readable code embodied therein for managing access to a plurality of resources, aid computer program product comprising;

computer readable code configured to cause a computer to obtain a request from a transaction to lock a resource; and

computer readable code configured to cause a computer to obtain an association of said transaction and a lock state related to said resource;

wherein said computer readable code configured to cause a computer to obtain said association of said transaction and said lock state further comprises computer readable code configured to cause a computer to obtain a pointer from said transaction to said lock state.

14. The computer program product of claim 13 wherein said computer readable code configured to cause a computer to obtain said association of said transaction and said lock state further comprises computer readable code configured to cause a computer to obtain said lock sate from a data cache if a first test result indicates a failure.

15. A computer program product comprising:

a computer usable medium having computer readable code embodied therein for managing access to a plurality of resources, aid computer program product comprising;

computer readable code configured to cause a computer to obtain a request from a transaction to lock a resource; and

computer readable code configured to cause a computer to obtain an association of said transaction and a lock state related to said resource;

wherein said computer readable code configured to cause a computer to obtain said association of said transaction and aid lock state further comprises computer readable code configured to cause a computer to compute a bitmap value utilizing said transaction and said lock state.

16. The computer program product of claim 15 wherein said computer readable code configured to cause a computer to obtain said association of said transaction and said lock state further comprises computer readable code configured to cause a computer to compare said lock state retrieved from said data cache with said bitmap value and produce a second test result.

17. A computer program product comprising:

a computer usable medium having computer readable code embodied therein for managing access to a plurality of resources, aid computer program product comprising;

computer readable code configured to cause a computer to obtain a request from a transaction to lock a resource; and

computer readable code configured to cause a computer to obtain an association of said transaction and a lock state related to said resource;

wherein said computer readable code configured to cause a computer to obtain said association of said transaction and said lock state further comprises computer readable code configured to cause a computer to compare said lock state and a bitmap value and produce a first test result.

18. The computer program product of claim 17 wherein said computer readable code configured to cause a computer to obtain said association of said transaction and said lock state further comprises calling a lock manager if at least one of said first test result and a second test result indicates a failure.