Apparatus, method and computer program for providing arbitrary locking requesters for controlling concurrent access to server resources

• US 6,052,731 A
• Filed: 12/08/1997
• Issued: 04/18/2000
• Est. Priority Date: 07/08/1997
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Holdsworth, Simon Antony James, Houston, Iain Stuart Caldwell
• Primary Examiner(s): Rinehart, Mark H.
• Assistant Examiner(s): Thompson, Marc D.
• Application Number:
  US08/986,972
• Time in Patent Office: 862 Days
• Field of Search: 709/203, 709/226, 709/229, 710/40, 710/200, 707/8
• US Class Current: 709/229
• 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

A server concurrency control technique for use in a client/server computing system where a client sends a request to a server for access to a server resource involves receiving client requests of a plurality of lock requester types at a lock requester interface; comparing each of said requests against a lock requester set which has a lock requester type representation corresponding to a lock requester type of previously received client requests which are presently holding locks to server resources; and as a result of the comparing step, determining whether a newly received client request conflicts with previously received client requests which are currently holding locks to server resources.

Claims

1. A server concurrency control apparatus for use in a client/server computing system where a client sends a request to a server for access to a server resource, said apparatus comprising:

a lock requester interface having an input where client requests are received, said client requests being of a plurality of lock requester types; and

a lock requester set receiving as an input an output of said lock requester interface and having a lock requester type representation corresponding to each lock requester type of previously received client requests which are presently holding locks to server resources.

2. The apparatus of claim 1 wherein each of said lock requester type representations contains logic for determining whether a newly received request conflicts with the request corresponding to the lock requester representation.

3. A server concurrency control method for use in a client/server computing system where a client sends a request to a server for access to a server resource, said method comprising steps of:

receiving client requests of a plurality of lock requester types at a lock requester interface;

comparing each of said requests against a lock requester set which has a lock requester type representation corresponding to a lock requester type of previously received client requests which are presently holding locks to server resources; and

as a result of the comparing step, determining whether a newly received client request conflicts with previously received client requests which are currently holding locks to server resources.

4. The method of claim 3 further including the step of:

if the lock requester type of a newly received request is different from the lock requester type corresponding to the lock requester type representations of said lock requester set, adding a new lock requester type representation to the set corresponding to the newly received request.

5. The method of claim 3 wherein said lock requester type representations are lock requester type objects.

6. The method of claim 5 wherein said determining step involves invoking a method on each lock requester type object of said set.

7. A computer program product stored on a computer readable medium for performing server concurrency control for use in a client/server computing system where a client sends a request to a server for access to a server resource, said program product comprising program code elements for performing the functions of:

receiving client requests of a plurality of lock requester types at a lock requester interface;

comparing each of said requests against a lock requester set which has a lock requester type representation corresponding to a lock requester type of previously received client requests which are presently holding locks to server resources; and

as a result of the comparing step, determining whether a newly received client request conflicts with previously received client requests which are currently holding locks to server resources.