Data processing: database and file management or data structures – Database design – Data structure types
Reexamination Certificate
2005-09-13
2005-09-13
Metjahic, Safet (Department: 2161)
Data processing: database and file management or data structures
Database design
Data structure types
C707S793000
Reexamination Certificate
active
06944615
ABSTRACT:
In a database management system (DBMS) (60) for a database application (10) including a database (12) having a table (14, 16, 18) and a unique key index (42) having indexes (44, 46, 48) therefor, the DBMS (60) includes a data manager (64), an index manager (66), a transaction manager (62), and a lock manager (68) which restricts access to the table by assigning locks to elements thereof. In order to avoid deadlock in the database application due to the pseudo-deleted entries, the lock categories include an X-lock and a Conditional S-lock, and have lock attributes including at least a Delete attribute for the X-lock. The Conditional S-lock is compatible (granted by the lock manager) with an X-lock whose Delete attribute is NOT SET, but is not compatible (granted) with an X-lock whose Delete attribute is SET. Each index entry includes a pseudo-delete flag which is SET by the index manager (66) to indicate deletion of the indexed row. Conditional upon locating a pseudo-deleted index key corresponding to a key to be added to the index, the index manager (66) requests a Conditional S-lock on the row indexed thereby, whereby the index manager (66) verifies the Delete transaction which set the pseudo-delete flag has committed.
REFERENCES:
patent: 4914569 (1990-04-01), Levine et al.
patent: 4961134 (1990-10-01), Crus et al.
patent: 5119490 (1992-06-01), Kurose
patent: 5123104 (1992-06-01), Levine et al.
patent: 5280612 (1994-01-01), Lorie et al.
patent: 5442758 (1995-08-01), Slingwine et al.
patent: 5465328 (1995-11-01), Dievendorff et al.
patent: 5551027 (1996-08-01), Choy et al.
patent: 5809507 (1998-09-01), Cavanaugh, III
patent: 5960194 (1999-09-01), Choy et al.
patent: 6009425 (1999-12-01), Mohan
patent: 6032216 (2000-02-01), Schmuck et al.
patent: 6047285 (2000-04-01), Jacobs et al.
patent: 6070164 (2000-05-01), Vagnozzi
patent: 6105025 (2000-08-01), Jacobs et al.
patent: 6182186 (2001-01-01), Daynes
patent: 6363387 (2002-03-01), Ponnekanti et al.
patent: 2001/0047360 (2001-11-01), Huras et al.
patent: 2002/0087500 (2002-07-01), Berkowitz et al.
Technical Disclosure Bulletin: Locking Protocols for Concurrent Operations on B Trees:; Mar. 1977; pp. 3887-3889.
IBM Technical Disclosure Bulletin: “Concurrent Access of the Table Object Location Linked List”; Apr. 1993; pp. 541-544.
“Operation-Specific Locking in Balanced Structures”; Alexandros Biliris; Information Sciences An International Journal; vol. 48, No. 1, Jun. 1989; pp. 27-51.
Concurrency Control in the Interpolation-Based Grid File: M.A. Ouksel, et al.; International Conference on Database and Expert Systems Applications, 3rd, Valencia, Spain, Sep. 2-4, 1992, Proceedings of DEXA '92; pp. 237-243.
“Study of Concurrent Operations on R-Trees”; J.K. Chen, et al.; Information Sciences; vol. 98, issue 1-4, May 1997; pp. 263-300.
Hrle Namik
Teng James Zu-Chia
Fay Sharpe Fagan Minnich & McKee LLP
Goddard Brian
Metjahic Safet
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