Claims
- 1. A method for improving access concurrency to information stored in at least one table in a relational database system comprising the steps of:
(a) providing a data cache comprising a plurality of cache entries, wherein each cache entry comprises a first data item, a second data item, and a cache entry state; (b) retrieving from the at least one table and storing in a cache entry's first data item a representation of committed information for a user; and (c) retrieving from the at least one table and storing in the cache entry's second data item a representation of changes applied to the committed information, but not yet committed in the database system.
- 2. The method of claim 2, further comprising the steps of:
(d) receiving a requesting database control statement from an agent to access information in the cache entry; and (e) permitting the agent access to the cache entry based on the cache entry state and the requesting control statement.
- 3. The method of claim 2, wherein the permitting step (e) comprises:
(e1) if the requesting control statement modifies the information stored in the cache entry, allowing the agent access to the second data item.
- 4. The method of claim 2, wherein the first data item represents authorization information for the user, and the second data item represents changes applied to the authorization information made by the execution of a grant statement or a revoke statement prior to the statement being committed in the database system.
- 5. The method of claim 4, wherein the permitting step (e) comprises:
(e1) if the requesting control statement does not modify the authorization information stored in the cache entry and the cache entry state indicates that the cache entry is subject to a grant statement operation, allowing the agent access to the first data item.
- 6. The method of claim 4, wherein the cache entry state is one of a VALID, VALID_RSVD, NOT_LOADED, NOT_LOADED_RSVD, and NOT_LOADED_GRIP state.
- 7. The method of claim 4, wherein the first data item is a consolidated representation of authorization information for a grantee and grantee type pair stored in the at least one table in the database system.
- 8. The method of claim 1, wherein the first data item is a bitmap and the second data item is a bitmap.
- 9. The method of claim 2, wherein the database system is an SQL database system and the database control statements are SQL statements.
- 10. A computer readable medium containing program instructions for improving access concurrency to information stored in at least one table in a relational database system, comprising the instructions for:
(a) providing a data cache comprising a plurality of cache entries, wherein each cache entry comprises a first data item, a second data item, and a cache entry state; (b) retrieving from the at least one table and storing in a cache entry's first data item a representation of committed information for a user; and (c) retrieving from the at least one table and storing in the cache entry's second data item a representation of changes applied to the committed information, but not yet committed in the database system.
- 11. The computer readable medium of claim 10, further comprising the instructions for:
(d) receiving a requesting database control statement from an agent to access information in the cache entry; and (e) permitting the agent access to the cache entry based on the cache entry state and the requesting control statement.
- 12. The computer readable medium of claim 11, wherein the permitting instruction (e) comprises:
(e1) if the requesting control statement modifies the information stored in the cache entry, allowing the agent access to the second data item.
- 13. The computer readable medium of claim 11, wherein the first data item represents authorization information for the user, and the second data item represents changes applied to the authorization information made by the execution of a grant statement or a revoke statement prior to the statement being committed in the database system.
- 14. The computer readable medium of claim 13, wherein the permitting step (e) comprises:
(e1) if the requesting control statement does not modify the authorization information stored in the cache entry and the cache entry state indicates that the cache entry is subject to a grant statement operation, allowing the agent access to the first data item.
- 15. The computer readable medium of claim 13, wherein the cache entry state is one of a VALID, VALID_RSVD, NOT_LOADED, NOT_LOADED_RSVD, and NOT_LOADED_GRIP state.
- 16. The computer readable medium of claim 13, wherein the first data item is a consolidated representation of authorization information for a grantee and grantee type pair stored in the at least one table in the database system.
- 17. The computer readable medium of claim 10, wherein the first data item is a bitmap and the second data item is a bitmap.
- 18. The computer readable medium of claim 11, wherein the database system is an SQL database system and the database control statements are SQL statements.
- 19. A system for increasing access concurrency to information in a relational database system comprising:
at least one system catalog table in the database system, wherein the at least one system catalog table comprises information for a plurality of users; and a data cache in communication with the database system for storing a portion of the at least one system catalog table, the data cache comprising a plurality of cache entries, wherein each cache entry represents information for a user by a first data item, a second data item, and a cache entry state, wherein access to the first and second data items in the cache entry depends on a requesting database control statement issued by an agent and on the cache entry state.
- 20. The system of claim 19, wherein the first data item represents committed information for a user, and the second data item represents changes applied to the committed information, but not yet committed in the database system.
- 21. The system of claim 20, wherein the first data item represents authorization information for the user, and the second data item represents changes applied to the authorization information made by the execution of a grant statement or a revoke statement prior to the statement being committed in the database system.
- 22. The system of claim 21, wherein the cache entry state is one of a VALID, VALID_RSVD, NOT_LOADED, NOT_LOADED_RSVD, and NOT_LOADED_GRIP state.
- 23. The system of claim 21, wherein the first data item is a consolidated representation of authorization information for a grantee and grantee type pair stored in the at least one table in the database system.
- 24. The system of claim 19, wherein the first data item is a bitmap and the second data item is a bitmap.
- 25. The system of claim 19, wherein the database system is an SQL database system and the database control statements are SQL statements.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2,384,259 |
Apr 2002 |
CA |
|
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit under 35 USC §119 of Canadian Application No. 2,384,259, filed on Apr. 29, 2002.