Systems and methods for query caching

• US 20050262059A1
• Filed: 10/14/2004
• Published: 11/24/2005
• Est. Priority Date: 05/21/2004
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: BEA Systems Incorporated (Oracle Corporation)
• Inventors: White, Seth
• Granted Patent: US 8,019,735 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/24552 Database cache management

Abstract

Query caching enables the caching of EJB instances at the granularity of query level. It removes the current limitation on EJB caching by allowing the result from an arbitrary query which uses, e.g., either a primary key or a non-primary key, to be stored in the in-memory cache in the container. The query languages utilized by the query can be, but are not limited to SQL and EJB-QL. The performance of an application server can be improved significantly since the result of an query called after the result an identical query has been cached earlier can be retrieved from the cache directly without accessing the underlying database again. In addition, such query caching has an advantage in performance since it can be executed implicitly by the container instead of being explicitly invoked in the application code by the user. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.

Claims

1. A system to provide query caching, comprising:

A query component capable of issuing a query to retrieve one or more instances of a class;

a query registration component capable of;

maintaining a query registry of strings of one or more queries; and

looking up the string of the query in the query registry;

a cache capable of storing the one or more instances of the class in memory; and

a cache management component capable of at least one of;

accessing a database using the query;

generating and storing a result of the query in the cache; and

retrieving the result of the query in the cache.

2. The system according to claim 1, wherein:

the class can be one of a Java bean, an Enterprise Java Bean (EJB), an interface, and a module.

3. A system to provide query caching, comprising:

an EJB query component capable of issuing a query to retrieve one or more instances of an EJB;

a query registration component capable of;

maintaining a query registry of strings of one or more queries; and

looking up the string of the query in the query registry;

a cache capable of storing the one or more instances of the EJB in memory; and

a cache management component capable of at least one of;

accessing a database using the query;

generating and storing a result of the query in the cache; and

retrieving the result of the query in the cache.

4. The system according to claim 3, wherein:

the query language used by the query can be SQL or EJB-QL.

5. The system according to claim 3, wherein:

the query is capable of using either a primary key or a non-primary key of a data entity in the database.

6. The system according to claim 3, wherein:

The EJB query component is capable of adopting either an explicit caching strategy or an implicit caching strategy.

7. The system according to claim 3, wherein:

the EJB can be an entity bean that uses read-only or optimistic concurrency control strategy.

8. The system according to claim 3, wherein:

the query registration component is capable of maintaining the query registry by inserting or deleting the string of a query in the query registry.

9. The system according to claim 3, wherein:

the query registration component is capable of looking up the string of the query by performing an exact matching between the string of the query and the string of a query in the query registry.

10. The system according to claim 3, wherein:

the database can be one of a relational database, an Oracle Database, a DB2, and a MS SQL Server.

11. The system according to claim 3, wherein:

the cache management component is further capable of at least one of;

retrieving the result of a query in the cache by its key;

selecting a query and removing its result from the cache; and

invalidating the result of a query in the cache.

12. The system according to claim 11, wherein:

the query can be selected using a least-recently-used algorithm.

13. The system according to claim 11, wherein:

the result of a query can be invalidated if a part of the result is invalid.

14. A method to provide query caching, comprising:

issuing a query to retrieve one or more instances of a class;

maintaining a query registry of strings of one or more queries;

looking up the string of the query in the query registry;

accessing a database using the query;

generating and storing a result of the query in a cache; and

retrieving the result of the query in the cache.

15. A method to provide query caching, comprising:

issuing a query to retrieve one or more instances of an EJB;

maintaining a query registry of strings of one or more queries;

looking up the string of the query in the query registry;

accessing a database using the query;

generating and storing a result of the query in a cache; and

retrieving the result of the query in the cache.

16. The method according to claim 15, wherein:

the query language used by the query can be SQL or EJB-QL.

17. The method according to claim 15, wherein:

the query is capable of using either a primary key or a non-primary key of a data entity in the database.

18. The method according to claim 15, further comprising:

adopting either an explicit caching strategy or an implicit caching strategy.

19. The method according to claim 15, further comprising:

maintaining the query registry by inserting or deleting the string of a query in the query registry.

20. The method according to claim 15, further comprising:

performing an exact matching between the string of the query and the string of a query in the query registry.

21. The method according to claim 15, further comprising at least one of:

retrieving the result of a query in the cache by its key;

selecting a query and removing its result from the cache; and

invalidating the result of a query in the cache.

22. The method according to claim 21, wherein:

the query can be selected using a least-recently-used algorithm.

23. The method according to claim 21, wherein:

the result of a query can be invalidated if a part of the result is invalid.

24. A machine readable medium having instructions stored thereon that when executed cause a system to:

issue a query to retrieve one or more instances of a class;

maintain a query registry of strings of one or more queries;

look up the string of the query in the query registry;

access a database using the query;

generate and store a result of the query in a cache; and

retrieve the result of the query in the cache.

25. A machine readable medium having instructions stored thereon that when executed cause a system to:

issue a query to retrieve one or more instances of an EJB;

maintain a query registry of strings of one or more queries;

look up the string of the query in the query registry;

access a database using the query;

generate and store a result of the query in a cache; and

retrieve the result of the query in the cache.

26. The machine readable medium of claim 25, wherein:

the query language used by the query can be SQL or EJB-QL.

27. The machine readable medium of claim 25, wherein:

the query is capable of using either a primary key or a non-primary key of a data entity in the database.

28. The machine readable medium of claim 25, further comprising instructions that when executed cause the system to:

adopt either an explicit caching strategy or an implicit caching strategy.

29. The machine readable medium of claim 25, further comprising instructions that when executed cause the system to:

maintain the query registry by inserting or deleting the string of a query in the query registry.

30. The machine readable medium of claim 25, further comprising instructions that when executed cause the system to:

perform an exact matching between the string of the query and the string of a query in the query registry.

31. The machine readable medium of claim 25, further comprising instructions that when executed cause the system to perform at least one of:

retrieving the result of a query in the cache by its key;

selecting a query and removing its result from the cache; and

invalidating the result of a query in the cache.

32. The machine readable medium of claim 31, further comprising instructions that when executed cause the system to:

select the query using a least-recently-used algorithm.

33. The machine readable medium of claim 31, further comprising instructions that when executed cause the system to:

invalidate the result of a query if a part of the result is invalid.

34. A system to provide query caching, comprising:

means for issuing a query to retrieve one or more instances of a class;

means for maintaining a query registry of strings of one or more queries;

means for looking up the string of the query in the query registry;

means for accessing a database using the query;

means for generating and storing a result of the query in a cache; and

means for retrieving the result of the query in the cache.

35. A system to provide query caching, comprising:

means for issuing a query to retrieve one or more instances of an EJB;

means for maintaining a query registry of strings of one or more queries;

means for looking up the string of the query in the query registry;

means for accessing a database using the query;

means for generating and storing a result of the query in a cache; and

means for retrieving the result of the query in the cache.

36. A computer data signal embodied in a transmission medium, comprising:

a code segment including instructions to issue a query to retrieve one or more instances of a class;

a code segment including instructions to maintain a query registry of strings of one or more queries;

a code segment including instructions to look up the string of the query in the query registry;

a code segment including instructions to access a database using the query;

a code segment including instructions to generate and store a result of the query in a cache; and

a code segment including instructions to retrieve the result of the query in the cache.

37. A computer data signal embodied in a transmission medium, comprising:

a code segment including instructions to issue a query to retrieve one or more instances of an EJB;

a code segment including instructions to maintain a query registry of strings of one or more queries;

a code segment including instructions to look up the string of the query in the query registry;

a code segment including instructions to access a database using the query;

a code segment including instructions to generate and store a result of the query in a cache; and

a code segment including instructions to retrieve the result of the query in the cache.