Java object cache server for databases

• US 20040210909A1
• Filed: 04/17/2003
• Published: 10/21/2004
• Est. Priority Date: 04/17/2003
• Status: Active Grant

• Current Assignee: Salesforce.com, Inc.
• Original Assignee: Salesforce.com, Inc.
• Inventors: Chan, Eric, Moellenhoff, Dave, Dominguez, Frank Jr.
• Granted Patent: US 7,209,929 B2
• Time in Patent Office: Days
• US Class Current: 719/316
• CPC Class Codes: H04L 67/5651 Reducing the amount or size of exchanged application data
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: Y10S 707/955 Object-oriented
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure

Abstract

A cache server is provided in a network for storing Java objects for retrieval by one or multiple application servers. Application server(s) are configured to request an object from the cache server, rather than requesting the Java object directly from a database, so as to reduce processing load on the database and free up database resources. Responsive to a request for a Java object from an application server, e.g., in an HTTP request, the cache server determines if the object is stored in memory and if so, serializes the requested object and sends the serialized object to the requesting server, e.g., in an HTTP response. The requesting server then deserializes the Java object. If the object is not stored in memory, the cache server instantiates the object (typically by requesting the object from the database), serializes the instantiated object and sends it to the requesting server. Cache coherency methods are also provided.

Claims

1. A method of providing a Java object from a cache server to a requesting system, the cache server being communicably coupled to a Java object database and one or more requesting systems, the method comprising:

receiving a request from a requesting system, the request identifying a Java object;

responsive to said request, determining whether the identified Java object is stored in the cache server; and

if the identified Java object is stored in the cache server;

serializing the identified Java object; and

sending the serialized Java object to the requesting system; and

if the identified Java object is not stored in the cache server;

instantiating the identified Java object;

serializing the instantiated Java object; and

sending the serialized Java object to the requesting system.

2. The method of claim 1, wherein instantiating includes:

requesting the identified Java object from the Java object database; and

receiving the requested Java object from the Java object database.

3. The method of claim 1, further including storing the instantiated Java object in the cache server.

4. The method of claim 1, wherein the received request is an HTTP request, and wherein sending the serialized Java object includes sending the object in an HTTP response to the requesting system.

5. The method of claim 1, further including:

receiving an invalidation request from a requesting system, said invalidation request identifying a Java object to rebuild; and

rebuilding the identified Java object responsive to receiving the invalidation request.

6. The method of claim 5, wherein rebuilding includes maintaining an original copy of the Java object being rebuilt, such that if a requesting system requests a Java object as it is being rebuilt, the server serializes and sends the original copy of the Java object.

7. The method of claim 6, wherein rebuilding includes replacing the original copy of the Java object with the rebuilt Java object after the Java object has been rebuilt.

8. The method of claim 5, further including:

receiving a second invalidation request to rebuild the Java object as the Java object is being rebuilt;

setting a flag in response to the second invalidation request; and

processing the second invalidation request after the Java object has been rebuilt.

9. The method of claim 1, further including automatically removing, from the cache server, Java objects that have not been accessed within a specified access interval.

10. The method of claim 9, wherein the access interval is user configurable.

11. The method of claim 9, further including automatically removing, from the cache server, Java objects that have not been accessed within a specified access interval in response to each request received from a requesting system.

12. The method of claim 1, further including automatically removing, from the cache server, one or more Java objects when it is determined that a specified number of Java objects are stored in the cache server.

13. The method of claim 12, wherein the specified number of Java objects is user configurable.

31. The method of claim 1, further including:

receiving an update message from a requesting system, said update message identifying a Java object to update; and

updating the identified Java object responsive to receiving the update message.

32. The method of claim 1, further including storing the serialized Java object to a disk.

38. The method of claim 1, further including storing the serialized object to a disk drive.

39. The method of claim 38, wherein the serialized Java object stored to the disk drive includes a version number, wherein objects stored in the database each include a version number, the method further including, upon a start-up of the cache server:

retrieving the version number of serialized Java object from the disk drive;

requesting the version number of the Java object from the database; and

comparing the version number of the Java object from the disk drive with the version number from the database.

40. The method of claim 39, further including storing the Java object to the cache server from the disk drive if the version numbers match.

41. The method of claim 40, wherein if the version numbers do not match, the method further includes instantiating the Java object from the database when the server receives a request from a requesting system for the Java object.

14. A Java object cache server communicably coupled to a Java object database and one or more requesting systems, the cache server comprising:

a processor; and

a memory for storing Java objects,

wherein the server is configured to;

receive a request from a requesting system, said request identifying a Java object;

determine whether the identified Java object is stored in the memory; and

if the identified Java object is stored in memory;

serialize the identified Java object; and

send the serialized Java object to the requesting system; and

if the identified Java object is not stored in memory;

instantiate the identified Java object;

serialize the instantiated Java object; and

send the serialized Java object to the requesting system.

15. The server of claim 14, wherein the server is further configured to automatically remove, from the memory, Java objects that have not been accessed within a specified access interval.

16. The server of claim 15, wherein the access interval is user configurable.

17. The server of claim 15, wherein the server is configured to automatically remove, from the memory, Java objects that have not been accessed within a specified access interval in response to each request received from a requesting system.

18. The server of claim 14, wherein the server is further configured to automatically remove Java objects from the memory when it is determined that a specified number of Java objects are stored in the memory.

19. The server of claim 18, wherein the specified number of Java objects is user configurable.

20. The server of claim 14, wherein the server is further configured to rebuild a Java object stored in the memory in response to an invalidation request from a system, said invalidation request identifying the Java object to be rebuilt.

21. The server of claim 20, wherein the server maintains an original copy of a Java object that is being rebuilt, such that if a requesting system requests a Java object as it is being rebuilt, the server is configured to serialize and send the original copy of the Java object.

22. The server of claim 21, wherein the server is configured to replace the original copy of a Java object with the rebuilt Java object after the Java object has been rebuilt.

23. The server of claim 21, wherein if a second invalidation request to rebuild a Java object is received as the Java object is being rebuild, a flag is set, and wherein the second invalidation request is processed after the Java object has been rebuilt.

33. The server of claim 14, wherein the server is further configured to update a Java object stored in the memory in response to an update message from a system, said update message identifying the Java object to be updated.

34. The server of claim 14, further including a disk drive, wherein the server is further configured to store the serialized Java object to the disk drive.

35. The system of claim 34, wherein the serialized Java object stored to the disk drive includes a version number, wherein objects stored in the database each include a version number, and wherein upon a start-up of the cache server, the cache server retrieves the version number of the serialized Java object from the disk drive, requests the version number of the object from the database and compares the version number of the Java object from the disk drive with the version number from the database.

36. The system of claim 35, wherein if the version numbers match, the Java object is stored to the cache server memory from the disk drive.

37. The system of claim 35, wherein if the version numbers do not match, when the server receives a request from the requesting system for the Java object, the server instantiates the Java object from the database.

24. A method of rebuilding a Java object in a Java object cache server, comprising:

receiving an invalidation request, said invalidation request identifying a first Java object in the cache server;

rebuilding the first Java object; and

maintaining an original copy of the first Java object in the cache server as the cache server is rebuilding the first Java object, such that the cache server is able to provide the original copy in response to a request for the first Java object as the first Java object is being rebuilt.

25. The method of claim 24, further comprising sending the original copy of the first Java object to a requesting system in response to a request for the first Java object received while the first Java object is being rebuilt.

26. The method of claim 24, further comprising:

receiving a second invalidation request identifying the first Java object, said second invalidation request being received while the first Java object is being rebuilt; and

processing the second invalidation request after the first Java object has been rebuilt.

27. The method of claim 24, further comprising:

receiving a second invalidation request identifying the first Java object, said second invalidation request being received while the first Java object is being rebuilt;

setting a flag in response to the second invalidation request; and

after the first Java object has been rebuilt, rebuilding the first Java object responsive to the flag being set and according to the second invalidation request.

28. The method of claim 24, further comprising:

receiving a plurality of second invalidation requests identifying the first Java object while the first Java object is being rebuilt;

setting a flag in response to each second invalidation request; and

processing each second invalidation request in the order received.

29. The method of claim 28, wherein for each second invalidation request, processing includes:

rebuilding the Java object according to the second invalidation request;

maintaining a copy of the Java object in the cache server as it exists before being rebuilt; and

thereafter

replacing the Java object with the rebuilt Java object.

30. The method of claim 24, further comprising after rebuilding the first Java object, replacing the original Java object in the cache server with the rebuilt Java object.