System and method for flushing bean cache

• US 20030051102A1
• Filed: 08/05/2002
• Published: 03/13/2003
• Est. Priority Date: 07/16/2001
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: BEA Systems Incorporated (Oracle Corporation)
• Inventors: Jacobs, Dean Bernard, Woollen, Rob, White, Seth
• Granted Patent: US 6,918,013 B2
• Time in Patent Office: Days
• US Class Current: 711/145
• CPC Class Codes: G06F 16/2315 Optimistic concurrency control
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: G06F 16/9574 of access to content, e.g. by caching
• CPC Class Codes: G06Q 20/04 Payment circuits
• CPC Class Codes: G06Q 20/389 Keeping log of transactions for guaranteeing non-repudiation of a transaction
• CPC Class Codes: G07F 19/201 Accessories of ATMs
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• CPC Class Codes: H04L 67/56 Provisioning of proxy services store-and-forward switching systems in data switching networks H04L12/54
• CPC Class Codes: H04L 67/5682 Policies or rules for updating, deleting or replacing the stored data
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users

Abstract

Servers in a network cluster can each store a copy of a data item in local cache, providing read access to these copies through read-only entity beans. The original data item in the database can be updated through a read/write entity bean one of the cluster servers. That cluster server has access to an invalidation target, which contains identification information relating to copies of the data item stored on servers in the cluster. Once the read/write bean updates the data item in the database, an invalidate request can be sent or multicast to all cluster members, or to any read-only bean or server contained in the invalidation target. Each server or read-only bean receiving the request knows to drop any copy of the data item in local cache, and can request a current copy of the data item from the database.

Claims

1. A method for updating a cached copy of a data item in a database, comprising:

storing a copy of a data item on a server, the data item being stored in a database;

generating a read-only bean to provide read access to the copy and storing identification information relating to the read-only bean;

generating a read/write bean to provide read and write access to the data item in the database and updating the data item using the read/write bean; and

sending an invalidate request to the read-only bean using the identification information so the copy of the data item can be deleted.

2. A method according to claim 1, wherein:

storing a copy of a data item stores the copy in cache on a first server.

3. A method according to claim 2, wherein:

generating a read-only bean generates the read-only bean on the first server; and

generating a read/write bean generates the read/write bean on a second server.

4. A method according to claim 3, wherein:

sending an invalidate request sends the request from the second server containing the read/write bean to the first server containing the read-only bean.

5. A method according to claim 1, wherein:

generating a read-only bean and storing identification information stores the identification information as a tag in an XML document.

6. A method according to claim 1, wherein:

sending an invalidate request to the read-only bean further involves multicasting the request to any read-only bean storing a copy of the data item as identified by the identification information.

7. A method according to claim 1, wherein:

sending an invalidate request to the read-only bean further involves multicasting the request to any member of a cluster, the server being a member of the cluster.

8. A method according to claim 7, further comprising:

periodically multicasting the invalidate request across the cluster.

9. A method according to claim 1, wherein:

sending an invalidate request to the read-only bean occurs by a point-to-point connection.

10. A method according to claim 1, wherein:

sending an invalidate request involves multicasting a request containing a version number.

11. A method according to claim 1, further comprising:

including a version identifier in the invalidate request.

12. A method according to claim 11, further comprising:

determining whether an invalidate request for the read-only bean was missed by checking the version identifier; and

requesting that an invalidate message be resent to the read-only bean if the read-only bean missed an invalidate request.

13. A method according to claim 1, further comprising:

storing recent invalidate requests.

14. A method according to claim 1, further comprising:

collecting information for multiple updates and batching the update information into one invalidate request.

15. A method for updating a cached copy of a data item, comprising:

storing a copy of a data item on a server in a cluster, the data item being stored in a network database;

updating the data item in the network database;

sending an invalidate request to a read-only bean, the read-only bean providing the cluster with read access to the copy; and

deleting the copy of the data item from the server in response to the invalidate request.

16. A method for updating a cached copy of a data item, wherein:

storing a copy of a data item stores the copy on a first server in the cluster, the read-only bean being stored on a second server.

17. A method for updating a cached copy of a data item, comprising:

storing a copy of a data item on a server in a cluster, the data item being stored in a cluster database and having a state;

providing the cluster with read access to the copy through a read-only bean on the server;

setting a timeout period for the read-only bean; and

reading the state of the data item in the cluster database at the end of the timeout period and updating the copy of the data item.

18. A system for updating cached copies of a data item in a cluster, comprising:

a first cached copy of the data item on a first server in the cluster;

a first read-only bean allowing read access to the first cached copy;

a second cached copy of the data item on a second server in the cluster;

a second read-only bean allowing read access to the second cached copy; and

a read/write bean allowing write access to the data item, the read/write bean programmed to send an invalidation request to the first and second read-only beans when the read/write bean updates the data item.

19. A system according to claim 18, further comprising:

a database adapted to contain the data item.

20. A system according to claim 18, wherein:

the first read-only bean has an interface allowing the first cached copy of the data item to be deleted; and

the second read-only bean has an interface allowing the second cached copy of the data item to be deleted.

21. A system according to claim 18, wherein:

each of the first and second read-only beans is adapted to request the resending of the invalidation request if the request was not received.

22. A system according to claim 21, wherein:

each of the first and second read-only beans is adapted to read the data item if unable to obtain a resending of the invalidation request.

23. A system according to claim 18, further comprising:

an invalidation target containing the identity of each read-only bean in the cluster caching a copy of the data item.

24. A system according to claim 23, wherein:

the invalidation target further contains the identity of the read/write bean.

25. A system according to claim 23, wherein:

the read/write bean is adapted to examine the invalidation target in order to send an invalidation request to each read-only bean caching a copy of the data item.

26. A system according to claim 18, wherein:

each of the first and second read only beans is further adapted to read a new copy of the data item after processing an invalidation request.

27. A system for updating cached copies of a data item, comprising:

a first server containing a first cached copy of the data item, the first server containing a first read-only bean allowing read access to the first cached copy; and

a second server containing a second cached copy of the data item, the second server containing a read/write bean and a second read-only bean, the second read-only bean allowing read access to the second cached copy, the read/write bean allowing write access to the data item, the read/write bean adapted to send an invalidation request to the first and second read-only beans when the read/write bean updates the data item in the data storage medium.

28. A system according to claim 27, wherein:

the first read-only bean is adapted to delete the first cached copy of the data item and the second read-only bean is adapted to delete the second cached copy of the data item in response to the invalidation. request.

29. A system for updating cached copies of a data item, comprising:

a first read-only bean allowing read access to a first cached copy of the data item;

a second read-only bean allowing read access to a second cached copy of the data item; and

a read/write bean allowing write access to the data item, the read/write bean adapted to send an invalidation request to the first and second read-only beans when the read/write bean updates the data item.

30. A system for updating cached copies of a data item, comprising:

a first server containing a first cached copy of the data item, the first server containing a read/write bean and a first read-only bean allowing read access to the first cached copy, the read/write bean allowing write access to the data item and adapted to send an invalidate request to the first read-only bean when the read/write bean updates the data item; and

a second server containing a second cached copy of the data item, the second server containing a second read-only bean allowing read access to the second cached copy, the first read-only bean capable of sending a request to the second server to delete the second cached copy.

31. A system for updating cached copies of a data item, comprising:

a first server containing a first cached copy of the data item, the first server containing a read/write bean and a first read-only bean, the read/write bean allowing write access to the data item in the data storage medium, the first read-only bean allowing read access to the first cached copy, the first read-only bean containing a timeout value specifying how often the first server update the cached copy of the data item; and

a second server containing a second cached copy of the data item, the second server containing a second read-only bean allowing read access to the second cached copy, the second read-only bean containing a timeout value specifying how often the first server update the cached copy of the data item.

32. A system for updating cached copies of a data item in a network cluster, comprising:

a database table containing a data item;

a client adapted to make requests to the network cluster;

a first server in the network cluster containing a first cached copy of the data item, the first server containing a read-only entity bean allowing read access to the first cached copy; and

a second server in the network cluster containing a second cached copy of the data item, the second server containing a read/write entity bean and a second read-only entity bean, the second read-only entity bean allowing read access to the second cached copy, the read/write entity bean allowing write access to the data item in the database table and containing identification information for the first and second read-only entity beans, the read/write entity bean adapted to send an invalidation request to the first and second read-only entity beans when the read/write entity bean updates the data item in the database table in response to a request from the client.

33. A computer-readable medium, comprising:

means for storing a copy of a data item on a server, the data item being stored in a database;

means for generating a read-only bean to provide read access to the copy and storing identification information relating to the read-only bean;

means for generating a read/write bean to provide read and write access to the data item in the database and updating the data item using the read/write bean; and

means for sending an invalidate request to the read-only bean using the identification information so the copy of the data item can be deleted.

34. A computer program product for execution by a server computer for cached copies of a data item in a network cluster, comprising:

computer code that can store a copy of a data item on a server, the data item being stored in a database;

computer code that can generate a read-only bean to provide read access to the copy and storing identification information relating to the read-only bean;

computer code that can generate a read/write bean to provide read and write access to the data item in the database and updating the data item using the read/write bean; and

computer code that can send an invalidate request to the read-only bean using the identification information so the copy of the data item can be deleted.

35. A system for updating a data item on a network, comprising:

means for storing a copy of a data item on a server, the data item being stored in a database;

means for generating a read-only bean to provide read access to the copy and storing identification information relating to the read-only bean;

means for generating a read/write bean to provide read and write access to the data item in the database and updating the data item using the read/write bean; and

means for sending an invalidate request to the read-only bean using the identification information so the copy of the data item can be deleted.

36. A computer system comprising:

a processor;

object code executed by said processor, said object code configured to;

store a copy of a data item on a server, the data item being stored in a database;

generate a read-only bean to provide read access to the copy and storing identification information relating to the read-only bean;

generate a read/write bean to provide read and write access to the data item in the database and updating the data item using the read/write bean; and

send an invalidate request to the read-only bean using the identification information so the copy of the data item can be deleted.

37. A system for updating a data item in a server cluster, comprising:

a network client capable of making a request over the network;

a network database for storing a data item and providing access to that data item over the network; and

a network server for receiving the request from said network client and processing the request, said network server storing a local copy of the data item to be used in processing the request, the network server containing a read/write bean and a read-only bean, the read-only bean allowing read access to the local copy, the read/write bean allowing write access to the data item in the network database and containing identification information for the read-only bean, the read/write bean adapted to send an invalidation request to the read-only bean on the network server and any read-only bean on any other server in the server cluster when the read/write bean updates the data item in the network database.

38. A system for updating a data item in a server cluster, comprising:

a plurality of network clients, each client being capable of making a request over the network;

at least one network database for storing a data item and providing access to that data item over the network; and

a plurality of network servers, each network server being capable of receiving a request from said plurality of network clients and processing the request, each network server capable of storing a copy of the data item in local cache and capable of storing a read-only bean for providing access to the copy of the data item to be used in processing a request from one of the network clients, one of said plurality of network servers containing a read/write bean allowing write access to the data item in the network database and having access to identification information for each read-only bean, the read/write bean being programmed to send an invalidation request to each read-only bean when the read/write bean updates the data item in the network database such that each read-only bean can delete a copy of the data item in local cache.