System and method for providing a cache that stores entity beans and employs data invalidation

• US 8,176,014 B2
• Filed: 04/06/2007
• Issued: 05/08/2012
• Est. Priority Date: 08/30/2001
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Jacobs, Dean Bernard, Woollen, Robert, White, Seth
• Primary Examiner(s): LY, CHEYNE D
• Application Number:
  US11/697,675
• Publication Number:
  US 20070192320A1
• Time in Patent Office: 1,859 Days
• Field of Search: 707/622, 707/636, 707/657, 709/203, 709/218, 711/119, 711/145, 711/163
• US Class Current: 707/657
• 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 system for caching entity beans in a cluster environment, said system comprising:

a database connected to the cluster, said database storing at least one data item; and

a server device connected to the cluster, said server device caching a plurality of entity beans, each entity bean containing a copy of said data item;

wherein the server device includes one or more read-only entity beans that allow shared access to said data item by clients such that the data item is not modified within the database as a result of the shared access, wherein each of the one or more read only entity beans located on said server device exposes an interface to invalidate the copy of said data item stored locally on the server device;

wherein the server device further includes a bean providing write access to the same data item in the database that is accessed by the one or more read-only entity beans;

wherein a deployment descriptor associated with the bean providing write access contains an invalidation target tag that identifies the one or more read-only entity beans associated with the data item, wherein the invalidation target tag in the deployment descriptor is used to invalidate the one or more read-only entity beans; and

wherein after the data item is modified in the database by using the read/write bean, the one or more read-only entity beans on the server device receive an invalidate request on the interface exposed by said read-only entity beans, wherein the server device then drops the copy of the data item stored locally in response to said invalidate request and multicasts said invalidate request to a plurality of other servers in the cluster containing a local cached copy of said data item, wherein the multicasting of the invalidate request instructs said plurality of other servers to drop the local cached copy of said data item.

2. The system of claim 1 wherein each bean in said cache has an underlying database table in said database such that each instance of said entity beans corresponds to a row in said database table.

3. The system of claim 1 wherein each read-only entity bean in said cache is associated with a timeout value.

4. The system of claim 1 wherein each entity bean can participate in relationships with other entity beans in said cache.

5. The system of claim 1 wherein each server in said cluster can drop any copy of said data item in the cache and can read in a new value from said database when necessary to serve a request.

6. The system of claim 1 wherein each entity bean is a container-managed persistence (CMP) bean and wherein each entity bean calls on the Enterprise JavaBean (EJB) load method in order to read said data item from the database.

14. The system of claim 1, wherein the one or more read-only entity beans referenced by the invalidation target tag are updated when data is requested from the bean providing write access to the copy of the data item or when a read-only bean is generated.

7. A method for caching entity beans in a cluster environment, said method comprising:

storing a copy of a data item in a read-only entity bean on at least one server in the cluster, said read-only entity bean providing read access to the copy of the data item, wherein the read-only entity bean located on said at least one server exposes an interface to invalidate the copy of said data item stored locally on the server;

providing identification information to a read/write bean enabling write access to the same data item in the database that is accessed by the read-only entity bean, said identification information relating to the read-only entity bean;

wherein a deployment descriptor associated with the bean enabling write access contains an invalidation target tag that identifies the read-only entity bean associated with the data item, wherein the invalidation target tag in the deployment descriptor is used to invalidate the read-only entity bean; and

wherein after the data item is modified in the database by using the read/write bean, the read-only entity bean on the server device receive an invalidate request on the interface exposed by said read-only entity beans, wherein the server device then drops the copy of the data item stored locally in response to said invalidate request and multicasts said invalidate request to a plurality of other servers in the cluster containing a local cached copy of said data item, wherein the multicasting of the invalidate request instructs said plurality of other servers to drop the local cached copy of said data item.

8. The method of claim 7 wherein each entity bean in said server has an underlying database table in said database such that each instance of said entity beans corresponds to a row in said database table.

9. The method of claim 7 wherein each read-only entity bean in said server is associated with a timeout value.

10. The method of claim 7 wherein each entity bean can participate in relationships with other entity beans in said server.

11. The method of claim 7 wherein each server in said cluster can drop any copy of said data item and can read in a new value from said database when necessary to serve a request.

12. The method of claim 7 wherein each entity bean is a container-managed persistence (CMP) bean and wherein each entity bean calls on the Enterprise JavaBean (EJB) load method in order to read said data item from the database.

15. The method of claim 7, wherein the read-only entity bean referenced by the invalidation target tag is updated when data is requested from the bean providing write access to the copy of the data item or when the read-only bean is generated.

13. A computer readable storage medium having object code stored thereon which when executed by one or more processors causes the one or more processors to:

store a copy of a data item in a read-only entity bean on at least one server in the cluster, said read-only entity bean providing read access to the copy of the data item, wherein the read-only entity bean located on said at least one server exposes an interface to invalidate the copy of said data item stored locally on the server;

provide identification information to a read/write bean enabling write access to the same data item in the database that is accessed by the read-only entity bean, said identification information relating to the read-only entity bean;

wherein a deployment descriptor associated with the bean enabling write access contains an invalidation target tag that identifies the read-only entity bean associated with the data item, wherein the invalidation target tag in the deployment descriptor is used to invalidate the read-only entity bean; and

wherein after the data item is modified in the database by using the read/write bean, the read-only entity bean on the server device receive an invalidate request on the interface exposed by said read-only entity beans, wherein the server device then drops the copy of the data item stored locally in response to said invalidate request and multicasts said invalidate request to a plurality of other servers in the cluster containing a local cached copy of said data item, wherein the multicasting of the invalidate request instructs said plurality of other servers to drop the local cached copy of said data item.