System and Method for Flushing Bean Cache

• US 20070192320A1
• Filed: 04/06/2007
• Published: 08/16/2007
• Est. Priority Date: 08/30/2001
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: BEA Systems Incorporated (Oracle Corporation)
• Inventors: White, Seth, Jacobs, Dean, Woollen, Robert
• Granted Patent: US 8,176,014 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 bean cache connected to the cluster, said bean cache containing a plurality of entity beans, each entity bean containing a copy of said data item;

wherein the bean cache includes at least one read-only entity bean that allows shared access to said data item by one or more clients such that the data item is not modified within the database as a result of the shared access.

2. The system of claim 1 wherein said bean cache further includes:

at least one bean residing on a server in said cluster that provides read and write access to said database.

3. The system of claim 1 wherein each entity bean in said bean 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.

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

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

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

7. 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.

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

maintaining a connection to a database by one or more network clients, said database storing a copy of a data item for access by the one or more clients;

receiving a request for said data item from the one or more clients;

generating a read-only entity bean in processing the request, said read-only entity bean providing read access to the copy of the data item and storing identification information relating to the read-only bean; and

storing said read-only entity bean in an entity bean cache.

9. The method of claim 8 wherein each entity bean in said bean 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.

10. The method of claim 8 wherein said entity bean cache further includes:

at least one bean that provides read and write access to said database.

11. The method of claim 8 wherein each read-only bean in said entity bean cache is associated with a timeout value.

12. The method of claim 8 wherein each entity bean can participate in relationships with other entity beans in said cache.

13. The method of claim 8 wherein each server in said cluster can drop any copy of said data item in the bean cache and can read in a new value from said database when necessary to serve a request.

14. The method of claim 8 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. A computer readable medium having object code stored thereon which when executed by one or more processors causes a system to:

maintain a connection to a database by one or more network clients, said database storing a copy of a data item for access by the one or more clients;

receive a request for said data item from the one or more clients;

generate a read-only entity bean in processing the request, said read-only entity bean providing read access to the copy of the data item and storing identification information relating to the read-only bean; and

store said read-only entity bean in an entity bean cache.