Tuple-based information space for data exchange between applications

• US 6,502,134 B1
• Filed: 12/09/1999
• Issued: 12/31/2002
• Est. Priority Date: 05/05/1999
• Status: Expired due to Fees

• Current Assignee: NextPage, Inc. (Proofpoint Incorporated)
• Original Assignee: NextPage, Inc. (Proofpoint Incorporated)
• Inventors: Fitzwilson, Robert C., Downs, Heather L., Makarios, Selene K.
• Primary Examiner(s): Barot, Bharat
• Application Number:
  US09/458,259
• Time in Patent Office: 1,118 Days
• Field of Search: 709/200-203, 709/217, 709/220, 709/225, 709/227-228, 709/230, 709/236, 709/242, 709/105, 707/3, 707/9, 707/10, 707/100, 707/102, 707/104, 707/200, 707/202-203
• US Class Current: 709/225
• CPC Class Codes: G06F 8/20 Software design
• CPC Class Codes: G06F 9/54 Interprogram communication
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• 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 67/289 Intermediate processing functionally located close to the data consumer application, e.g. in same machine, in same home or in same sub-network
• 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 707/99933 Query processing, i.e. searching

Abstract

A mechanism for providing application-layer information persistence and exchange is provided. For an exemplary embodiment, an information space is constructed to span a group of one or more server systems. The information space is based on the tuple-space paradigm first introduced for the Linda coordination model. A coordination entity manages storage of tuples within the information space. Applications access tuples by consulting a local cache of known tuple locations. If the location of a tuple is known, access is directed to the known location. If the location is unknown, the coordination is queried to determine the correct tuple location. If a tuple has moved, the previously storing server generates a re-route exception. This causes the accessing application to query the coordination entity, retry the access, and update the local cache.

Claims

1. A method for information exchange and persistence, the method comprising the steps of:

providing an information space distributed across multiple servers on a computer network for the distributed storage of tuples across the multiple servers; and

providing a coordination entity, the coordination entity configured to provide storage location information of a tuple stored on a first server to a second server over the computer network in response to a request for the storage location information of the tuple.

2. A method as recited in claim 1 wherein the information space is subdivided into subspaces and wherein the method further comprises a step of maintaining a cache of known tuple locations.

3. A method as recited in claim 2 wherein the coordination entity is configured to supply the subspace of a tuple when the location of that tuple is not included in the cache.

4. A method as recited in claim 2 wherein the coordination entity is configured to select the storage location of each tuple.

5. A method as recited in claim 2 further comprising transmitting a re-route exception in response to a request to access a tuple at a location other than that currently selected by the coordination entity.

6. A method as recited in claim 2, wherein each cache is located at one of the servers.

7. A method for exchanging information between applications, the method comprising the steps of:

requesting, by a client application, the storage of a tuple in an information space distributed across multiple servers on a computer network for the distributed storage of tuples across a computer network;

receiving the request for the storage of a tuple in an information space from the client application at a proxy server;

transmitting a coordination entity request from the proxy server to the coordination entity over the computer network;

selecting, by a coordination entity, at least one of the servers for storage of the tuple.

8. A method as recited in claim 7 further comprising the steps of:

searching for the tuple location in a cache of known tuple locations;

requesting the tuple location from the coordination entity if the location of the tuple is not included in the cache; and

accessing the tuple at the location retrieved from the cache or the coordination entity.

9. A method as recited in claim 8 further comprising:

adding the location retrieved from the coordination entity to the cache of known tuple locations.

10. A method as recited in claim 8 further comprising the steps:

receiving a re-route exception; and

requesting the tuple location from the coordination entity in response to receiving the re-route exception.

11. A method as recited in claim 10 further comprising:

adding the location retrieved from the coordination entity to the cache of known tuple locations.

12. A method as recited in claim 8 wherein the step of accessing is performed using remote method invocation (RMI).

13. A method as recited in claim 7 wherein the coordination entity performs the step of selecting in a way that load balances the information space.

14. A method for information exchange and persistence, the method comprising:

requesting, by a client application, a stored tuple by transmitting a client request from a client device, over a computer network, to a first server;

determining by the first server whether a storage location associated with the stored tuple is stored at the first server;

forwarding the client request by the first server over the computer network to a server associated with the storage location if the first server determines that the storage location is stored at the first server;

transmitting a query to a coordination entity by the first server if the first server determines that the storage location is not stored at the first server;

receiving a query result from the coordination entity at the first server, the query result including storage location information associated with the stored tuple;

using the query result by the first server to request the stored tuple from a server associated with the storage location.

15. The method of claim 14, further comprising storing at the first server the storage location information associated with the stored tuple as received in the query result.

16. The method of claim 14, further comprising receiving a re-route exception from server associated with the server associated with the storage location, the re-route exception causing the first server to transmit a query to the coordination entity.