Distributed document retrieval method and device, and distributed document retrieval program and recording medium recording the program

• US 20020161753A1
• Filed: 04/04/2002
• Published: 10/31/2002
• Est. Priority Date: 04/05/2001
• Status: Abandoned Application

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Kanno, Yuji, Inaba, Mitsuaki
• Application Number:
  US10/115,261
• Publication Number:
  US 20020161753A1
• Time in Patent Office: Days
• US Class Current: 707/3
• CPC Class Codes: G06F 16/2471 Distributed queries
• CPC Class Codes: G06F 16/93 Document management systems

Abstract

A distributed document retrieval method for performing document retrieval by plural retrieval servers that each perform document retrieval for a database storing plural documents, and an integrating retrieval server that is connected to the plural retrieval servers over communication and issues retrieval orders to the retrieval servers, wherein each retrieval server delivers statistical information created based on intermediate results obtained by retrieval operation to the integrating retrieval server, the integrating retrieval server compiles the statistical information to create global statistical information and delivers it to each retrieval server, and each retrieval server calculates scores based on the global statistical information and sends retrieval results matching retrieval conditions back to the integrating retrieval server. By the above described operation, efficient and correct ranking among retrieval documents is achieved with improved document retrieval quality.

Claims

1. A distributed document retrieval method for performing document retrieval by plural retrieval servers that each perform document retrieval for a database storing plural documents, and an integrating retrieval server that is connected to the plural retrieval servers over communication and issues retrieval orders to the retrieval servers, wherein:

each retrieval server delivers statistical information created based on intermediate results obtained by retrieval operation to the integrating retrieval server;

the integrating retrieval server compiles the statistical information to create global statistical information and delivers it to each retrieval server; and

each retrieval server calculates scores based on the global statistical information and sends retrieval results matching retrieval conditions back to the integrating retrieval server.

2. The distributed document retrieval method according to claim 1, wherein the retrieval servers hold the intermediate results obtained by the retrieval operation by themselves.

3. The distributed document retrieval method according to claim 2, wherein the retrieval servers wait for the arrival of global statistical information obtained in the integrating retrieval server within a limited time, and if said limited time elapses, processing for the retrieval request is canceled to proceed to processing for a different retrieval request.

4. The distributed document retrieval method according to claim 3, wherein the retrieval servers assign IDs to intermediate results obtained by the retrieval operation and hold the plural intermediate results by themselves, and deliver statistical information created based on the intermediate results to the integrating retrieval server along with the IDs assigned to the intermediate results.

5. The distributed document retrieval method according to claim 1, wherein:

the retrieval servers update the versions of the databases independently of each other, do not report the version updating to the integrating retrieval server each time the updating is performed, and deliver version information to the integrating retrieval server along with statistical information when retrieval operation on a subsequent retrieval request is performed; and

the integrating retrieval server automatically creates an integrated version consisting of a combination of the latest versions of the databases of the retrieval servers when said version information arrives or as required.

6. The distributed document retrieval method according to claim 5, wherein the retrieval servers, when the version of the databases is updated, unload an old version a predetermined time after a new version is loaded in the retrieval servers.

7. The distributed document retrieval method according to claim 5, wherein the integrating retrieval server, when the number of integrated versions exceeds a predetermined value, deletes the integrated versions according to a predetermined rule.

8. The distributed document retrieval method according to claim 5, wherein:

upon receipt of a retrieval request, the retrieval servers, if a version of the databases has been unloaded, delivers unload information indicating the fact to the integrating retrieval server along with statistical information; and

the integrating retrieval server, when said unload information arrives or as required, deletes pertinent integrated versions according to said unload information.

9. A distributed document retrieval device comprising plural retrieval servers that each perform document retrieval for a database storing plural documents, and an integrating retrieval server that is connected to the plural retrieval servers over communication and issues retrieval orders to the retrieval servers, wherein:

said retrieval servers each include;

retrieving means for performing retrieval operation on the databases;

means for holding intermediate results obtained as a result of said retrieval operation;

statistical information outputting means for creating and outputting statistical information from said intermediate results; and

score calculating means for giving scores to each of retrieved documents;

said integrating retrieval server includes statistical information compiling means for compiling statistical information delivered from plural retrieval servers; and

said integrating retrieval server creates global statistical information and delivers it to the retrieval servers, and the retrieval servers each calculate scores, based on said global statistical information, and send retrieval results matching retrieval conditions back to said integrating retrieval server.

10. The distributed document retrieval device according to claim 9, wherein said integrating retrieval server includes means for creating an integrated version, based on statistical information compiled by said statistical information compiling means.

11. The distributed document retrieval device according to claim 10, wherein said integrating retrieval server includes integrated version updating means for updating said integrated version, and integrated version management means for managing said integrated version.

12. The distributed document retrieval device according to claim 9, wherein said retrieval servers include retrieval result sorting means for sorting retrieval results according to a predetermined rule, based on the results of score calculating by said score calculating means.

13. The distributed document retrieval device according to claim 11, wherein:

said retrieval servers includes version updating means for updating the versions of the databases and version management means for managing versions wherein said version management means delivers version information to the integrating retrieval server along with statistical information when retrieval operation on a retrieval request is performed; and

said integrating retrieval server automatically creates an integrated version consisting of a combination of the latest versions of the databases of the retrieval servers when said version information arrives or as required.

14. The distributed document retrieval device according to claim 11, wherein said integrating retrieval server delivers integrated version information together when issuing a retrieval order to the retrieval servers.

15. A recording medium recording a distributed document retrieval program for performing document retrieval by plural retrieval servers that each perform document retrieval for a database storing plural documents, and an integrating retrieval server that is connected to the plural retrieval servers over communication and issues retrieval orders to the retrieval servers, the distributed document retrieval program comprising the steps of:

instructing each retrieval server to deliver statistical information created based on intermediate results obtained by retrieval operation to the integrating retrieval server;

instructing the integrating retrieval server to compile said statistical information to create global statistical information and deliver it to each retrieval server; and

instructing each retrieval server to calculate scores based on said global statistical information and send retrieval results matching retrieval conditions back to the integrating retrieval server.

16. A distributed document retrieval program for performing document retrieval by plural retrieval servers that each perform document retrieval for a database storing plural documents, and an integrating retrieval server that is connected to the plural retrieval servers over communication and issues retrieval orders to the retrieval servers, the distributed document retrieval program comprising the steps of:

instructing each retrieval server to deliver statistical information created based on intermediate results obtained by retrieval operation to the integrating retrieval server;

instructing the integrating retrieval server to compile said statistical information to create global statistical information and deliver it to each retrieval server; and

instructing each retrieval server to calculate scores based on said global statistical information and send retrieval results matching retrieval conditions back to the integrating retrieval server.