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Method to select an efficient access path to a remote database

IP.com Disclosure Number: IPCOM000033105D
Original Publication Date: 2004-Nov-26
Included in the Prior Art Database: 2004-Nov-26
Document File: 1 page(s) / 9K

Publishing Venue

IBM

Abstract

Database federation provides users with a virtual data warehouse, without necessarily moving any of the data. A virtual table on the federated database is used to let the users access to remote data sources in heterogeneous database environment. When multiple paths which lead a user to one and the same data source exist in the environment above, this invention makes it possible to identify the shortest path. The shortest path is selected by checking the virtualization index, which represents the number of the virtual tables on each path.

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Method to select an efficient access path to a remote database

As information technology advances and network bandwidth is getting higher, a configuration of distributed database system is getting more complex than before. Since a user can now access to data on a remote data source per table by using database federation technology, a user sometimes access to data on a remote data source which are stored on the different server. In such a database federation environment, it happens that multiple paths to access to the same data source are defined.

The response time to get data from a target table depends on the path and is heavily affected by the number of virtual tables which exist between a client and the target data source. This invention minimize the response time by choosing a path where a virtualization index is smallest. This is realized by the procedure below.

1. Create a virtual table to access to a target table.
2. Check whether the target tables is a virtual table or not.

If the target table is a virtual table, add one to a virtualization index associated with the target table. If not, set one to a virtualization index associated with the newly created virtual table.
3. Store the virtualization index into a system catalog with the information on the new virtual table.

Virtualization Index = Target's Virtualization Index +1

Create a virtual table to access to a target table

Is the target table a virtual table?

       No Yes

Virtualization Index = 1

Record the ind...