AUTOMATED DATA CONVERSION AND ROUTE TRACKING IN DISTRIBUTED DATABASES

• US 20100094882A1
• Filed: 10/09/2008
• Published: 04/15/2010
• Est. Priority Date: 10/09/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Lee, Adrian
• Granted Patent: US 8,301,583 B2
• Time in Patent Office: Days
• US Class Current: 707/755
• CPC Class Codes: G06F 16/2471 Distributed queries
• CPC Class Codes: G06F 16/258 Data format conversion from or to a database

Abstract

A determination is made as to whether a data type associated with a received logical table definition associated with a database query within a distributed database system differs from a data type associated with a local logical table definition. A data conversion is performed on data retrieved from a locally-stored physical table referenced by the local logical table definition in response to determining that the data types differ. Local data conversion information is created identifying the data conversion performed on the retrieved data in response to performing the data conversion. At least one of the retrieved data and the converted data with the created local data conversion information is forwarded to at least one of a distributed database node and an application-level module. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.

Claims

1. A method, comprising:

determining whether a data type associated with a received logical table definition associated with a database query within a distributed database system differs from a data type associated with a local logical table definition;

performing a data conversion on data retrieved from a locally-stored physical table referenced by the local logical table definition in response to determining that the data type associated with the received logical table definition differs from the data type associated with a local logical table definition;

creating local data conversion information identifying the data conversion performed on the retrieved data in response to performing the data conversion; and

forwarding at least one of the retrieved data and the converted data with the created local data conversion information to at least one of a distributed database node and an application-level module.

2. The method of claim 1, where performing the data conversion on the retrieved data further comprises at least one or promoting a data type associated with the retrieved data to the data type associated with the received logical table definition, demoting a data type associated with the retrieved data to the data type associated with the received logical table definition, and casting a data type associated with the retrieved data to the data type associated with the received logical table definition.

3. The method of claim 1, where creating the local data conversion information identifying the data conversion performed on the retrieved data in response to performing the data conversion further comprises adding a node identifier to the local data conversion information.

4. The method of claim 1, further comprising determining whether the data conversion performed on the retrieved data results in a loss of precision associated with the converted data.

5. The method of claim 4, where creating the local data conversion information further comprises adding local conversion precision loss tracking information to the local data conversion information in response to determining that the data conversion performed on the retrieved data results in a loss of precision associated with the converted data.

6. The method of claim 1, further comprising:

receiving remote data and remote data conversion information in association with the received logical table definition, where the remote data conversion information identifies at least one data conversion operation performed on the received remote data by at least one other node within the distributed database system; and

performing a data conversion on the received remote data in response to determining that the data type associated with the received logical table definition differs from the data type associated with a local logical table definition.

7. The method of claim 6, where creating the local data conversion information identifying the data conversion performed on the retrieved data in response to performing the data conversion further comprises appending the created local data conversion information to the received remote data conversion information.

8. The method of claim 7, further comprising responding to the database query with at least one of the retrieved data and the converted data with the created local data conversion information, the received remote data conversion information with the appended local data conversion information, and at least one of the received remote data and the converted remote data to the at least one of the distributed database node and the application-level module.

9. The method of claim 6, further comprising:

determining whether the received remote data conversion information comprises remote conversion precision loss tracking information;

determining whether the data conversion performed on the received remote data results in a loss of precision that is larger than a configured precision loss tolerance based upon the received remote conversion precision loss tracking information; and

rejecting the received remote data in response to determining that the data conversion performed on the received remote data is larger than the configured precision loss tolerance.

10. The method of claim 6, further comprising identifying preferred routing based upon the received remote data conversion information.

11. A system, comprising:

a memory adapted to store data conversion and route tracking information; and

a processor programmed to;

determine whether a data type associated with a received logical table definition associated with a database query within a distributed database system differs from a data type associated with a local logical table definition;

perform a data conversion on data retrieved from a locally-stored physical table referenced by the local logical table definition in response to determining that the data type associated with the received logical table definition differs from the data type associated with a local logical table definition;

create local data conversion information identifying the data conversion performed on the retrieved data in response to performing the data conversion;

store the local data conversion information to the memory; and

forward at least one of the retrieved data and the converted data with the created local data conversion information to at least one of a distributed database node and an application-level module.

12. The system of claim 11, where the processor is further programmed to at least one or promote a data type associated with the retrieved data to the data type associated with the received logical table definition, demote a data type associated with the retrieved data to the data type associated with the received logical table definition, and cast a data type associated with the retrieved data to the data type associated with the received logical table definition.

13. The system of claim 11, where the processor is further programmed to add a node identifier to the local data conversion information.

14. The system of claim 11, where the processor is further programmed to determine whether the data conversion performed on the retrieved data results in a loss of precision associated with the converted data.

15. The system of claim 14, where the processor is further programmed to add local conversion precision loss tracking information to the local data conversion information in response to determining that the data conversion performed on the retrieved data results in a loss of precision associated with the converted data.

16. The system of claim 11, where the processor is further programmed to:

receive remote data and remote data conversion information in association with the received logical table definition, where the remote data conversion information identifies at least one data conversion operation performed on the received remote data by at least one other node within the distributed database system;

perform a data conversion on the received remote data in response to determining that the data type associated with the received logical table definition differs from the data type associated with a local logical table definition; and

append the created local data conversion information to the received remote data conversion information.

17. The system of claim 16, where the processor is further programmed to identify preferred routing based upon the received remote data conversion information.

18. The system of claim 17, where the processor is further programmed to respond to the database query with at least one of the retrieved data and the converted data with the created local data conversion information, the received remote data conversion information with the appended local data conversion information, and at least one of the received remote data and the converted remote data to the at least one of the distributed database node and the application-level module.

19. The system of claim 16, where the processor is further programmed to:

determine whether the received remote data conversion information comprises remote conversion precision loss tracking information;

determine whether the data conversion performed on the received remote data results in a loss of precision that is larger than a configured precision loss tolerance based upon the received remote conversion precision loss tracking information; and

reject the received remote data in response to determining that the data conversion performed on the received remote data is larger than the configured precision loss tolerance.

20. A system comprising:

a memory adapted to store data conversion and route tracking information; and

a processor programmed to;

determine whether a data type associated with a received logical table definition associated with a database query within a distributed database system differs from a data type associated with a local logical table definition;

perform a data conversion on data retrieved from a locally-stored physical table referenced by the local logical table definition in response to determining that the data type associated with the received logical table definition differs from the data type associated with a local logical table definition;

create local data conversion information identifying the data conversion performed on the retrieved data in response to performing the data conversion;

add a node identifier to the local data conversion information;

determine whether the data conversion performed on the retrieved data results in a loss of precision associated with the converted data;

add local conversion precision loss tracking information to the local data conversion information in response to determining that the data conversion performed on the retrieved data results in a loss of precision associated with the converted data;

store the local data conversion information to the memory; and

forward at least one of the retrieved data and the converted data with the created local data conversion information to at least one of a distributed database node and an application-level module.