Arbitration token for managing data integrity and data accuracy of information services that utilize distributed data replicas

• US 8,180,730 B2
• Filed: 11/25/2008
• Issued: 05/15/2012
• Est. Priority Date: 11/25/2008
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Thakore, Arun Kumar
• Primary Examiner(s): Ng, Amy
• Application Number:
  US12/277,716
• Publication Number:
  US 20100131468A1
• Time in Patent Office: 1,267 Days
• Field of Search: 707/609, 707/610, 707/615, 707/618, 707/626, 707/633, 707/634
• US Class Current: 707/618
• CPC Class Codes: G06F 16/2365 Ensuring data consistency and integrity

Abstract

Illustrative embodiments present a computer-implemented method for controlling update of stored data in a set of data replicas. The computer-implemented method responsive to receiving a data request from a requester, identifies a data replica to resolve the data request to form an identified data replica. The computer-implemented method transmits an update data request to a replica administration agent if the data request is an update data request, determines whether an arbitration token is present, and responsive to a determination that the arbitration token is present; a replica administration agent updates the data in the identified data replica.

Claims

1. A computer-implemented method for controlling a plurality of updates of stored data in a plurality of data replicas, the computer-implemented method comprising:

initializing an arbitration token specifying an order in which the arbitration token is to be passed to each replica administration agent in the plurality of data replicas;

responsive to receiving a data request in a memory from a requestor, identifying a data replica, that is next in line to receive the arbitration token, to resolve the data request to form an identified data replica;

transmitting an update data request to a replica administration agent of the data replica if the data request is an update data request;

determining whether the arbitration token is present in the replica administration agent of the data replica;

responsive to a determination that the arbitration token is present in the replica administration agent of the data replica, updating the data, by the replica administration agent, in the identified data replica in an amount of time permitted by the arbitration token;

transmitting an updated arbitration token to a next replica administration agent in the plurality of data replicas in an order specified in the arbitration token;

determining the order from a plurality of entries in a data replication column, each of the plurality of entries corresponding to a particular data replica of the plurality of data replicas identified in a data replica identity column, the plurality of entries indicating the order in which the arbitration token is passed between the plurality of data replicas, wherein the data replication column and the data replica identity column are in a table in the arbitration token;

responsive to a determination that the data request is an update data request, calculating the amount of time by multiplying a quality of service time delay value times a data replica weight to get a product and dividing the product by a data replica weight of a highest weighted data replica, wherein the quality of service time delay value is retrieved from a quality of service time delay column in a table and the data replica weight is retrieved from a data replica weight column in the table;

responsive to a determination that the data request is not an update data request, determining whether requested data of the data request is in a cache of the identified data replica;

responsive to a determination that the requested data is in the cache, retrieving the requested data from the cache; and

transmitting the requested data to the requestor through a communications unit.

2. The computer-implemented method of claim 1, wherein responsive to a determination that the requested data is not in the cache:

retrieving the requested data from stored data on a storage device; and

transmitting the requested data to the requestor.

3. The computer-implemented method of claim 1, further comprising:

responsive to a determination that the arbitration token is not present in the replica administration agent of the data replica, queuing the update data request in a cache.

4. The computer-implemented method of claim 1, wherein updating the data of the identified data replica further comprises:

receiving an update confirmation from the replica administration agent;

forwarding the update confirmation to the requestor;

updating the arbitration token to form the updated arbitration token; and

broadcasting all written updates to all replica administration agents.

5. The computer-implemented method of claim 4, wherein updating the arbitration token further comprises:

receiving the quality of service time delay value;

assigning a data replica update order;

assigning data replica weight; and

determining the data replica weight of the highest weighted data replica.

6. The computer-implemented method of claim 1, wherein updating the data of the identified data replica further comprises:

determining whether all write requests completed in the amount of time;

responsive to completion of all write requests completed in the amount of time, decrementing a data replica weight; and

responsive to non-completion of all write requests completed in the amount of time, incrementing the data replica weight.

7. A data processing system for controlling update of stored data in a plurality of data replicas, the data processing system comprising:

a bus;

a memory connected to the bus, wherein the memory contains computer-executable instructions;

a processor unit, connected to the bus, wherein the processor unit executes the computer-executable instructions to direct the data processing to;

initialize an arbitration token specifying an order in which the arbitration token is to be passed to each replica administration agent in the plurality of data replicas;

responsive to receiving a data request from a requestor, identify a data replica to resolve the data request to form an identified data replica;

transmit an update data request to a replica administration agent if the data request is an update data request;

determine whether the arbitration token is present in the replica administration agent of the data replica; and

responsive to a determination that the arbitration token is present in the replica administration agent of the data replica, update the data in the identified data replica by the replica administration agent in an amount of time permitted by the arbitration token; and

transmitting an updated arbitration token to a next replica administration agent in the plurality of data replicas in the order specified in the arbitration token;

determining the order from a plurality of entries in a data replication column, each of the plurality of entries corresponding to a particular data replica of the plurality of data replicas identified in a data replica identity column, the plurality of entries indicating the order in which the arbitration token is passed between the plurality of data replicas, wherein the data replication column and the data replica identity column are in a table in the arbitration token;

determining whether the data request is an update data request;

responsive to a determination that the data request is an update data request, calculating the amount of time by multiplying a quality of service time delay times a data replica weight to get a product and dividing the product by a data replica weight of a highest weighted data replica, wherein the quality of service time delay value is retrieved from a quality of service time delay column in the table and the data replica weight is retrieved from a data replica weight column in the table;

responsive to a determination that the data request is not an update data request, determining whether requested data of the data request is in a cache of the identified data replica;

responsive to a determination that the requested data is in the cache, retrieving the requested data from the cache; and

transmit the requested data to the requestor.

8. The data processing system of claim 7, wherein the processor unit executes the computer-executable instructions responsive to a determination that the requested data is not in the cache to direct the data processing to:

retrieve the requested data from stored data on a storage device; and

transmit the requested data to the requestor through a communications unit.

9. The data processing system of claim 7, wherein the processor unit executes the computer-executable instructions responsive to a determination that the arbitration token is not present in the replica administration agent of the data replica, to direct the data processing to queue the update data request in a cache.

10. The data processing system of claim 7, wherein the processor unit executes the computer-executable instructions to update the data of the identified data replica further comprises:

receive an update confirmation from the replica administration agent;

forward the update confirmation to the requestor;

update the arbitration token to form the updated arbitration token; and

broadcast all written updates to all replica administration agents.

11. The data processing system of claim 10, wherein the processor unit executes the computer-executable instructions to direct the data processing to update the arbitration token further comprises:

receive the quality of service time delay value;

assign a data replica update order;

assign the data replica weight; and

determine the data replica weight of the highest weighted data replica.

12. The data processing system of claim 7, wherein the processor unit executes the computer-executable instructions to direct the data processing to update the data of the identified data replica further comprises:

determine whether all write requests completed in the amount of time;

responsive to completion of all write requests completed in the amount of time, decrement a data replica weight; and

responsive to non-completion of all write requests completed in the amount of time, increment the data replica weight.

13. A computer program product for controlling update of stored data in a plurality of data replicas, the computer program product comprising:

a non-transitory computer-recordable storage medium containing computer-executable instructions stored thereon, the computer-executable instructions comprising;

computer-executable instructions for initializing an arbitration token specifying an order in which the arbitration token is to be passed to each replica administration agent in the plurality of data replicas;

computer-executable instructions responsive to receiving a data request from a requestor, for identifying a data replica to resolve the data request to form an identified data replica;

computer-executable instructions for transmitting an update data request to a replica administration agent of the data replica if the data request is an update data request;

computer-executable instructions for determining whether the arbitration token is present in the replica administration agent of the data replica;

computer-executable instructions responsive to a determination that the arbitration token is present in the replica'"'"'s administration agent of the data replica, for updating the data in the identified data replica by the replica administration agent in an amount of time permitted by the arbitration token;

computer-executable instructions for transmitting an updated arbitration token to a next replica administration agent in the plurality of data replicas in the order specified in the arbitration token;

computer-executable instructions for determining the order from a plurality of entries in a data replication column, each of the plurality of entries corresponding to a particular data replica of the plurality of data replicas identified in a data replica identity column, the plurality of entries indicating the order in which the arbitration token is passed between the plurality of data replicas, wherein the data replication column and the data replica identity column are in a table in the arbitration token;

computer-executable instructions for determining whether the data request is an update data request;

computer-executable instructions responsive to a determination that the data request is an update data request, for calculating the amount of time by multiplying a quality of service time delay times a data replica weight to get a product and dividing the product by a data replica weight of a highest weighted data replica, wherein the quality of service time delay value is retrieved from a quality of service time delay column in the table and the data replica weight is retrieved from a data replica weight column in the table;

computer-executable instructions responsive to a determination that the data request is not an update data request, for determining whether requested data of the data request is in a cache of the identified data replica;

computer-executable instructions responsive to a determination that the requested data is in the cache, for retrieving the requested data from the cache; and

computer-executable instructions for transmitting the requested data to the requestor.

14. The computer program product of claim 13, wherein computer-executable instructions responsive to a determination that the requested data is not in the cache further comprise:

computer-executable instructions for retrieving the requested data from stored data on a storage device; and

computer-executable instructions for transmitting the requested data to the requestor through a communications unit.

15. The computer program product of claim 13, further comprising;

computer-executable instructions, responsive to a determination that the arbitration token is not present in the replica administration agent of the data replica, for queuing the update data request in a cache.

16. The computer program product of claim 13, wherein computer-executable instructions for updating the data of the identified data replica further comprises:

computer executable instructions for receiving an update confirmation from the replica administration agent;

computer-executable instructions for forwarding the update confirmation to the requestor;

computer-executable instructions for updating the arbitration token to form the updated arbitration token; and

computer-executable instructions for broadcasting all written updates to all replica administration agents.

17. The computer program product of claim 13, wherein computer-executable instructions for updating the data of the identified data replica further comprises:

computer-executable instructions for determining whether all write requests completed in the amount of time;

computer-executable instructions responsive to completion of all write requests completed in the amount of time, for decrementing a data replica weight; and

computer-executable instructions responsive to non-completion of all write requests completed in the amount of time, for incrementing the data replica weight.