FAILURE TOLERANT TRANSACTION PROCESSING SYSTEM

• US 20090157757A1
• Filed: 04/03/2008
• Published: 06/18/2009
• Est. Priority Date: 11/30/2005
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Yamamoto, Guku, Hori, Hiroshi, Tai, Hideki
• Granted Patent: US 8,166,007 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/1443 Transmit or communication errors
• CPC Class Codes: G06F 11/1474 in transactions G06F16/20 takes precedence
• CPC Class Codes: G06F 11/183 by voting, the voting not being performed by the redundant components
• CPC Class Codes: G06F 11/2023 Failover techniques
• CPC Class Codes: G06F 9/466 Transaction processing

Abstract

The present invention proposes a system for resending a process to a backup server farm from a client without waiting for the failure-detection, if no reply is received for a certain time. The transaction processing mechanism of the present invention has a transaction start processing mechanism in which an exclusive control using a valid processing authority token and data consistency are combined, and a commit processing mechanism in which determination on whether a commit is available or not based on a distributed agreement and replication of updated data. With the mechanisms, a system for shortening a service halt time when a failure occurs to a time as such it appears to a client that the service does not stop is provided.

Claims

1. ) A transaction processing method in a computer system comprising a plurality of clients and a plurality of server farms connected to a network, wherein each of said server farms comprises at least a database, a DB server for managing the database, and one or more application servers for communicating with said DB server and said clients, the transaction processing method comprises the steps of:

determining whether a transaction with the same ID is being executed or completes a commit by referencing a transaction ID according to a transaction start request from said client via said application server, and if said transaction with the same ID is being executed or completes a commit, returning rollback to the transaction start request;

checking whether a self server farm keeps a valid processing authority token or not, and if it does not keep said processing authority token, issuing an acquisition request of said valid processing authority token to all the other server farms, other than said self server farm, and waiting for completion of the acquisition request from a majority of said other server farms; and

said self server farm performing data consistency among all of said other server farms when said valid processing authority token is acquired.

2. ) The transaction processing method according to the claim 1, further comprising:

transferring said transaction ID of an objective transaction, data updated by the transaction and a processing result to be returned that requests the transaction to all of said server farms, and checking whether said data is copied to said database in at least a majority of server farms or not;

if said checking of said data being copied is succeeded, sending a message of a commit request to all of said other server farms, and if a commit agreement from a majority of said other server farms is received, determining that said commit request succeeded; and

sending a result of a commit established by said determining to all of said other server farms.

3. ) The transaction processing method according to the claim 2, further comprising:

if said commit request is received during said valid processing authority token acquisition is being processed, not replying to the commit request until said valid processing authority token acquisition process completed, or performing a resending request of a message of said commit request.

4. ) The transaction processing method according to the claim 2, further comprising:

sending a message of said commit request to all of said other server farms, and if an acquisition message of said valid processing authority token is received from when a reply for the commit request is received until a commit is established, not replying to the acquisition message of said valid processing authority token until the commit is established, or performing a resending request of an acquisition message of said valid processing authority token.

5. ) The transaction processing method according to the claim 1, further comprising:

receiving unestablished transaction logs from said other server farms and bringing a state of said unestablished transaction logs synchronized before said valid processing authority token acquisition completes.

6. ) The transaction processing method according to the claim 2, further comprising:

if transaction information with an unknown commit is included in said message when the acquisition request message of said valid processing authority token is received and when the acquisition request responding message of the valid processing authority token is received, referencing said transaction information, and if a commit or rollback of the transaction has been established, returning the result.

7. ) The transaction processing method according to the claim 2, further comprising:

determining whether those second other server farms, other than that sent a message of the commit request, keep said valid processing authority token or not to said commit request message, and if said second other server farms keep said valid processing authority token, returning a rejection to the commit request, and if they do not keep said valid processing authority token, returning approval.

8. ) The transaction processing method according to the claim 1, further comprising:

causing said client to set a transaction resending time which sends said transaction start request and a valid period of said valid processing authority token.

9. ) The transaction processing method according to the claim 1, wherein said valid processing authority token is a time-limited token including an expiration time.

10. ) A transaction processing system comprising a plurality of clients and a plurality of server farms connected to a network, wherein said server farm comprises at least a database, a DB server for managing the database, and one or more application servers for communicating with said DB server, the transaction processing system comprises:

a transaction redundancy determining unit for determining whether a transaction with the same ID is being executed or completes a commit by referencing a transaction ID according to a transaction start request from said client via said application server, and if the transaction with said same ID is being executed or completes a commit, returning rollback to the transaction start request;

a token exclusive control unit for checking whether the self server farm keeps a valid processing authority token or not, and if it does not keep said processing authority token, issuing an acquisition request of said processing authority token to all the server farms other than said self server farm, and waiting for completion of the acquisition request from a majority of server farms; and

a data consistency processing unit for said self server farm to perform data consistency among all of said server farms when said processing authority token is acquired, and

wherein said transaction processing system in a commit process of said transaction further comprises;

a data replication processing unit for transferring said transaction ID of an objective transaction, data updated by the transaction and a processing result to be returned to that requests the transaction to all of said other server farms, and checking whether said data is copied to said database in at least a majority of server farms or not;

a commit establishing processing unit for, if checking succeeded by said data replication processing unit, sending a message of a commit request to all of said other server farms, and if a commit agreement from a majority of server farms is received, determining that said commit request succeeded; and

a commit sending unit for sending a result of a commit established by said commit establishing processing unit to all of said other server farms.

11. ) The transaction processing system according to the claim 10, further comprising:

a valid period setting mechanism for causing the client to set a transaction resending time of the client which sends said transaction start request and a valid period of said processing authority token.

12. ) A transaction processing device in a computer system comprising a plurality of clients and a plurality of server farms connected to a network, wherein said server farm comprises at least a database, a DB server for managing the database and one or more application servers, the transaction processing device included in said DB server comprising:

a token request sending unit for sending processing authority token acquisition request message for the self server farm to acquire a right to access said database according to a transaction start request from said client via said application server;

a token reply receiving unit for receiving a reply message to said valid processing authority token acquisition request message;

a commit request sending unit for sending a commit request message; and

a commit reply receiving unit for receiving a reply message to said commit request message;

wherein said token request sending unit

sends a valid processing authority token acquisition request message to all the server farms other than said self server farm, if said self server farm does not keep the valid processing authority token and

said token reply receiving unit determines whether the valid processing authority token acquisition success or acquisition failure according to receiving a reply from a majority of server farms to said valid processing authority token acquisition request message,

said commit request sending unit sends a commit request message including a transaction log to all of said other server farms, if said valid processing authority token acquisition succeeded and,

said commit reply receiving unit determines that a commit succeeded, if an approval message is received from a majority of sever farms.

13. ) The transaction processing device according to the claim 12, wherein said valid processing authority token is a time-limited token including an expiration time.

14. ) The transaction processing device according to the claim 12, further comprising:

a valid period setting mechanism for causing said client to set a transaction resending time of a client which sends said transaction start request and a valid period of said valid processing authority token.

15. ) A computer program in a computer system comprising a plurality of clients and a plurality of server farms connected to a network, wherein said server farm comprises at least a database, a DB server for managing the database, and one or more application servers for communicating with said DB server and said clients, the computer program causes a computer system to execute:

determining whether a transaction with the same ID is being executed or completes a commit by referencing a transaction ID according to a transaction start request from said client via said application server, and if the transaction with said same ID is being executed or completes a commit, returning rollback to the transaction start request;

checking whether the self server farm keeps a valid processing authority token or not, and if it does not keep said valid processing authority token, issuing an acquisition request of said valid processing authority token to all the server farms other than said self server farm, and waiting for completion of the acquisition request from a majority of server farms; and

said self server farm performing data consistency among all of said server farms when said valid processing authority token is acquired.

16. ) The computer program according to the claim 15, further causing a computer system to execute:

transferring said transaction ID of an objective transaction, data updated by the transaction and a processing result to be returned to that requests the transaction to all of said server farms, and checking whether said data is copied to said database in at least a majority of server farms or not;

if checking succeeded in said checking, sending a message of a commit request to all of said other server farms, and if a commit agreement from a majority of server farms is received, determining that said commit request succeeded; and

sending a result of a commit established by said determining to all of said other server farms.

17. ) The computer program according to the claim 16, further causing a computer system to execute:

causing said client to set a transaction resending time of a client which sends said transaction start request and a valid period of said valid processing authority token.

18. ) The computer program according to the claim 17, wherein said valid processing authority token is a time-limited token including an expiration time.