Database cluster systems and methods for maintaining client connections

• US 20060242297A1
• Filed: 06/20/2006
• Published: 10/26/2006
• Est. Priority Date: 02/06/2001
• Status: Active Grant

• Current Assignee: Quest Software, Inc.
• Original Assignee: Quest Software, Inc.
• Inventors: Kalderon, Eyal, Romine, Bill, Aronoff, Eyal
• Granted Patent: US 7,512,682 B2
• Time in Patent Office: Days
• US Class Current: 709/225
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/10015 Access to distributed or replicated servers, e.g. using brokers
• CPC Class Codes: H04L 67/1029 using data related to the state of servers by a load balancer
• CPC Class Codes: H04L 67/1034 Reaction to server failures by a load balancer
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99955 Archiving or backup

Abstract

Aspects of embodiments of the present disclosure include a highly available database cluster that can maintain a connection with potentially geographically remote client application programs, including non-fault tolerant application programs, even in the event of one of the database management systems (DBMS) of the cluster becoming unavailable. For example, the database cluster can advantageously move a client connection between a failing, unbalanced, or overloaded DBMS, to another DBMS within the cluster. The database cluster can include connection managers that monitor a connection between a client application program and a primary DBMS. When one connection manager determines that the primary DBMS is unavailable, the connection manager of a secondary DBMS can assume the connection to the client application as if it were the primary DBMS. The connection manager can finish all open transactions, thereby avoiding the need to roll back the same. Moreover, the connection managers can monitor the connection at the DBMS communication level, such as, for example, the SQL*Net level.

Claims

1. A database cluster comprising:

a first computing system, the first computing system further comprising;

a primary connection manager that forms a Transmission Control Protocol/Internet Protocol (TCP/IP) connection with and receives transactions from at least one client, and

a primary database management system (DBMS) that executes the transactions on data stored in one or more data files; and

a second computing system, the second computing system further comprising;

a secondary connection manager, and

a secondary DBMS that communicates with the secondary connection manager and that can access data stored in the one or more data files,

wherein when an unbalanced workload exists between the first and second computing systems, the secondary connection manager transparently assumes the TCP/IP connection with the at least one client.

2. The database cluster of claim 1, wherein the secondary connection manager is configured to monitor the performance of the first computing system to determine when the unbalanced workload exists between the first and second computing systems.

3. The database cluster of claim 2, wherein the primary connection manager is configured to monitor the performance of the second computing system.

4. The database cluster of claim 1, wherein, upon transparently assuming the TCP/IP connection with the at least one client, the secondary connection manager is configured to replay incomplete portions of open transactions on the data through the secondary DBMS and to begin receiving additional transactions from the at least one client.

5. The database cluster of claim 1, wherein the primary connection manager and the secondary connection manager communicate with one another.

6. The database cluster of claim 5, wherein the primary connection manager and the secondary connection manager exchange statistics in order to monitor the TCP/IP connection.

7. The database cluster of claim 6, wherein the statistics include the number of clients connected to the primary connection manager.

8. The database cluster of claim 1, wherein the secondary connection manager further comprises a queue that stores copies of the transactions sent to the primary connection manager by the at least one client.

9. The database cluster of claim 8, wherein the secondary connection manager further comprises an import process that deletes from the queue data packets associated with transactions that have been committed by the primary DBMS.

10. A method of providing a fail-over database cluster, the method comprising:

forming a Transmission Control Protocol/Internet Protocol (TCP/IP) connection between a first computing system and at least one client;

receiving transactions from the at least one client with a primary connection manager of the first computing system;

executing the transactions with a primary database management system (DBMS) of the first computing system on data stored in one or more data files;

monitoring a balance of a workload between the first computing system and a second computing system; and

transparently assuming the TCP/IP connection with the second computing system when an unbalanced workload exists between the first and second computing systems.

11. The method of claim 10, additionally comprising, after said transparently assuming the TCP/IP connection:

replaying through a secondary DBMS of the second computing system incomplete portions of open transactions;

receiving with a secondary connection manager of the second computing system additional transactions from the at least one client; and

executing the additional transactions against the one or more data files.

12. The method of claim 11, additionally comprising sending with the secondary connection manager at least one keepalive message to the at least one client.

13. The method of claim 10, wherein said monitoring comprises exchanging statistics between the first computing system and the second computing system.

14. The method of claim 13, wherein the statistics comprise the number of clients connected to the first computing system.

15. The method of claim 10, additionally comprising deleting from a queue of the second computing system data packets associated with transactions committed by the primary DBMS.

16. A database cluster for providing for client connection fail-over, the database cluster comprising:

first means for forming a Transmission Control Protocol/Internet Protocol (TCP/IP) connection with a client computer, wherein said first means is further configured to receive transactions from the client computer;

second means for receiving the transactions from said first means and for executing the transactions on data stored in at least one data file;

third means for monitoring the TCP/IP connection between said first means and the client computer and for transparently assuming the TCP/IP connection with the client computer while keeping the client TCP/IP connection alive from a perspective of the client; and

fourth means for accessing the data stored in the at least one data file, said fourth means being in communication with said third means.

17. The database cluster of claim 16, wherein said third means is configured to transparently assume the TCP/IP connection with the client computer when said third means detects a failure of the TCP/IP connection between said first means and the client computer.

18. The database cluster of claim 16, wherein said third means is configured to transparently assume the TCP/IP connection with the client computer when said third means detects a failure of said second means.

19. The database cluster of claim 16, wherein said third means is configured to transparently assume the TCP/IP connection with the client computer when said third means detects an unbalanced workload between said second means and said fourth means.

20. The database cluster of claim 16, wherein said third means further comprises means for storing copies of transactions received from the client computer by said first means.