ASYNCHRONOUS INTERCONNECT PROTOCOL FOR A CLUSTERED DBMS

• US 20070260714A1
• Filed: 03/30/2006
• Published: 11/08/2007
• Est. Priority Date: 03/30/2006
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines SA (International Business Machines Corporation)
• Inventors: Kalmuk, David, Ng, Jack, Lam, Cheuk, Pereyra, Hebert
• Granted Patent: US 7,801,997 B2
• Time in Patent Office: Days
• US Class Current: 709/223
• CPC Class Codes: G06F 16/24554 Unary operations; Data partitioning operations
• CPC Class Codes: G06F 16/273 Asynchronous replication or reconciliation

Abstract

A method, system and computer program product for an asynchronous interconnection between nodes of a clustered database management system (DBMS). Node timestamps are provided when each of the nodes in the cluster are started. Two or more communication conduits are established between the nodes. Each communication conduit between a local node and a remote node has an associated session identifier. The session identifiers and the timestamp from the remote node are associated to each communication conduit and the associated local node in the cluster. A timestamp is received from the remote node at the local node when establishing communication to determine if the remote node corresponds to the remote node incarnation identified by the timestamp and if DBMS communication between nodes can be initiated.

Claims

1. For a clustered database management system (DBMS) operatively coupled to a data processing system having memory for storing a database, a method for asynchronous interconnection between a first and a second node of the clustered database management system, the method comprising the steps of:

a) associating a first node timestamp for the first node and a second node timestamp for the second node when the nodes are started;

b) establishing a connection between the first node and second node by two or more communication conduits each having an associated session identifier;

c) associating, for the first node, the session identifiers with the second node timestamp;

d) receiving, at the first node, a timestamp from second node;

e) comparing the received second node timestamp to the second node timestamp associated with session identifiers; and

f) initiating communications between the first and second nodes via the communication conduits.

2. The method of claim 1, wherein step f) further comprises commencing communication between the first node and second node when the received second node timestamp matches the second node timestamp associated with one of the session identifiers.

3. The method of claim 1, wherein step b) further comprises associating a status to the communication conduits with the session identifiers, wherein the status is defined as either up or down for each respective node.

4. The method of claim 3, wherein step b) further comprises associating a communications socket identifier with one of the session identifiers when one of the communications conduits is established.

5. The method of claim 4, further comprising:

storing in a node manager object, for each node, the respective node timestamps and session identifiers, received timestamps and status identifier for each of the communication conduits; and

storing in a link table object, for each node, session identifiers, socket identifiers and status identifier for each of the communication conduits.

6. The method of claim 5, wherein step b) further comprises setting the status identifier to up in the node manager object and link table object when communication is established.

7. The method of claim 6, further comprising setting the status identifier associated with the communications conduit to down in the link table object when a drop or reset event is detected.

8. The method of claim 7, further comprising prior to step f) the steps of:

determining if the status identifier associated with the one of the session identifiers in the node manager object for the second node is equal to up;

determining if the one of the session identifiers in the node manager object and link table object match; and

establishing a communication socket to initiate a connect call to the second node on the associated communication conduit when the status identifier is equal to up and the session identifiers match.

9. The method of claim 8, further comprising storing a socket identifier for the established communication socket in the link table object.

10. The method of claim 5, further comprising subsequent to step f) the steps of:

determining that the second node has failed;

setting the status identifiers in the node manager object to down when communication between the first node and second node is not established;

closing the communication conduits to the second node; and

incrementing the session identifiers.

11. For a clustered database management system (DBMS) operatively coupled to a data processing system, a computer program product comprising a computer readable medium containing computer executable code for asynchronous interconnection between a first and a second node of the clustered database management system, the computer programmed product comprising:

code for associating a first node timestamp for the first node and a second node timestamp for the second node when the nodes are started;

code for establishing a connection between the first node and second node by two or more communication conduits each having an associated session identifier;

code for associating, for the first node, the session identifiers with the second node timestamp;

code for receiving, at the first node, a timestamp from second node;

code for comparing the received second node timestamp to the second node timestamp associated with session identifiers; and

code for initiating communications between the first and second nodes via the communication conduits.

12. The computer programmed product of claim 11, wherein the code for initiating communications between the first and second nodes further comprises code for commencing communication between the first node and second node when the received second node timestamp matches the second node timestamp associated with one of the session identifiers.

13. The computer programmed product of claim 11, wherein the code for establishing a connection between the first node and second node further comprises code for associating a communications socket identifier with one of the session identifiers when one of the communications conduits is established.

14. The computer programmed product of claim 13, further comprising:

code for storing in a node manager object, for each node, the respective node timestamps and session identifiers, received timestamps and status identifier for each of the communication conduits; and

code for storing in a link table object, for each node, session identifiers, socket identifiers and status identifier for each of the communication conduits.

15. The computer programmed product of claim 14, further comprising:

code for determining if the status identifier associated with the one of the session identifiers in the node manager object for the second node is equal to up;

code for determining if the one of the session identifiers in the node manager object and link table object match; and

code for establishing a communication socket to initiate a connect call to the second node on the associated communication conduit when the status identifier is equal to up and the session identifiers match.

16. The computer programmed product of claim 14, further comprising:

code for determining that the second node has failed;

code for setting the status identifiers in the node manager object to down when communication between the first node and second node is not established;

code for closing the communication conduits to the second node; and

code for incrementing the session identifiers.

17. For a clustered database management system (DBMS) operatively coupled to a data processing system, a system for asynchronous interconnection between a first and a second node of the clustered database management system, the system comprising:

a module for associating a first node timestamp for the first node and a second node timestamp for the second node when the nodes are started;

a module for establishing a connection between the first node and second node by two or more communication conduits each having an associated session identifier;

a module for associating, for the first node, the session identifiers with the second node timestamp;

a module for receiving, at the first node, a timestamp from second node;

a module for comparing the received second node timestamp to the second node timestamp associated with session identifiers; and

a module for initiating communications between the first and second nodes via the communication conduits.

18. The system of claim 17, wherein the module for initiating communications between the first and second nodes further comprises communication between the first node and second node when the received second node timestamp matches the second node timestamp associated with one of the session identifiers.

19. The system of claim 18, wherein the module for establishing a connection between the first node and second node further comprises associating a communications socket identifier with one of the session identifiers when one of the communications conduits is established.

20. The system of claim 19, further comprising:

a module for storing in a node manager object, for each node, the respective node timestamps and session identifiers, received timestamps and status identifier for each of the communication conduits; and

a module for storing in a link table object, for each node, session identifiers, socket identifiers and status identifier for each of the communication conduits.

21. The system of claim 20, further comprising a module for:

determining if the status identifier associated with the one of the session identifiers in the node manager object for the second node is equal to up;

determining if the one of the session identifiers in the node manager object and link table object match; and

establishing a communication socket to initiate a connect call to the second node on one of the communication conduits when the status identifier is equal to up and the session identifiers match.

22. The system of claim 21, further comprising a module for:

determining that the second node has failed;

setting the status identifiers in the node manager object to down when communication between the first node and second node is not established;

closing the communication conduits to the second node; and

incrementing the session identifiers.