MOST ELIGIBLE SERVER IN A COMMON WORK QUEUE ENVIRONMENT

• US 20080307111A1
• Filed: 08/18/2008
• Published: 12/11/2008
• Est. Priority Date: 03/29/2002
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Wilcock, Glenn Randle
• Granted Patent: US 8,190,743 B2
• Time in Patent Office: Days
• US Class Current: 709/242
• 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 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/1029 using data related to the state of servers by a load balancer
• CPC Class Codes: H04L 67/1038 Load balancing arrangements to avoid a single path through a load balancer
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A system and method for managing servers. The system comprises a plurality of servers for processing messages, at least one client for transmitting messages to and receiving messages from the servers, and processor means for maintaining a list indicating whether at least one of the servers is eligible to process messages. Preferably, the servers are adapted to process messages of different types; and the processor means includes means to indicate on said list whether, for each of the different types of messages, at least one of the servers is eligible to process each of the different types of messages. Also, in the preferred embodiment, each of the clients includes means to read the list, before the client transmits a message of a given type to one of the servers, to determine whether at least one of the servers is eligible to process messages of the given type. In addition, the processor means may notify the clients when changes are made to the list, and each of the clients may include means for removing messages from the servers in case there is no longer a server eligible to process the messages.

Claims

1. A server management system comprising:

a shared queue;

a plurality of servers each operable to determine whether it has capacity to process a message, and if determined to have the capacity, further operable to dequeue a message in the shared queue, process the message and place one or more responses in the shared queue;

at least one client for transmitting messages to the shared queue and receiving messages in the shared queue from the plurality of servers;

a list having a most eligible server status record accessible by said client, the most eligible server status record being updated when one or more of the plurality of servers connects to the shared queue and determines that its eligibility to process requests is greater than is currently reflected in the most eligible server status record, the most eligible server status record further being updated when one or more of the plurality of servers disconnects from the shared queue; and

processor means for maintaining the list further indicating whether at least one of the plurality of servers is eligible and available to process a particular message from the at least one client, the list further indicating one or more types of messages eligible to be processed by said at least one of the plurality of servers, said at least one client reading the list before placing said particular message to the shared queue to determine if a server is available to process said particular message, said at least one client enqueuing said particular message in the shared queue only if it is determined that a server is available,

wherein if there is a change in the most eligible server status record, the client is notified of the change, and if the most eligible server status record is lower than its previous status, the client is provided with an option of removing one or more requests from the shared queue for which there is no longer a server eligible to process.

2. A server management system according to claim 1, wherein:

the processor means is further operable to maintain changes in the list.

3. A server management system according to claim 1, wherein the at least one client includes means to read said list, before the at least one client transmits a message of a given type to one of the plurality of servers, to determine whether at least one of the plurality of servers is eligible to process messages of a given type.

4. A server management system according to claim 1, wherein the processor means notifies the at least one client when changes are made to said list.

5. A server management system according to claim 1, wherein the at least one client includes means for removing messages from the plurality of servers in case there is no longer a server eligible to process the messages.

6. A program storage device readable by machine, tangibly embodying a program of instructions executable by the machine to perform method steps for managing a plurality of servers, said method steps comprising:

providing a shared queue;

providing a plurality of servers each operable to determine whether it has capacity to process a message, and if determined to have the capacity, further operable to dequeue a message in the shared queue, process the message and place one or more response messages in the shared queue;

using at least one client to transmit messages to the shared queue and to receive messages in the shared queue from the plurality of servers;

establishing a list having a most eligible server status record accessible by said client, the most eligible server status record being updated when one or more of the plurality of servers connects to the shared queue and determines that its eligibility to process requests is greater than is currently reflected in the most eligible server status record, the most eligible server status record further being updated when one or more of the plurality of servers disconnects from the shared queue; and

providing a processor for maintaining the list further indicating whether at least one of the plurality of servers is eligible and available to process a particular message from the at least one client, the list further indicating one or more types of messages eligible to be processed by said at least one of the plurality of servers, said at least one client checking the list before transmitting said particular message to the shared queue to determine if a server is available to process said particular message, said at least one client enqueuing said particular message in the shared queue only if it is determined that a server is available,

if there is a change in the most eligible server status record, notifying the client of the change, and if the most eligible server status record is lower than its previous status, providing the client an option of removing one or more requests from the shared queue for which there is no longer a server eligible to process.

7. A program storage device according to claim 6, wherein:

the processor is further operable to maintain changes in the list.

8. A program storage device according to claim 6, wherein said method comprises the further step of, the at least one client reading said list, before the at least one client transmits a message of a given type to one of the plurality of servers, to determine whether at least one of the plurality of servers is eligible to process messages of the given type.

9. A program storage device according to claim 6, wherein said method comprises the further step of using the processor to notify the at least one client when changes are made to said list.

10. A program storage device according to claim 6, wherein said method comprises the further step of, the at least one client removing messages from the plurality of servers in case there is no longer a server eligible to process the messages.

11. A data processing system comprising:

a common queue;

a plurality of servers for processing messages of different types, each operable to determine whether it has capacity to process a message, and if determined to have the capacity, further operable to dequeue a message in the common queue, process the message and place one or more response messages in the common queue;

at least one client for transmitting messages to the common queue and receiving messages in the common queue from the plurality of servers;

a list having a most eligible server status record accessible by said client the most eligible server status record being updated when one or more of the plurality of servers connects to the shared queue and determines that its eligibility to process requests is greater than is currently reflected in the most eligible server status record, the most eligible server status record further being updated when one or more of the plurality of servers disconnects from the shared queue; and

processor means for maintaining the list further indicating whether, for each of the different types of messages, at least one of the plurality of servers is eligible and available to process said each of the different types of messages, the list further indicating one or more types of messages eligible to be processed by said at least one of the plurality of servers, said at least one client checking the list before transmitting a particular message to the common queue to determine if a server is available to process said particular message, said at least one client enqueuing said particular message in the common queue only if it is determined that a server is available,

wherein if there is a change in the most eligible server status record, the client is notified of the change, and if the most eligible server status record is lower than its previous status, the client is provided with an option of removing one or more requests from the shared queue for which there is no longer a server eligible to process.

12. A data processing system according to claim 11, wherein the processor means is further operable to maintain changes in the list.

13. A data processing system according to claim 11, wherein the at least one client includes means for removing messages from the plurality of servers in case there is no longer a server eligible to process the messages.