Recoverable asynchronous message driven processing in a multi-node system

• US 20050038835A1
• Filed: 08/12/2004
• Published: 02/17/2005
• Est. Priority Date: 08/14/2003
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Chatterjee, Debashish, Chidambaran, Lakshminarayanan
• Granted Patent: US 8,365,193 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/203 using migration
• CPC Class Codes: G06F 11/2038 with a single idle spare processing component
• CPC Class Codes: G06F 11/2041 with more than one idle spare processing component
• CPC Class Codes: G06F 11/2043 where the redundant components share a common memory address space
• CPC Class Codes: G06F 2209/505 Clust
• CPC Class Codes: G06F 9/466 Transaction processing
• CPC Class Codes: G06F 9/485 Task life-cycle, e.g. stopping, restarting, resuming execution G06F9/4881 takes precedence

Abstract

An approach provides for recovery of message driven directors responsible for dynamically allocating resources within a multi-node database system. The receipt of a message, the action taken in response to it, and other messages sent in furtherance of the action, are performed within a single transaction. In this way, the messages and other data are left in a state consistent with the message and action taken in response being fully processed or not processed at all. A standby director, stepping in for a crashed director, inherits a state consistent with where a crashed director last successfully completed an action. The approach insulates directors from the special perils of performing high latency actions by delegating the performance of such actions to a job, (i.e. another process).

Claims

1. A computer-implemented method for performing actions in response to messages transmitted within a computer system, the method comprising the steps of:

receiving within a queue a first message that notifies of a condition;

as a first transaction initiated by a first entity, performing first operations that include;

dequeueing the first message from the queue, and

performing a first operation related to the condition;

wherein said first transaction terminates without being committed;

as a second transaction initiated by a second entity, performing second operations that include;

dequeueing the first message from the queue, and

performing a second operation related to the condition; and

committing said second transaction.

2. The method of claim 1, wherein:

the first message notifies of a violation of service-level agreements associated with the computer system; and

the first operation attempts to adjust allocation of resources within the computer system to remedy the violation.

3. The method of claim 2, wherein the first operations include requesting that a first message be transmitted.

4. The method of claim 2, wherein:

the first operations include requesting that a third message be transmitted to a third entity, said third message requesting an action related to the condition; and

the second operations include requesting a fourth message to be transmitted to a third entity, said fourth message requesting said action related to the condition.

5. The method of claim 2, wherein the first operations include causing a third message for a recipient to be added to the queue in a way that causes the third message to be received by the recipient after a specified period of time, wherein said third message notifies of said condition.

6. The method of claim 5, after said specified period of time:

as a third transaction, performing third operations that include;

dequeueing the third message from the queue, and

performing a third operation related to the condition.

7. The method of claim 5, the steps further including:

receiving within the queue a fourth message that notifies that said condition has abated;

supplying said fourth message to said first entity; and

wherein supplying said fourth message to said first entity causes dequeueing of said third message.

8. The method of claim 2, wherein:

said first entity includes a first process executing on a node of said computer system; and

the first operations include initiating an asynchronous process executing on said computer system to perform said first operation.

9. The method of claim 8, wherein the first operations include causing a third message for a recipient to be added to the queue in a way that causes the third message to be received by the recipient after a specified period of time, wherein said third message identifies said asynchronous process.

10. The method of claim 9, the steps further including:

receiving said third message;

determining that said third message identifies said asynchronous process; and

in response to determining that said third message identifies said asynchronous process, ceasing execution of said asynchronous process.

11. The method of claim 9, the steps further including:

receiving a fourth message that includes data that;

indicates a result of the first operation performed by said asynchronous process performing the action, and

identifies said asynchronous process; and

in response to receiving the fourth message, dequeueing the third message.

12. The method of claim 1, wherein:

the computer system includes a first node and a second node;

the first entity is hosted by said first node;

the second entity is hosted by said second node; and

the second entity serves as standby to perform a responsibility of said first entity in response to ceasing execution of said first entity.

13. The method of claim 12, the steps further including:

detecting expiration of a period time; and

in response to detecting the expiration of the period of time, ceasing execution of said first entity.