KR20120048460A - Log management method - Google Patents

Abstract

PURPOSE: A log management method is provided to reduce the number of data messages through a core network by localizing a messaging log. CONSTITUTION: A representative process receives a message from a transmission process(315). In case the representative process is not the final receiver of the message, the representative process transmits the message to a local member process(317,320). The representative process receives a reception serial number about the message from the local member process(325). The representative process records complete log information in a non-volatile memory.

Description

Log management method

The present invention relates to a message log management method that can quickly recover in the event of a failure at a low cost in a large and geographically dispersed system.

Distributing (ubiquitous) and low-cost, but high-performance, small and medium computing devices can be connected very easily to other computing devices over wired and wireless, causing significant architectural changes in distributed computing systems. This technical trend allows randomly connected computing device communities to provide a low cost, high performance computing environment for the general user. However, this technical diversity can create reliability problems that are difficult to solve for the current distributed systems mentioned above. Many rollback-recovery methods have been proposed to provide fault tolerance for long-running distributed applications on small cluster and grid computing platforms.

Of those methods, the sender-based message logging technique combined with checkpoint recording is one of the least expensive fault tolerance techniques that can be applied for this purpose. This technique can significantly reduce the high normal performance costs caused by receiver-based message logging techniques synchronously logging messages to secure storage. This advantage is obtained because each message sender's volatile memory is used as a storage for message logging. However, the sender-based message logging technique requires the additional communication costs required for the message sender to obtain the Receive Sequence Number (RSN) of the message from the message receiver and informs the receiver about it, and the complexity of the recovery process for each failed process. And high execution time.

The present invention is to provide a log management method that can localize the message logging and recovery process as much as possible.

Through this, the present invention is to provide a log management method that can significantly reduce the control and data messages through the core network during the message logging and recovery process.

As a result, the present invention can significantly shorten the completion time according to the recovery process in the event of any process failure.

According to an aspect of the present invention, a method of managing a log of a sender-based message in a system including a plurality of processes and a recording medium recording a program for performing the method are provided.

According to an embodiment of the present invention, there is provided a method of managing a log of a sender-based message in a system including a plurality of processes, the method comprising: a representative process receiving a message from a sending process; If the representative process is not the last recipient of the message, forwarding the message to a receiving process and receiving a serial number for the message from the receiving process; And writing, by the representative process, complete log information including the reception serial number to a volatile memory.

The sending process may write partial log information for the message in volatile memory of the sending process corresponding to sending the message.

The partial log information is at least one of a transmission serial number of the message, identification information of the transmission process, identification information of the reception process, and actual data of the message.

In response to recording the complete log information, the representative process sends a response according to the reception serial number reception to the reception process; And the receiving process may transmit the following message to another process according to the response.

The recovery process that recreates the failed process may include broadcasting a recovery request message to another process; When the recovery process receives a response including a message and log information to the recovery request message, storing complete log information of the response in a received serial number order in a replay buffer of the recovery process; The recovery process storing partial log information for a message to which the serial number is not assigned; And regenerating, in sequence, all messages sent before the failure in an order arranged in the replay buffer.

The step of broadcasting the recovery request message may include: if the failed process is a representative process, the recovery process broadcasts the recovery request message to another process in or out of a region; And if the failed process is not a representative process, the recovery process may include broadcasting the recovery request message to another process in the region.

If the final receiving process of the message included in the response to the recovery request message is not the representative process, then the recovery process sends the message to the final receiving process; And the recovery process may include receiving a reception serial number from the final reception process and performing a complete message logging procedure including the reception serial number.

The partial log information is stored and processed in a first-in, first-out order.

Replaying the messages in order may be performed after the recovery process has received a response to the recovery request message from all processes in the region.

According to another embodiment of the present invention, a program of instructions that can be executed by an electronic device to perform a method for managing a log of sender-based messages in a system including a plurality of processes is tangibly implemented. A recording medium having recorded thereon a program that can be read by an apparatus, the recording medium comprising: a representative process receiving a message from a transmission process; If the representative process is not the last recipient of the message, forwarding the message to a receiving process and receiving a serial number for the message from the receiving process; And a recording medium on which a program for performing the step in which the representative process writes the complete log information including the reception serial number in the volatile memory.

By providing a log management method according to an embodiment of the present invention, it is possible to localize the message logging and recovery process as much as possible.

Through this, the present invention can significantly reduce the control and data messages through the core network during the message logging and recovery process, and can significantly shorten the completion time according to the recovery process in case of any process failure.

1 is a flow chart illustrating a conventional inter-process message transfer process.
2 is a schematic diagram showing a conventional inter-process message transfer process.
3 is a flowchart illustrating a message log management process according to an embodiment of the present invention.
4 is a schematic diagram illustrating a sender-based message log management method according to an embodiment of the present invention.
5 is a diagram schematically illustrating a sender-based message logging process during normal operation according to an embodiment of the present invention.
6 is a flow chart illustrating the recovery process of any process failure in accordance with one embodiment of the present invention.
7 illustrates a formal representation of a recovery process in accordance with one embodiment of the present invention.
8 is a flowchart illustrating a recovery process according to a failure of a representative process according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

A system for managing a log of a sender-based message according to an embodiment of the present invention is composed of a set P of n (n is a natural number) sequential processes, and there may be a stable storage that each process can always access.

In addition, the computing devices constituting the system may be distributed in various regions, and the most resource-owning process or computing device in each region is elected as a representative. In this specification, elected representatives will be collectively described as a representative process to facilitate understanding and explanation. Here, the resource may be at least one of a CPU, a memory, a storage, and a network.

Hereinafter, in the present specification, a system for managing a log of a sender-based message will be described assuming three processes and seven processes are performed to facilitate understanding and explanation. Of course, in an implementation, the sender-based log management system may be configured with at least one region, and all of them may be equally applied when a plurality of processes are performed.

In addition, each process that fails in the sender-based message log storage method is rolled back to the state at the time of the last checkpoint storage, and has a characteristic of replaying messages received by the failed process after the checkpoint storage using recovery information stored in the representative process. Because of this feature, we can see that a consistent recovery in the event of a process failure does not require a log of messages delivered before the process saves the last checkpoint.

[Description of Fig. 1]

1 is a flowchart illustrating a conventional inter-process message transfer process. Hereinafter, for convenience of understanding and explanation, the subject that transmits a message will be referred to as a transmission process, and the subject that receives a message will be collectively described as a reception process.

In step 110 the transmission process stores partial message log information in the volatile memory of the transmission process corresponding to the message transmission to the reception process.

In the present specification, the partial message log information is not a complete log of the message, but refers to information in which some of the information set for log recording is recorded as a log.

Accordingly, when some information of the log information for a message is recorded, the log information is called partial message log information. When all information for the log is recorded (or updated) in the log information, the log information is converted into a complete message log. This will be referred to as information.

The partial message log information includes at least one of a transmission serial number, a reception process identification information, a transmission process identification information, and actual data.

Here, the transmission serial number indicates the serial number of the message sent by the transmission process, and the reception process identification information and the transmission process identification information indicate identification information for identifying the process, respectively.

The method of assigning a transmission serial number may be given such that the transmission serial number of the preceding message is larger than the transmission serial number of the following message, and the transmission serial number of the preceding message is smaller than the transmission serial number of the following message. May be Obviously, a small serial number may not necessarily indicate a preceding message.

In addition, it is obvious that the difference in transmission serial numbers between the preceding message and the following message may not necessarily be the same difference.

However, in the present specification, in order to facilitate understanding and explanation, when the transmission serial number is small, it is assumed that the preceding message is assumed to be described.

In step 115 the sending process receives a receiving serial number corresponding to the message sent from the receiving process.

Here, the reception serial number represents the serial number of the message received by the reception process. The receiving serial number may be given in the order in which the receiving process received the message. The reception serial number may also be assigned in the same manner as the transmission serial number assigning method. That is, like the transmission serial number, the reception serial number may not necessarily indicate a message previously received. However, for convenience of understanding and explanation, in the present specification, like the transmission serial number, when the reception serial number is small, it will be described on the assumption that it indicates a previously received message.

In step 120 the sending process performs a complete message logging procedure.

Here, the complete message logging process is a process of updating the message log information including the reception serial number.

In step 125 the sending process notifies the receiving process of the completion of the complete message logging procedure.

As described above, the conventional sender-based message log management method has a disadvantage in that a lot of communication between networks occurs when communication between processes in each region becomes frequent.

[Description of Fig. 2]

2 is a schematic diagram showing a conventional inter-process message transfer process. For convenience of understanding and explanation, it is assumed that it is distributed in three regions in a distributed system, and that there are seven processes in each region.

In addition, in FIG. 2, m1 to m4 represent messages transmitted from each transmission process to a reception process, and p1 to p7 represent processes driven in each region on a distributed system.

As shown in Fig. 2, each process writes complete message log information to the process that sent the message after the message transmission, at the time when the reception serial number is obtained from another process receiving the message.

Accordingly, as shown in FIG. 2, when interprocess communication in each region becomes frequent, there is a disadvantage in that a lot of communication occurs between networks.

For ease of understanding and explanation, we will describe how p7 sends a message to p5 and then writes complete message log information for that message.

At 210, p7 writes partial message log information to volatile memory at p7 as the message is sent to p5. As described above, the partial message log information may be at least one of a message transmission serial number, p7 identification information, and p5 identification information.

Then, at 215, p5 assigns a reception serial number according to the message reception, and transmits it to p7. Accordingly, p7 updates the reception serial number to partial message log information according to the reception serial number received from p5 to perform a complete message logging process.

At 220 p7 notifies p5 that the complete message logging process has been performed. Accordingly, p5 can send the message to another process. Hereinafter, since the method of transmitting m2, m3 and m4 and recording the message log according to the same in FIG. 2 is the same, overlapping description will be omitted.

In FIG. 2, when logging messages of m1, m2, and m4, it can be seen that communication between regions occurs frequently.

[Description of Fig. 3]

3 is a flowchart illustrating a message log management process according to an embodiment of the present invention. Hereinafter, a description will be given on the assumption that a distributed system according to an embodiment of the present invention includes a storage for message logging on a representative process in a region. As described above, the representative process may be selected as the process that occupies the most resources in the region.

In step 310, the sending process stores partial message log information, including the transmission serial number, sender process identification, and receiver process identification of the message to be sent, in the volatile memory of the sender process. Of course, in this specification, each message may include actual data of the message. Accordingly, it is obvious that the partial message log information and the complete message log information may each contain further actual data of the message.

In step 315, the sending process sends the message to a representative process in the region to which the receiver process belongs (to be referred to as a regional representative process for ease of understanding and explanation).

Naturally, step 315 may be performed before step 310.

In step 317, the representative process determines whether the representative process is the last recipient of the received message according to the reception of the message from the transmission process.

If the representative process is not the final recipient, then in step 320 the representative process sends a message received from the sender process to a member process in the region.

Subsequently, in step 325, the representative process receives the reception serial number for the message sent from the local member process, and stores complete message log information including the received reception serial number in the volatile memory of the representative process.

In operation 330, the representative process transmits a response according to the reception serial number reception to the member process in the region according to the storage of the message log information.

However, if the representative process is the final recipient, then in step 335 the representative process assigns a reception serial number to the received message and sends the assigned reception serial number to the sending process that sent the message.

In this way, by maintaining the complete message log information in the volatile memory of the representative process in the region, it can be seen that the number of inter-regional communications significantly reduced when managing the message log according to the inter-process message transfer.

In Figure 4 according to an embodiment of the present invention will be described in detail the process of transferring the inter-process message in the same order as in FIG.

[Description of Fig. 4]

4 is a schematic diagram illustrating a sender-based message log management method according to an embodiment of the present invention. In FIG. 4, p1 to p7 represent processes, and it is assumed that p3, p4, and p6 are representative processes of respective regions.

Referring to FIG. 4, it can be seen that communication between the outside of each region is significantly reduced compared to FIG. 2.

First, for convenience of understanding and explanation, a process of logging a message according to the first message transmission will be described.

P7 in the third region writes the partial message log information for the first message to the volatile memory of p7 as the first message is sent to the second region.

The representative process of the second region sends (415) the first message to the reception process p5 in the region if the last recipient of the first message is not the representative process upon receipt of the first message.

The second regional representative process then receives a serial number from a first message receiving process in the region. Accordingly, the second local representative process writes complete message log information, including the serial number of the first message, to the volatile memory of the representative process (420).

The second area representative process notifies the receiving process p5 in the area of completion of the complete message logging process (425). Accordingly, the reception process p5 may perform a second message transfer process.

Hereinafter, since the message logging process according to the delivery of the second message, the third message, and the fourth message of FIG. 4 between an internal process and / or an external process is the same as the message logging process according to the first message delivery, a redundant description will be omitted. Let's do it.

In this way, by maintaining the complete message log information according to the inter-process message delivery to the representative process in the region, there is an advantage that can significantly reduce the communication outside the region due to message delivery.

[Description of Fig. 5]

5 is a diagram schematically illustrating a sender-based message logging process during normal operation according to an embodiment of the present invention.

In FIG. 5, P _sndr represents a transmission process, and Msg-Send (m) is a procedure of transmitting a message and writing partial message log information of a message transmitted to the volatile memory of the P _sndr .

BR _Ai represents the Ai regional representative process, and Msg-Recv (m) of Broker BR _Ai forwards the message to the final receiving process in the region if the Ai regional representative process is not the final recipient of the message. If the message is the final recipient, the procedure assigns a receiving serial number and sends it to the sending process.

P _rcvr represents a final receiving process, and Msg-Recv (m) of Receiver P _rcvr is a _procedure in which the last receiving process allocates a receiving serial number according to the message reception and delivers the receiving serial number to a representative process in the region.

RSN-Rcvr (RSN of m) is a procedure for updating the log information in the volatile memory of the message transmission process or the representative process the reception serial number of the received message m.

RSN-Confirm (m) notifies the receiving process of message m to record the complete message log information for message m in the volatile memory of the sending process of message m so that after receiving message m, the receiving process is actually sending It is a procedure to make it possible.

[Description of Fig. 6]

6 is a flowchart illustrating a recovery process according to any process failure according to an embodiment of the present invention, and FIG. 7 is a view showing a formal representation according to a recovery process according to an embodiment of the present invention. In the following description, it is assumed that any one of the member processes in the region is not a representative process in any region.

The failed process in step 610 is regenerated on another available process. How the failed process is reproduced on other available processes is obvious to those skilled in the art, and thus a separate description thereof will be omitted. Hereinafter, the process of regenerating the failed process for the convenience of understanding and explanation will be referred to as a recovery process.

At step 615, the recovery process recovers to the pre-failure state from the most recent checkpoint of the failed process maintained in the secure store, and broadcasts a recovery request message to the local member process.

In step 620, the recovery process receives a response message including the message sent and the log information corresponding to the recovery request message from another process in the area.

In step 625, the recovery process stores the received messages in the replay buffer using the log information.

At this time, the recovery process stores the message in the replay buffer in a first-in first-out manner when a message is received that is not assigned a reception serial number.

In step 630 the recovery process replays the messages in the order arranged in the replay buffer.

FIG. 7 is a diagram schematically illustrating a sender-based message logging process when performing recovery. FIG. 7 illustrates an algorithm representing a recovery process when a member process in a region other than the representative process fails.

[Description of Fig. 8]

8 is a flowchart illustrating a recovery process according to a failure of a representative process according to an embodiment of the present invention. In the following description, it is assumed that a representative process is regenerated on another available process. In order to facilitate understanding and explanation, the regenerated representative process will be described collectively as a recovery process.

In step 810 the recovery process recovers to the pre-failure state from the most recent checkpoint.

In step 815 the recovery process broadcasts a recovery request message to another process before failure. At this point, the recovery process may broadcast a recovery request message to other processes in and out of the region.

In step 820, the recovery process receives from the other process a reply message including the message sent and the log information corresponding to the recovery request message.

In step 825 the recovery process determines whether the final recipient of the reply message is the recovery process.

If the last recipient of the reply message is the recovery process, then at step 830 the recovery process stores the received messages in the reception serial number in the replay buffer using the log information. Of course, the recovery process stores the message in the replay buffer on a first-in, first-out basis when a message is received that is not assigned a serial number.

The recovery process then replays the messages in the order arranged in the replay buffer.

However, if the last recipient of the reply message is not the recovery process, then at step 840 the recovery process sends the message to the final receiving process.

In step 845, the recovery process receives the reception serial number from the last reception process and performs a complete message log information recovery process including the received reception serial number.

Meanwhile, the method for performing the sender-based message logging procedure according to the embodiment of the present invention may be implemented in the form of program instructions that can be executed through various electronic means for processing information and recorded in the storage medium. The storage medium may include program instructions, data files, data structures, etc. alone or in combination.

Program instructions to be recorded on the storage medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of software. Examples of storage media include magnetic media such as hard disks, floppy disks and magnetic tape, optical media such as CD-ROMs, DVDs, and magnetic-optical media such as floppy disks. hardware devices specifically configured to store and execute program instructions such as magneto-optical media and ROM, RAM, flash memory, and the like. In addition, the above-described medium may be a transmission medium such as an optical or metal wire, a waveguide, or the like including a carrier wave for transmitting a signal specifying a program command, a data structure, and the like. Examples of program instructions include not only machine code generated by a compiler, but also devices that process information electronically using an interpreter, for example, high-level language code that can be executed by a computer.

The hardware device described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It will be understood that the invention may be varied and varied without departing from the scope of the invention.

Claims (10)

A method of managing a log of sender-based messages in a system comprising a plurality of processes, the method comprising:
The representative process receiving the message from the sending process;
If the representative process is not the last recipient of the message, forwarding the message to a receiving process and receiving a serial number for the message from the receiving process; And
And the representative process writes complete log information including the received serial number to volatile memory.
The method according to claim 1,
And wherein said sending process writes partial log information for said message in volatile memory of said sending process corresponding to sending said message.
The method of claim 2,
And the partial log information is at least one of a transmission serial number of the message, identification information of the transmission process, and identification information of the reception process.
The method according to claim 1,
In response to recording the complete log information, the representative process sends a response according to the reception serial number reception to the reception process; And
The receiving process includes the step of sending a subsequent message to another process according to the response.
The method according to claim 1,
The recovery process that recreates the failed process may include broadcasting a recovery request message to another process;
When the recovery process receives a response including a message and log information to the recovery request message, storing complete log information of the response in a received serial number order in a replay buffer of the recovery process;
The recovery process storing partial log information for a message to which the serial number is not assigned; And
And the recovery process replays in sequence all the messages sent before the failure in the order arranged in the replay buffer.
The method of claim 5,
Broadcasting the recovery request message,
If the failed process is a representative process, the recovery process broadcasts the recovery request message to another process in or out of the region; And
If the failed process is not a representative process, the recovery process comprises broadcasting the recovery request message to another process in the region.
The method of claim 5,
If the final receiving process of the message included in the response to the recovery request message is not the representative process, then the recovery process sends the message to the final receiving process; And
The recovery process includes receiving a reception serial number from the last reception process, and performing a log recovery procedure including the reception serial number.
The method of claim 5,
The partial log information is stored and processed in a first-in, first-out order.
The method of claim 5,
Reproducing the messages in order,
And the recovery process is performed after receiving a response to the recovery request message from all processes in the region.
In order to perform a method for managing a log of sender-based messages in a system including a plurality of processes, a program of instructions that can be executed by an electronic device is tangibly implemented, and a program that can be read by the electronic device is implemented. In the recording medium
The representative process receiving the message from the sending process;
If the representative process is not the last recipient of the message, forwarding the message to a receiving process and receiving a serial number for the message from the receiving process; And
And recording the program by the representative process to write the complete log information including the received serial number into the volatile memory.

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