JP2007334575A - Message communication method, system, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology which can process a request message including retransmission without incurring mutual resource congestion among receiving side information processing systems to which retransmission requests are sent by applying a load distribution device for load distribution of high reliability messaging method. <P>SOLUTION: A field for a retransmission request flag is set in identification information of the request message, and then the request message whose retransmission flag is set ON is transmitted by a communication device when retransmitting a message. The identification information of the request message in the message receiving status tables of the receiving information processing systems is stored in a storage when retransmission information which does not mean retransmission is set in the identification information of the received request message. The effectiveness of the request message is judged depending on how the identification information of the request message has been already stored in the message receiving status tables by referring to the message receiving status tables of all the receiving information processing systems in the storage when the retransmission information which means retransmission is set in the identification information of the received request message. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a message communication technique for realizing load distribution in message communication.

  In general, in order to realize a certain business system, it is necessary for a plurality of businesses arranged on the network to cooperate with each other, and messages are transmitted and received between the businesses. Here, a program that transmits a request message and requests processing is called a client program, and a program that receives a request message and executes business processing is called a server program. A program that is located between the client program and the server program and implements message communication via a network is called a communication program.

  There are two types of message transmission / reception modes: synchronous communication and asynchronous communication. Synchronous communication is a method for transmitting and receiving messages while a client program and a server program are operating simultaneously, and the client program and the server program operate synchronously. That is, the client program ends the process when the message arrives at the server program and the response message is received from the server program. Here, it is a communication program that actually transmits and receives messages via the network. On the other hand, asynchronous communication is a method in which a client program and a server program transmit and receive messages without being aware of each other's operating state, and the client program and server program operate asynchronously. That is, the communication program mediates message delivery, and the client program ends the process at the stage of designating the receiving side and requesting the communication program to send a message. The server program receives a message from the communication program at an arbitrary timing. The message transmission through the network at this time is completed when the transmission side communication program transmits a message to the reception side communication program and receives a response message from the reception side communication program.

  These message communications may fail due to various failures such as network failures and server program down. If the message communication fails, there is a possibility that a message is lost or a message is transmitted twice in both the synchronous communication mode and the asynchronous communication mode.

  In recent years, with the widespread use of the Internet, services that require “guaranteed one-time message transmission” such as deposit and withdrawal processing to bank accounts have begun to be used. For this reason, high reliability is required for message communication, and standardization of message communication rules is underway.

  As an example of such standardization, there is a messaging standard WS-Reliability for realizing high reliability of SOAP (Simple Object Access Protocol) communication of a Web service standardized by a standardization organization OASIS (Organization for the Advancement of Structured Information Standards). In order to “guarante one-time message transmission reliably”, methods of (i) delivery guarantee and (ii) prevention of duplication are defined. The communication program on the transmission side guarantees (i) by retransmitting the message until an acknowledgment is received from the communication program on the reception side. The communication program on the receiving side determines the identifier given to the message. If the identifier has not been received before, the received message is passed to the server program and an acknowledgment is sent to the communication program on the transmitting side. In the case of (ii), (ii) is guaranteed by sending a confirmation response to the communication program on the sending side after discarding the received message. The messaging system that achieves this high reliability will be referred to as high reliability messaging. Patent Document 1 also describes a reliable messaging system.

  By the way, in a system in which a large number of processing requests are generated from a large number of client programs, a load distribution device is installed between a device that operates the client program and a device that operates the server program, and a processing device that operates the server program is installed. Generally, a configuration is adopted in which the load of processing requests is distributed to a plurality of devices by arranging a plurality of devices. The load balancer terminates the connection from the device running the client program at the load balancer, selects an appropriate device based on the load status of the device running the server program, etc. To distribute. The load balancer individually associates the connection of the client side device with the connection of the server side device and holds the data. When receiving a processing request from the client side device, the load balancer transfers the processing request to the server side device with which the connection is associated, and when receiving a response from the server side device, transfers the response to the corresponding client side device. To do. When the load balancer is used, the client side device is unaware of the address of the server side device, and is conscious of only the address of the load balancer. It is undefined to which server device the processing request from the client side device is transferred.

  Here, load distribution of communication using the reliable messaging method cannot be realized using a load distribution apparatus. (Ii) In order to prevent duplication, the communication program on the receiving side stores the identifier of the previously received message, and this identifier is used when the same message is transmitted from the communication program on the transmitting side. This is because it is determined whether or not it is a duplicate reception. When a message retransmitted from the communication program on the sending side passes through the load balancer and is transferred to another server side device, it is a message that has not been received before by the communication program on the receiving side of the transferred device. This is because a message is passed to the server program and duplicate processing occurs. Therefore, as shown in Patent Document 2, a unique load balancing method is used in the messaging method that achieves high reliability.

JP 2005-56260 A Japanese Patent Laid-Open No. 2005-25481

  As described above, in the prior art, a unique method is used for load distribution of communication using a reliable messaging method that “assures one-time message transmission reliably”. In the original method, there is a problem that it is necessary to transfer the load information on the server side to the communication program on the client side, and a network load is applied. In addition, when there is a communication method that does not require high reliability using a load distribution device in the system, two load distribution mechanisms are operated, and the operation load increases.

  In addition, (ii) messaging that achieves high reliability by sharing the location for storing the identifiers of messages previously received by the server-side communication program for the purpose of preventing duplication among a plurality of server-side communication programs. A load balancer can be used in the system. However, since shared data is updated from a plurality of server devices, resource access contention occurs, and there is a problem that the effect of processing the server devices in a distributed manner is reduced.

  An object of the present invention is to solve the above-described problems, apply a load distribution device to message-type load distribution, and perform a message processing in which a receiving side information processing apparatus to which a processing request is transferred causes little resource contention with each other Is to provide.

  The present invention provides a message communication system that implements load distribution when sending and receiving messages, and when the request message retransmission flag is ON, the request message is referred to by referring to the message reception state table of all information processing apparatuses on the receiving side. This is to determine whether it is valid.

  In the message communication system of the highly reliable messaging system of the present invention, the transmission side communication program of the client node (transmission side information processing apparatus) provides a retransmission flag field in the identification information of the request message, and sets the retransmission flag to ON when the message is retransmitted. The set request message is transmitted to the server node (reception side information processing apparatus) via the load balancer.

  The server side receiving side communication program stores a message receiving state table that records the received message state for determining duplicate message reception in a storage area common to a plurality of server nodes, and the message receiving state corresponding to each receiving side communication program. A message reception state management unit storing pointer information indicating the position of the table is provided in the storage area.

  Then, the reception side communication program of the server node checks whether the retransmission flag of the identification information of the request message received from the transmission side communication program of the client node via the load balancer is set to ON, and sets the retransmission flag to ON. In addition to the message reception status table corresponding to the reception side communication program that received the request message, any reception side communication program refers to the message reception status table corresponding to another reception side communication program. The received request message is valid only when no message is received. As a result, the load from the transmission side communication program can be load-balanced by the load balancer while realizing (ii) duplication prevention in the reliable messaging.

  As described above, in the present invention, it is possible to realize messaging type load distribution that achieves high reliability by using the function of the load distribution apparatus. Since there is no need to use a unique load balancing method of the messaging method that achieves high reliability, there is no increase in network traffic due to server-side load information transfer. In addition, since the same device as the load distribution device used in the communication method requiring low reliability can be used, the load distribution operation can be shared.

  According to the present invention, it is possible to apply a load distribution apparatus to load distribution, and to process a request message including a retransmission with which a receiving side information processing apparatus to which a processing request has been transferred causes little resource contention with each other.

  Hereinafter, a message communication system according to an embodiment that realizes load distribution when a message is transmitted and received by reliable messaging will be described.

  FIG. 1 is a diagram showing a configuration of a message communication system according to the present embodiment. As shown in FIG. 1, the message communication system according to the present embodiment includes a plurality of client nodes 10 that issue processing requests, a server node 13 that processes processing requests, and a load balancer 120 that distributes the processing requests to a plurality of server nodes 13. All components are connected via a network or a LAN.

  The client node 10 includes a CPU 12 and a memory 11, and the memory 11 includes a transmission side communication program 102 that performs highly reliable messaging communication with the client program 101. When the transmission side communication program 102 receives a processing request from the client program 101, The request message 150 is transferred to the load balancer 120 by a communication device (not shown) (121).

  When the transmission side communication program 102 transfers the request message 150, the request message 150 is temporarily stored in the transfer queue 105 until the response message 153 corresponding to the request message 150 is received (124). The transmission log 104, which is information for identifying, is stored in the transmission log storage unit 103. The request message 150 includes a processing request 152 specified by the client program 101 and identification information 151 that uniquely identifies the request message 150.

  The load balancer 120 transfers the received request message 150 to the receiving communication program 132 arranged in the selected server node 13 (122).

  The server node 13 includes a CPU 135 and a memory 134, and the memory 134 includes a reception-side communication program 132 and a server program 131. The receiving side communication program 132 determines the destination queue 133 from the identification information 151 of the received request message 150, stores the processing request 152 that is a component of the request message 150, and stores the identification information 151 that is a component of the request message 150. After storing the message in the message reception state table 142, a response message 153 is transmitted to the load balancer 120 by a communication device (not shown) (123). The server program 131 receives the transferred processing request 152 from the receiving side communication program 132.

  Message reception state tables 142 corresponding to all server nodes 13 are stored in the message reception state storage unit 14 and pointed to by the message reception state management unit 141. The message reception state storage unit 14 can be referred to from all server nodes 13.

  In this embodiment, the transmission side communication program 102 and the reception side communication program 132 for causing the client node 10 and the server node 13 to function as a transmission side communication processing unit and a reception side communication processing unit are stored on a recording medium such as a CD-ROM. It is assumed that after being recorded and stored in a magnetic disk or the like, it is loaded into a memory and executed. The recording medium for recording the program may be a recording medium other than the CD-ROM. The program may be used by installing it from the recording medium into the information processing apparatus, or the program may be used by accessing the recording medium through a network.

  FIG. 2 is a diagram illustrating the configuration of the transmission log 104, the identification information 151, the message reception state management unit 141, and the message reception state table 142 according to this embodiment. The transmission log 104 of the present embodiment is the same as the request message 150 previously transmitted when the same request message 150 is retransmitted when the response message 153 corresponding to the request message 150 is not returned or when a negative response is returned. Information to be added to the request message 150 to indicate that it is a message is stored.

  The transmission log 104 includes an area of a destination queue 211 indicating the destination of the request message 150, a message identification serial number 212 that uniquely identifies the request message 150, and a message pointer 213 that points to the message body that is the content of the processing request 152. . In the transmission log 104, records 2101 and 2102 exist for each message waiting to receive the corresponding response message 153 by transmitting the request message 150, and the message bodies 2103 and 2104 are pointed from the message pointer 213 of each record.

  The identification information 151 is information for uniquely identifying the request message 150. The client identification information 221 for identifying the transmission source communication program 102 of the transmission source, the destination queue 222 indicating the final destination of the request message 150, the message identification number 223, the retransmission A retransmission flag 224 indicating whether the message has been received.

  The message reception state management unit 141 indicates the storage position of the message reception state table 142 corresponding to each server node 13, and the server identification information 231 for identifying the server node 13 and the message pointing to the position of the message reception state table 142 The reception status table pointer 232 area is used. Records 2301 and 2302 exist for each message reception state table 142.

  The message reception state table 142 includes areas of a destination queue 222 indicating the final destination of the request message 150, client identification information 221 for identifying the transmission side communication program 102 of the transmission source, and a message identification number 223. Each record 2401 to 2404 exists in the received request message 150 unit. Normally, these records are deleted at the timing determined by the system such as “elapse of specified time”, “until the next request message 150 is received from the same client node 10 in the same destination queue 133”, and the like. The receiving-side communication program 132 stores the identification information 151 of the received request message 150 in the message reception state table 142, so that it can be determined that the same request message 150 has been retransmitted. .

  FIG. 3 is a flowchart showing the processing procedure of the request message 150 transmission processing in the transmission side communication program 102 of the present embodiment. FIG. 3 illustrates a flow of transmission processing of the request message 150 in the transmission side communication program 102.

  Upon receiving a message transmission processing request from the client program 101 (step 30), the transmission side communication program 102 of the client node 10 assigns a message identification serial number that uniquely identifies the message (step 31), and creates a transmission log 104 After that, the processing request message is stored in the transfer queue (step 32), and the transmission log is stored in the transmission log storage unit 103 (step 33). The request message 150 is assembled from the processing request 152 and the transmission log 104 stored in the transfer queue 105 on the memory 11 (step 34), and the created request message 150 is transmitted to the server node via the load balancer 120 by the communication device. 13 (step 35).

  Thereafter, it is determined whether the response message 153 is received within the set time from the receiving side communication program 132 of the server node 13 (step 36). If the response message 153 is received, the processing request message is deleted from the transfer queue 105 ( Step 37), the corresponding transmission log 104 is deleted (Step 38), and the message transmission process is terminated (Step 39).

  On the other hand, if it is determined in step 36 whether or not the response message 153 has been received within the set time from the receiving side communication program 132 of the server node 13, if the response message 153 has not been received, the request message 150 is retransmitted to retransmit. The flag 224 is set to ON and the request message 150 is assembled on the memory 11 (step 341), and the request message 150 is transmitted to the server node 13 via the load balancer 120 by the communication device (step 35).

  FIG. 4 is a flowchart showing the processing procedure of the request message 150 reception processing in the receiving side communication program 132 of the present embodiment. FIG. 4 explains the flow of the reception process of the request message 150 in the reception side communication program 132.

  When receiving the request message 150 (step 40), the receiving side communication program 132 of the server node 13 determines whether the retransmission flag 224 in the identification information 151 is ON (step 41). If the retransmission flag 224 is not ON, It is determined whether there is the same identification information 151 as the request message 150 in the message reception state table 142 associated with the receiving side communication program 132 of the server node 13 (step 42).

  If there is no identification information 151 that is the same as the request message 150 in the message reception state table 142, the processing request 152 of the request message 150 is stored in the destination queue 133 (step 43). Next, the identification information 151 of the request message 150 is stored in the message reception state table 142 (step 44). Thereafter, the response message 153 is transmitted to the transmission side communication program 102 of the client node 10 (step 45), and the request message reception process is completed (step 46).

  On the other hand, if it is determined in step 42 whether or not the same identification information 151 as the request message 150 exists in the message reception state table 142, if the same identification information 151 exists, it means that the corresponding message has been received before. The response message 153 is transmitted to the transmission side communication program 102 without storing the identification information 151 and the processing request 152 (step 45).

  In addition, as a result of determining in step 41 whether or not the retransmission flag 224 in the identification information 151 of the received request message 150 is ON, if the retransmission flag 224 is ON, there is a possibility that the corresponding message has been received before. In order to check all the message reception status tables 142, the message reception status table 142 located at the head of the message reception status storage unit 14 is pointed (step 411).

  Then, it is determined whether or not the pointed message reception state table 142 has the same identification information 151 as that of the request message 150 (step 412). If there is the same identification information 151, it means that the corresponding message has been received before, and the response message 153 is transmitted to the transmission side communication program 102 without storing the identification information 151 of the request message 150 or the processing request 152 (step 45). ).

  If the same identification information 151 does not exist, it is determined whether the currently received message reception state table 142 is the last message reception state table 142 (step 413). If it is the last message reception state table 142, the received request is received. It is determined that the message 150 has not been received so far, the processing request 152 of the request message 150 is stored in the destination queue 133 (step 43), and the identification information 151 of the request message 150 is stored in the message reception state table 142. Store (step 44). Thereafter, a response message 153 is transmitted to the transmission side communication program 102 of the client node 10 (step 45), and the request message reception process is terminated (step 46).

  On the other hand, if the message reception status table 142 that is pointed to is not the last message reception status table 142, the message reception status table 142 located next is pointed (step 414). It is determined whether the pointed message reception state table 142 has the same identification information 151 as the request message 150 (step 412), and the check of all the message reception state tables 142 is repeated.

  As described above, according to the message communication system of the present embodiment, whether the request message is valid by referring to the message reception state table of all information processing apparatuses on the receiving side when the retransmission flag of the request message is ON. Therefore, it is possible to apply a load balancer to load distribution in the reliable messaging system, and to process request messages including retransmissions without causing resource contention between the receiving side information processing devices to which processing requests are transferred It is.

It is a figure which shows the structure of the message communication system of this embodiment. It is a figure which shows the structure of the transmission log 104 of this embodiment, the identification information 151, the message reception status management part 141, and the message reception status table 142. FIG. It is a flowchart which shows the process sequence of the request message 150 transmission process in the transmission side communication program 102 of this embodiment. It is a flowchart which shows the process sequence of the request message 150 reception process in the receiving side communication program 132 of this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Client node, 11 ... Memory, 12 ... CPU, 101 ... Client program, 102 ... Transmission side communication program, 103 ... Transmission log storage part, 104 ... Transmission log, 105 ... Transfer queue, 120 ... Load balancer, 13 ... Server node 131... Server program 132... Reception side communication program 133... Destination queue 134. Memory 135 135 CPU 14 message reception state storage unit 141 message reception state management unit 142 message reception state table 150 ... request message 151 ... identification information 152 ... processing request 153 ... response message 211 ... destination queue 212 ... message identification sequence number 213 ... message pointer 2101 and 2102 ... record 2103 and 2104 ... message body, 221 Client identification information, 222 ... Destination queue, 223 ... Message identification sequence number, 224 ... Retransmission flag, 231 ... Server identification information, 232 ... Message reception state table pointer, 2301 and 2302 ... Record, 241 ... Destination queue, 242 ... Client identification information 243 ... Message identification sequence number, 2401 to 2404 ... record.

Claims (5)

In a message communication method that realizes load balancing when sending and receiving messages,
The request message identification information includes retransmission information indicating whether or not retransmission, and a request message including retransmission information indicating retransmission at the time of message retransmission is transmitted by the communication device,
When retransmission information indicating that the request message is not retransmitted is set in the identification information of the received request message, the identification information of the request message is stored in the message reception state table of the receiving information processing apparatus by the storage device,
When retransmission information indicating retransmission is set in the identification information of the received request message, the message reception state table of the information processing apparatus on the receiving side is referred to by the storage device, and the identification information of the request message is received as a message. A message communication method comprising: determining whether the request message is valid according to whether it is already stored in a state table.   When retransmission information indicating retransmission is set in the identification information of the received request message, the message reception status table of all the receiving side information processing devices is referred to by the storage device. If it is not stored in any message reception status table of the receiving side information processing apparatus, the storage device stores the identification information of the request message in the message reception status table of the receiving information processing apparatus that has received the request message. The message communication method according to claim 1, wherein:   When retransmission information indicating retransmission is set in the identification information of the received request message, the message reception status table of all the receiving side information processing devices is referred to by the storage device. When stored in any message reception status table of the receiving side information processing device, a response message to the request message is transmitted by the communication device without storing the identification information of the request message in the message reception status table The message communication method according to claim 1, wherein the message communication method is performed. In a message communication system that realizes load balancing when sending and receiving messages,
A transmission side communication processing unit that includes, in the identification information of the request message, retransmission information indicating whether or not retransmission, and a request message including retransmission information indicating retransmission at the time of message retransmission;
When retransmission information indicating non-retransmission is set in the identification information of the received request message, the identification information of the request message is stored in the message reception state table of the information processing apparatus on the receiving side by the storage device and received. When retransmission information indicating retransmission is set in the identification information of the request message, the message reception state table of the reception side information processing device is referred to by the storage device, and the identification information of the request message is the message reception state table A message communication system comprising: a reception side communication processing unit for determining whether the request message is valid depending on whether the request message is already stored in the message communication system. In a program for causing a computer to execute a message communication method that realizes load balancing when sending and receiving messages,
The request message identification information includes retransmission information indicating whether or not retransmission, and a request message including retransmission information indicating retransmission at the time of message retransmission is transmitted by the communication device,
When retransmission information indicating that the request message is not retransmitted is set in the identification information of the received request message, the identification information of the request message is stored in the message reception state table of the receiving information processing apparatus by the storage device,
When retransmission information indicating retransmission is set in the identification information of the received request message, the message reception state table of the information processing apparatus on the receiving side is referred to by the storage device, and the identification information of the request message is received as a message. A program for causing a computer to execute a process of determining whether or not the request message is valid depending on whether it is already stored in a state table.

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