JP4981952B2 - Distributed computing system - Google Patents

Description

  The present invention relates to a technique for selecting a reader in a distributed computing system.

In recent years, with the development of communication networks, distributed computing systems represented by cloud computing have been developed. In this distributed computing system, a plurality of servers execute their respective processes concurrently and communicate with each other via a network.
In such a distributed computing system, even if a failure occurs in a server constituting the system, it is required to continue the service provided. In general, a redundant configuration is employed.
In the distributed computing system, when a failure occurs in the current server, it is necessary to newly select a leader from the standby server group. As a conventional method for selecting a leader, there is a method for selecting a new leader from a membership list stored in a name server ordered in the order of addition of processors in a processor group (Patent Document 1).

Japanese Patent Laid-Open No. 10-40226

  However, in the conventional method, since a new leader is selected from the membership list stored in the name server, it becomes impossible to select a leader when the name server becomes unavailable due to a failure or the like. There was a problem that a leader could not be selected.

  The present invention has been made in order to solve the above-described problems, and is a distributed computing that can quickly and autonomously select a reader without depending on a specific server such as a name server. The purpose is to provide a system.

In order to solve the above problems, the distributed computing system of the present invention (hereinafter referred to as “the system”) forms an agreement in which a plurality of information processing apparatuses are partly led by Paxos and others are agents. In a distributed computing system that performs tasks using predetermined data in accordance with an instruction from a client, transmission time data and each of the information processing apparatuses other than itself participate in the distributed computing system. Communication data transmission device for transmitting transmission data including the joined time through the network at a desired time interval, and from each information processing device other than itself at a desired time interval through the network. A transmitted communication data receiving device for receiving transmitted data having the same structure as the transmitted data; A reader selection necessity detection device that detects that the reader selection is necessary, and a connection that is the number of each information processing device other than itself that maintains communication with itself when the reader selection is necessary Information for counting the number of maintenance information processing devices and determining whether the number of connection maintenance information processing devices is greater than or equal to a majority of the initial total number of information processing devices that are subscribed at the start of operation of the distributed computing system Compare the joining time of each information processing device other than the processing device number discriminating device and the information processing device recorded in the transmitted data with the own joining time, and the information processing device which is the oldest joining time. selected as leader candidate information processing apparatus, for each information processing apparatus other than the own, a reader candidate selection unit for transmitting identification information of the reader candidate information processing apparatus, wherein Check the identification information of the candidate reader information processing device received from each information processing device other than the person and the identification information of the candidate reader information processing device transmitted by itself, and information more than a majority of the initial total number of the information processing devices A reader recognition device that recognizes the information processing device as a new reader when the same information processing device is recognized as a leader candidate information processing device by the processing device; is recognized the information processing apparatus is characterized in Rukoto is selected as the leader in the system by.

  In the distributed computing system, the leader candidate selection device operates when the number of the connection maintenance information processing devices is a majority of the initial total number of the information processing devices, that is, the connection maintenance information processing. When the number of devices is more than a majority of the initial total number of the information processing devices, compare the joining time of each information processing device other than the own recorded in the transmitted data with the own joining time, A reader candidate selection device that selects the information processing device having the oldest joining time as a leader candidate information processing device and transmits identification information of the leader candidate information processing device to the reader candidate information processing devices other than the own candidate time. It can also be set as the structure provided with.

  According to the present invention, when it is detected by the reader server selection necessity detection device that the reader selection is necessary, each information other than the one whose communication is maintained with the information processing device number determination device. The number of processing devices (number of connection maintaining information processing devices) is counted, and it is determined whether or not the number of connection maintaining information processing devices is equal to or greater than a majority of the initial total number of information processing devices. Then, when the condition is satisfied by the leader candidate selection device, the information processing device recognized by itself and other information processing devices has the oldest time of joining this system (the longest subscription period). The information processing apparatus is transmitted as the leader candidate information processing apparatus and as another information processing apparatus. Further, the other information processing apparatus that has received the data of the candidate reader information processing apparatus uses the same information processing that is recognized by the reader recognition apparatus as a leader candidate information processing apparatus by more than a majority of the initial total number of information processing apparatuses. When the apparatus exists, the information processing apparatus is recognized as a new reader.

  In the present invention, the reader can be selected autonomously without receiving an instruction from a third party or the like by the series of operations described above.

  In addition, since the leader candidate selection device selects the information processing device with the oldest time of joining, reader replacement is not performed by a server that has joined the system later, so frequent reader replacement may be suppressed. it can.

Furthermore, in the present invention, the number of information processing devices other than the device that is in communication with itself (the number of connection maintaining information processing devices) is calculated, and the number of connection maintaining information processing devices is the initial total number of information processing devices. Satisfying the condition of whether or not it is greater than or equal to the majority (conditions by the number of information processing devices, hereinafter referred to as “first condition”), and information processing devices that are greater than or equal to the initial total number are recognized as leader candidate information processing devices. That the same information processing apparatus is present (condition by the reader recognition apparatus, hereinafter referred to as “second condition”) is set as a condition for selecting a new reader.
According to the first condition, since the presence of information processing devices that are more than a majority of the initial total number is set as a condition for starting selection of leader candidates, disturbance of reader selection by information processing devices that are less than the majority can be prevented. In addition, according to the second condition, selection of an incorrect leader candidate can be prevented, and the leader can be selected reliably.

  In the distributed computing system, it is preferable that the communication data transmission device transmits the transmission data with the information processing devices at regular time intervals.

  According to the present invention, the communication data transmitting device transmits transmission data to and from each information processing device at regular time intervals, and constantly confirms the communication state with each information processing device. The case where re-selection is needed can be detected quickly and the subsequent processing can be performed.

  According to the present invention, it is possible to provide a distributed computing system capable of autonomously selecting a reader without depending on a specific server.

1 is a schematic diagram showing a distributed computing system of the present invention. It is a block diagram which shows a part (a reader server and two agent servers) of the distributed computing system of this invention. It is a block diagram which shows a part of server which is a component of the distributed computing system of this invention. (A) It is a conceptual diagram of HB communication data. (B) It is a conceptual diagram of leader server candidate data. (C) It is a conceptual diagram of leader server candidate absent data. It is a flowchart which shows operation | movement of the distributed computing system of this invention. It is explanatory drawing which shows the state at the time of the reader server selection necessity of the distributed computing system of this invention in this embodiment.

An embodiment for carrying out the present invention (hereinafter referred to as “embodiment”) will be described in detail with reference to the drawings.
The distributed computing system S of the present invention is configured by connecting a plurality of servers (information processing apparatuses) via a network N such as the Internet and a LAN (reference numeral L). Hereinafter, for convenience of explanation, one reader server E (old reader server) and four agent servers A to D (hereinafter, five servers may be collectively referred to as “each server”) are examples. Will be described.

  The servers A to E have been described with different names, but the configuration is the same, and each server can play the role of another server in response to a request from the client K. Yes. Therefore, in describing the same component, in principle, when the component is collectively referred to, the same symbol is attached, but when it is necessary to indicate the difference of the component due to the difference of servers, the symbol Furthermore, it distinguishes by attaching | subjecting A-E to the tail.

[Overall Configuration of Distributed Computing System S]
As shown in FIGS. 1 and 2, the distributed computing system (hereinafter referred to as “the present system”) S of this embodiment is composed of five servers A to E. The servers A to E are communicably connected to each other, and are connected to a client K that knows their IP addresses via a network N. Each of the servers A to E receives an instruction from the client K for data stored in the same database DA to DE, and issues an operation command such as arithmetic processing via an operation execution means (not shown). By executing, a desired task can be performed.

Here, an application program for executing the operation command and a program for distributed computing for distributed processing of tasks are installed in the servers A to E, respectively.
Each of the servers A to E is a general-purpose computer and includes a CPU (not shown). For convenience of explanation, as shown in FIG. It is configured so that it can be divided into consensus forming units 4A to 4E and execution units 5A to 5E (only servers A, C, and E are shown).

  The agreement forming units 4A to 4E constitute a Paxos device P for forming an agreement with Paxos that is known inside the cell. In this Paxos device P, before each server constituting the cell becomes a reader server E or agent server A to D and this system S executes a certain operation command, more than half (or more than a quorum) servers operate the server. This is a consensus algorithm in which the leader server E consults whether or not to agree to execute a command, and starts execution if an agreement is formed. By such an algorithm, synchronization between servers can be easily achieved, and the apparatus can realize high availability.

  In the Paxos apparatus P, a task agreed upon by a majority of servers or more can be executed in accordance with the distributed computing program (this point is not described in detail). Further, according to the distributed computing program, each of the consensus building units 4A to 4E can pass metadata by a communication method (for example, UDP) within a predetermined band.

  The operation command is determined by the Paxos device P, and the execution units 5A to 5E can execute the task by applying a predetermined operation command to the application program.

[Premise of this system S]
As described above, the reader server E plays a very important role in the execution of the present task in the Paxos apparatus P constituting this system.
When executing this task, the client K can inquire which server is the reader server to each of the servers A to E. Since the client K knows the IP addresses of the servers A to E, it can know whether or not the server is a reader server from any of those servers. If the reader is absent for some reason (such as a failure of the reader server) (including the case where no reader has been selected in the initial state), a new reader server is selected immediately. Although necessary, this system S is a system for realizing selection of the reader server.

  As shown in FIG. 3, the present system S includes a communication data control device 10, a communication device 30, a reader server selection device 60, and the like in order to configure a system for selecting a reader server.

(Communication data control device 10)
The communication data control device 10 is means for controlling transmission / reception of various data via the data transmission device 40 and the data reception device 50 which are the communication devices 30. The HB communication control device 20 (however, HB is “heart” Abbreviation of “beat”.) The HB communication control device 20 is a device that controls heartbeat communication for maintaining bidirectional communication with all servers other than itself among various types of communication data, and further, an HB communication data creation device 21. The HB communication status confirmation device 22 and the HB communication data storage device 23 are provided.

The HB communication data creation device 21 is a device for creating HB communication data (corresponding to transmission data and transmitted data in claims) for performing heartbeat communication.
The “HB communication data” is a transmission time stamp (transmission time data) (hereinafter referred to as “transmission time time”) based on a device number of a transmission source server and a device number of a transmission destination server, and a time measurement function of the transmission source server. The transmission time stamp (hereinafter referred to as “stored transmission”) transmitted from the transmission source of the HB communication data stored in the HB communication data storage device 23, which will be described later, from the transmission source of the HB communication data. (It is referred to as “time stamp”.) (However, it is “0” because it does not exist at the time of the first communication) (details will be described later), and the time stamp of the date and time when the device itself joined this system S (hereinafter “subscription time stamp”). At least) (FIG. 4A).

  In the claims, transmission data and transmitted data are distinguished. However, each server A to E is an apparatus having the same configuration, and since each server A to E communicates with each other, the structure of each HB communication data is the same. It is only used.

The HB communication data transmission device 41 (communication data transmission device) forms part of the data transmission device 40, and transmits the HB communication data created by the HB communication data creation device 21 to each server other than itself. It is a device for.
For example, in the present embodiment, the reader server E continues to transmit HB communication data to the agent servers A to D other than itself at a predetermined time interval (Δt). Further, like the reader server E, the other agent servers A to D continue to transmit HB communication data to the servers A to E other than itself.

  The HB communication data receiving device 51 (communication data receiving device) forms part of the data receiving device 50, and receives HB communication data transmitted from the HB communication data transmitting device 41 of a server other than itself. The device is always operating.

The HB communication data storage device 23 receives the HB communication data transmitted from each of the servers A to E as the transmission source via the HB communication data reception device 51, and temporarily stores the data in a readable manner. Device.
Each of the servers A to E can store the transmission time stamp of the transmission source server of the HB communication data as a stored transmission time stamp. The stored transmission time stamp can be read out when the HB communication data is created by designating the transmission source server as the transmission destination.

  Further, the HB communication state confirmation device 22 described later constantly monitors whether or not the communication state is maintained with each server. If the communication state is maintained, the HB communication data storage device 23 is maintained. Can store the transmission source device number and the subscription time stamp in association with each other.

The HB communication status confirmation device 22 cooperates with the HB communication data transmission device 41 and the HB communication data reception device 51 to determine whether or not bidirectional communication has been established between itself and each server other than itself. It is an apparatus for judging.
As described above, for example, the HB communication data transmission device 41E of the reader server E transmits HB communication data to the agent servers A to D other than itself at a predetermined time interval (Δt). The destination agent servers A to D continue to receive the HB communication data as long as a failure or the like has occurred and cannot be received. Thus, the HB communication data continues to be transmitted at the same time interval (Δt) (however, the transmission start times may not match).

Under such circumstances, the HB communication state confirmation device 22 can determine whether or not HB communication is established between the servers by making the following determination.
That is, since each server performs communication at the same time interval (Δt), assuming that a predetermined communication time between servers (hereinafter referred to as “inter-server communication time”) is Δd, communication is performed. Is established, the HB communication data is transmitted from the agent servers A to D during the time 2Δd to Δt + 2Δd after the reader server E transmits the HB communication data.

  By the way, in the HB communication data of the agent servers A to D, a stored transmission time stamp which is a transmission time one point before the reader server E which is a transmission destination of the HB communication data is recorded, and the stored If the difference between the transmission time stamp and the reception time of the HB communication data is defined as an HB response time for convenience, the HB response time is Δt + 2Δd + predetermined margin time (this value is referred to as “HB communication state determination reference time value”). It is possible to determine whether or not HB communication is established based on whether or not the following is true. Therefore, in this apparatus, if the HB response time is equal to or less than the HB communication state determination reference time value, it is determined that the two-way communication is secured between the servers, and if it is larger than that, the two-way communication is blocked. It can be judged that there is.

  Since the stored transmission time stamp and the reception time of the HB communication data are recorded by the time keeping function of the same server, the HB response time can be easily calculated by taking the difference between the two times. ing.

(Communication device 30)
The communication device 30 includes a data transmission device 40 and a data reception device 50, and is a device for communicating various data such as HB communication data and leader server candidate data via the communication network N.

(Leader server selection device 60)
The leader server selection device 60 is a device for autonomously selecting a new leader server when a new leader server (hereinafter referred to as “new leader server”) needs to be selected. A selection necessity detection device 61, a server connection state determination device 62 (connection maintenance information processing device number determination device), a leader server candidate selection device 63, and a reader server recognition device 64 are provided.

The reader server selection necessity detection device 61 recognizes that the reader server E does not exist in the initial state when the system S starts operation, and transmits the HB communication data between the servers. The system S is constantly monitored and the old reader server that has been isolated due to the communication failure is transferred to the system S because the transmission of the HB communication data from the reader server E that has been recognized as the reader is interrupted. By recognizing that it has returned, it is determined that it is necessary to select a new leader server, and this is the device for starting the processing for that purpose.
In the reader server selection necessity detection device 61, the initial state, the recovery state of the previous reader server, and the HB response time in the reader server E recognized so far in the HB communication state confirmation device 22 are the HB communication state. When the determination reference time value is exceeded, it is determined that the HB communication from the reader server E is interrupted, and in this case, the connection server state determination device 62 confirms the communication state between the servers A to D. Can be ordered.

  The server connection status determination device 62 indicates the number of servers whose communication status is confirmed to be maintained by the HB communication status verification device 22 (hereinafter referred to as “number of communication maintenance servers”) as the HB communication storage device 23. The number of communication maintenance servers is the total number of servers subscribed to the system S at the time when the operation of the system S is started (hereinafter referred to as “initial total number of servers”). It is an apparatus for discriminating whether or not it is more than a majority.

In the server connection state determination device 62, when the above conditions are satisfied, the leader server candidate selection device 63 is instructed to select a leader server candidate. When the conditions are not met, the leader server candidate selection device 63 selects the leader server candidate. It is determined that the user is absent, and information indicating that the leader server candidate is absent can be notified to the leader server candidate selection device 63.
Note that the initial total number of servers is stored in advance in a storage device (not shown).

  The leader server candidate selection device 63 selects a leader server candidate when the server connection state determination device 62 is instructed to select a leader server candidate, and with respect to other servers via the data transmission device 40, It is a device for notifying a command for transmitting the information.

In the leader server candidate selection device 63, among the subscription time stamps of the servers A to E (including itself) stored in the HB communication data storage device 23, the subscription time is the oldest (the subscription in the present system S is the oldest). A server with a long time) (hereinafter referred to as the “longest aged server”), and the reader server candidate data including the device (identification) number data is created with the longest aged server as a candidate for the candidate reader server. The data transmission device 40 can be ordered to transmit to each server.
When there is a server with the same subscription time, the longest server is determined according to a predetermined determination criterion (for example, the server that made the last determination is determined as the longest server). It will be.

  On the other hand, when information indicating that the leader server candidate is absent is transmitted from the server connection state determination device 62, the leader server absence information (for example, “−1”) is used instead of the device number data of the longest server. ) Is recorded, and a command for transmitting the information to another server other than itself is notified via the data transmission device 40. Has been.

  The “leader candidate data” and the “leader candidate absent data” include at least the device number of the transmission source server, the device number of the transmission destination server, the device number of the longest server, or leader server absence information (FIG. 4 ( b), (c)).

The leader server recognizing device 64 checks the device number of the longest old server recorded in the leader server candidate data received from another agent server and the device number of the longest old server recognized by itself to determine the initial total number of servers. If there is a server that is recognized by more than half of the servers as candidate leaders, the server is instructed to recognize the server as a new leader server (hereinafter referred to as “new leader server”). Device.
On the other hand, the longest old server is checked, and if there is no server that is recognized as a leader candidate by more than half of the initial total number of servers, the new leader server is not recognized.

By transmitting the leader server candidate, each server involved in the selection of the new leader server recognizes which server has become the new leader server, and the agent server issues a command from the new leader server. Received tasks and so on.
Each server involved in the selection of a new leader server can transmit the device number of the new leader server when an inquiry about the new leader server is received from the client K.

[Operation]
Next, the operation of the system S will be described with reference to FIG.
In the initial state where the operation of the system S starts, the reader server selection necessity detection device 61 detects that the reader server E does not exist, and is almost the same as the following. Since the reader server E is recognized by the operation (S1, S2), the following will describe the reader selection during the operation of the system S.

In the initial state, the reader server E and the agent servers A to D execute a task according to a predetermined application in response to a request from the client K. At this time, it is confirmed that the HB communication is maintained by transmitting and receiving the HB communication data between the servers A to E.
In addition, the continuous line in FIG. 6 has shown that communication of each server is maintained, and x mark has shown that communication is interrupted | blocked. In addition, () indicates the time of joining the system S, and the joining times of the agent servers A to D are sequentially delayed by 1 hour, 1:00, 2:00, 3:00, 4:00. (The month and day are assumed to be the same day and are omitted).

  Now, it is assumed that the reader server E stops operating for some reason and leaves the system S. Then, in the HB communication state confirmation device 22 that has been monitoring HB communication with the reader server E, the HB response time in the reader server E recognized so far exceeds the HB communication state determination reference time value. It is determined that communication between the server E and the other servers A to D is interrupted. Therefore, the reader server selection necessity detection device 61 of each agent server A to D performs an operation of selecting (selecting) a new reader server for the server connection state determination device 62, assuming that the old reader server E has disappeared. Is started (S3).

  First, each server connection state determination device 62 reads and counts the number of communication maintenance servers from the HB reception data storage device 23 (S4). In the present embodiment, the total number of communication maintenance servers of each agent server A to D is four.

Then, the server connection state determination device 62 determines whether or not the number of communication maintenance servers is equal to or greater than the majority [3] of the initial total number of servers [5] (S5). In the present embodiment, since each agent server A to D satisfies this condition, the server connection state determination device 62 of each agent server A to D determines the leader server candidate selection device 63 of the agent server A to D. A command is given to select a leader server candidate (S6).
If there is no agent server that satisfies the above conditions, the server connection state determination device 62 confirms that there is no leader server candidate for the leader server candidate selection device 63 of the agent server. Notification is made (S7).

  The leader server candidate selection device 63 of the agent servers A to D instructed to select a leader server candidate from the server connection state determination device 62 includes each server A to D (including itself) stored in the HB communication data storage device 23. The oldest server with the oldest subscription time is selected from the subscription time stamps of), and reader server candidate data is created (S8). In the present embodiment, for each of the agent servers A to D, the leader server candidate is the agent server A whose subscription time is 1:00.

  If the information indicating that the leader server candidate is absent is transmitted from the server connection state determination device 62, the leader server candidate selection device 63 of the agent server determines the device number data of the longest old server. Instead, leader server candidate absence data in which the leader server absence information (-1) is recorded is created (S9).

  The leader server candidate data or leader server candidate absent data created as described above is transmitted to each server other than itself through the data transmission device 40.

  Reader server candidate data transmitted from each of the agent servers A to D is received via the data receiving device 40. The leader server recognition device 64 includes the device number of the longest old server of the leader server candidate recorded in the leader server candidate data received from the other agent server, and the longest old server recognized by itself (to other agent servers). (The same as the oldest server sent to the server), and there is an identical agent server that is recognized as a leader server candidate by more than half of the initial total number of servers [5] [3] (S10), if the condition is satisfied, the agent server is recognized as a new leader server (S11).

  In this embodiment, in all the agent servers A to D, the device number of the longest old server recognized by itself is A, and the longest old server transmitted from each agent server A to D (excluding itself). Since the device number is also A, all the agent servers A to D recognize the agent server A as a new leader server.

  If the longest server is checked, and there is no server that is recognized by more than a majority [3] of the initial total number of servers [3] as leader candidates, a new leader server is selected. It will not be recognized (S12).

The new leader server A operates as a new leader server, and the other agent servers B to D execute tasks according to the instructions.
In addition, the client K inquires of each of the servers A to D about the new leader server, and one of the servers transmits the device number of the new leader server A, so that the client K recognizes the new leader server. be able to. Then, subsequent instructions are given to the new reader server A.

  When the old reader server that was isolated due to communication failure returns to the system S due to the recovery of the communication failure, if the old leader server is the longest old server in the system S, the same as above As a result of this operation, the device itself returns to the new reader server.

  As described above, according to the system S, a new reader server can be selected autonomously without receiving an instruction from a third party or the like by the series of operations described above. In particular, since it does not depend on a specific server, it is possible to select a new reader server without worrying about a failure of the specific server.

  In addition, the leader server candidate selection device 63 selects the oldest server with reference to the time of joining the system S. Therefore, since the selection criteria for the new reader are clear and the reader replacement is not performed by a server that has joined the system S later, unnecessary reader replacement can be suppressed, and the stability of the system S can be prevented. It will contribute to sex.

Further, in the present system S, the number of servers other than itself that maintain communication with itself is counted, and the condition (first condition) is satisfied whether or not the number of communication maintenance servers is greater than or equal to a majority of the initial total number. In addition, a condition for selecting a new leader is that there is the same server that is recognized as a leader candidate server by more than a majority of the initial total number of servers (second condition).
According to the first condition, since the presence of a server having a majority of the initial total number or more is set as a condition for starting selection of the leader candidate server, it is possible to prevent disturbance of leader selection by a server of less than the majority. Further, the second condition can prevent selection of an erroneous leader candidate server, and can reliably select a leader server.

  Further, in the present system S, the HB communication data transmitting device and the HB communication data receiving device transmit and receive HB communication data at regular time intervals, and the HB communication state confirmation device 22 monitors the communication state of each server. Thus, it is possible to quickly detect a case where a new leader selection is necessary and perform the subsequent processing.

As mentioned above, although an example about a suitable embodiment was explained about the present invention, the present invention is not restricted to the embodiment concerned, and a design change is possible suitably in the range which does not deviate from the meaning of the present invention.
In the above-described embodiment, the information processing apparatus has been described by taking the case of five servers as an example. However, the type and number of information processing apparatuses are not limited to this as long as they are a plurality of computing devices. Further, the plurality of information processing apparatuses may be connected by any connection means other than the Internet and the LAN.

  Furthermore, in the above embodiment, a case has been described on the assumption that UDP is used when performing HB communication. However, the present invention is not limited to this technique, and a communication method such as TCP may be used.

S Distributed computing system N Network K Client A to D Agent server E (Old) Reader server P Paxos device 4A, 4C, 4E Consensus building unit 5A, 5C, 5E Execution unit D Database 10 Communication data control device 20 HB communication control device 21 HB communication data creation device 22 HB communication status confirmation device 23 HB communication data storage device 30 Communication device 40 Data transmission device 41 HB communication data transmission device (communication data transmission device)
50 Data receiver 51 HB communication data receiver (communication data receiver)
60 Leader Server Selection Device 61 Leader Server Selection Necessity Detection Device 62 Server Connection State Discrimination Device (Connection Maintenance Information Processing Device Number Discrimination Device)
63 Leader server candidate selection device 64 Leader server recognition device

Claims (3)

In a distributed computing system in which a plurality of information processing apparatuses form an agreement with Paxos partly as a leader and others as agents, and perform tasks using predetermined data according to instructions from the client.
For transmitting transmission data including transmission time data and a subscription time at which the mobile communication apparatus has joined the distributed computing system to the respective information processing apparatuses other than itself at desired time intervals via the network. A communication data transmission device;
A communication data receiving device that receives transmitted data having the same structure as that of the transmission data transmitted from the information processing devices other than itself at a desired time interval via the network;
A reader selection necessity detection device for detecting that the reader selection is necessary; and
When the leader selection is necessary, the number of connection maintenance information processing devices, which is the number of each information processing device other than the device itself that is communicating with itself, is counted, and the number of connection maintenance information processing devices is the distribution A connection maintaining information processing device number determination device for determining whether or not a majority of the initial total number of the information processing devices subscribed at the start of operation of the computing system;
Compare the joining time of each information processing device other than the information recorded in the transmitted data with the own joining time, and select the information processing device having the oldest joining time as a leader candidate information processing device A reader candidate selection device that transmits identification information of the reader candidate information processing device to each information processing device other than the device itself;
The identification information of the candidate reader information processing device received from each information processing device other than the own device and the identification information of the candidate reader information processing device transmitted by itself are checked, and the majority of the initial total number of the information processing devices is greater than or equal to A reader recognition device that recognizes the information processing device as a new reader when there is the same information processing device recognized as a leader candidate information processing device by the information processing device ;
Distributed computing system in which the reader recognizes the information processing apparatus that is recognized by the device and wherein Rukoto is selected as the leader in the system.   The distributed computing system according to claim 1, wherein the leader candidate selection device operates when the number of the connection maintenance information processing devices is equal to or more than a majority of the initial total number of the information processing devices. The communication data transmitting device
The distributed computing system according to claim 1 or 2, wherein the transmission data is transmitted to and from each of the information processing devices at regular time intervals.

Images