JP5445503B2 - Information communication system and information communication method - Google Patents

Description

  The present invention relates to a data structure and search technology for searching data.

  In recent years, with the advancement of network technology, a large amount of data is stored and used on the network. Search information is used to search for content stored on the network. The search information is, for example, data attribute information. An information processing apparatus that wants to acquire data searches for desired content using the search information. Then, based on the search result, data is acquired from the information processing apparatus that stores the desired data. This attribute information includes information such as a data name and a keyword for searching for content. As the amount of data stored on the network increases, the amount of search information increases. Patent Document 1 discloses a technique in which search information is distributed and stored by node devices on a network. Specifically, a technique for managing search information using a tree structure is disclosed in order to prevent falsification of search information distributed and stored on a network. For effective distributed storage, an electronic signature is applied to the root position of the tree structure. Then, based on the electronic signature of the root position, it is possible to confirm that the search information existing at the node position or the leaf position of the tree structure is falsified.

JP 2010-262455 A

  In Patent Document 1, original data serving as a backup of search information distributed and stored is stored in a center server. When the search information is distributed and stored in a plurality of node devices, a part of the search information may be damaged due to a failure of the storage device of the node device or separation of the node device from the network. In this case, since the center server that stores the original data can provide a part of the damaged search information, the provision of the search information can be guaranteed. However, if the search information of the center server is damaged, provision of the search information cannot be guaranteed. In addition, in order to prevent the search information of the center server from being damaged, it may be considered that a plurality of RAIDs (Redundant Arrays of Inexpensive Disks) are formed, but this is not an effective measure because of the cost of increasing the center server. .

  The present invention has been made in view of the above problems. The present invention relates to an information processing apparatus, an information communication system, and an information communication method capable of providing search information by using search information distributed and stored in a network even when search information of a center server is damaged And to provide a program.

According to the first aspect of the present invention, in an information communication system in which a plurality of search information for searching for data stored in a distributed manner in a network is distributed and stored in a plurality of node devices connected to the network. The information communication system includes an information processing device that stores a plurality of search information that is distributed and stored in the plurality of node devices, wherein the information processing device is distributed and stored in the plurality of node devices. First storage means for storing a plurality of search information; first determination means for determining whether there is damaged search information among the plurality of search information stored in the first storage means; and the first determination. A first transmission unit configured to transmit a transmission request for the damaged search information to at least one of the plurality of node devices when it is determined that there is search information damaged by the unit; First receiving means for receiving damaged search information from any one of the node devices, and receiving the search information damaged in the search information stored in the first storage means by the first receiving means. Update means for updating using the retrieved search information, wherein the node device receives the transmission request, and the node device based on the transmission request received by the second reception means. An information communication system comprising: second transmission means for transmitting the search information stored in the apparatus to the information processing apparatus.

According to invention of Claim 1 , the said 1st memory | storage means memorize | stores the said search information containing the order information which shows the order in which the said search information was added, and the identification information which identifies the said search information, The information processing device is configured to store, based on the order information, the first management node that stores the search information corresponding to the order information from the plurality of node devices, or the plurality of node devices based on the identification information. A first determination unit configured to determine one of the second management nodes storing the search information corresponding to the identification information from among the node devices, wherein the first transmission unit is determined by the first determination unit; A storage request message for storing the search information corresponding to the order information or the identification information is transmitted to the first management node or the second management node; Message, characterized in that it comprises a second storage means for storing the search information indicated.

According to the first aspect of the present invention, the first determination unit determines the first management node and the second management node, and the first transmission unit is determined by the first determination unit. A save request message for saving the search information corresponding to the order information or the identification information is transmitted to the first management node and the second management node, and the node device performs the search indicated by the save request message. A second storage means for storing information is provided.

According to the first aspect of the present invention, either one of the first management node or the second management node among the plurality of node devices periodically survives toward the other node device. A third transmitting means for transmitting a confirmation message for confirming the confirmation, a third receiving means for receiving the confirmation message, and determining whether or not the confirmation message has not been received by the third receiving means for a predetermined time or more. When the confirmation message is not received for a predetermined time or more by the second determination means and the second determination means, the order information or the identification information included in the search information stored in the second storage means And a second determination unit that determines a new first management node or a second management node based on any one of the two, and the second transmission unit is determined by the second determination unit. Toward a new first management node or the second management node has, and transmits a save request message to store the search information stored in the second storage means.

According to the invention described in claim 2 , in the information communication system in which a plurality of search information for searching for data stored in a distributed manner in a network is distributed and stored in a plurality of node devices connected to the network. An information communication method comprising an information processing device for storing a plurality of search information distributed and stored in the plurality of node devices, wherein the plurality of search information stored in a distributed manner in the plurality of node devices is stored A determination step in which the information processing apparatus determines whether there is damaged search information among a plurality of search information stored in the first storage means, and determination that there is search information damaged in the determination step A first transmission step in which the information processing apparatus transmits a transmission request for search information that is damaged to at least one of the plurality of node apparatuses; and The calculated, and a second receiving step of the node device receives, on the basis of the transmission request received by said second reception step, to the node device said information processing apparatus the retrieval information stored, said node device A second transmitting step for transmitting, a first receiving step for receiving the damaged search information from any of the plurality of node devices, and a search information stored in the first storage means. the search information broken at medium, seen including a an updating step of updating by using the search information received by the first receiving step, the first storage means, indicating the order in which the retrieval information is added The search information including order information and identification information for identifying the search information is stored, and the information communication method further includes a plurality of node devices based on the order information. A first management node that stores the search information corresponding to the order information, and a second management node that stores the search information corresponding to the identification information from among the plurality of node devices based on the identification information To the first management node and the second management node determined by the first determination step and the search corresponding to the order information or the identification information A third transmission step in which the information processing apparatus transmits a storage request message for storing information; and one of the first management node and the second management node in the plurality of node apparatuses, A fourth transmission step of periodically transmitting a confirmation message for confirming survival toward the other node device; and the node device receives the confirmation message. A second receiving step for determining whether or not the confirmation message has not been received for a predetermined time or more by the third receiving step, and a second determining step for determining whether or not the confirmation message has been received by the third receiving step. The search information stored in the second storage means that is stored in the second storage means included in the node device and stores the search information indicated by the save request message when the confirmation message has not been received for a period of time The node device determines a new first management node or the second management node based on either the order information or the identification information included in the second determination step and the second determination step. A save response for saving the search information stored in the second storage means for the new first management node or the second management node that has been made. Message, the node device is a fifth transmission step and the information communication method comprising the transmission.

According to the invention described in claim 1, the first transmission unit, when it is determined that there is search information broken by the first determining means, a request for transmission of corrupted search information, a plurality of node devices Send to at least one. The update means updates the search information damaged in the search information stored in the first storage means by using the search information received by the first receiving means. As a result, even when the search information of the information processing apparatus is damaged, the search information can be updated using the search information distributed and stored in the network.

According to the invention described in claim 1, the first determination means, based on the order information, the first management node stores retrieval information corresponding to the order information from among a plurality of node devices, or the identification information Based on this, one of the second management nodes that stores the search information corresponding to the identification information is determined from among the plurality of node devices. The first transmission unit transmits a storage request message for storing the search information corresponding to the order information or the identification information toward the first management node or the second management node determined by the first determination unit. As a result, the search information stored in the information processing device is securely stored in the first management node or the second management node, so that even if the search information of the information processing device is damaged, it is distributed and stored in the network. By using the search information, it is possible to guarantee the provision of the search information.

According to the invention described in claim 1, the first determining means determines a first management node, and a second management node. The first transmission unit transmits a storage request message for storing the search information corresponding to the order information or the identification information toward the first management node and the second management node determined by the first determination unit. As a result, the search information stored in the information processing device is securely stored in the two node devices, the first management node and the second management node, so even if the search information of the information processing device is damaged, the network It is possible to reliably ensure the provision of the search information by using the search information distributed and stored.

According to the first aspect of the present invention, the second determination means includes the order included in the search information stored in the second storage means when the second determination means has not received a confirmation message for a predetermined time or more. A new first management node or second management node is determined based on either the information or the identification information. The second transmission unit transmits a save request message for saving the search information stored in the second storage unit to the new first management node or second management node determined by the second determination unit. As a result, even if either the first management node or the second management node is withdrawn from the network, a new first management node or second management node is determined, and the search information is reliably transmitted to the two node devices. Is memorized. For this reason, even when the search information of the information processing apparatus is damaged, it is possible to reliably ensure the provision of the search information by using the search information distributed and stored in the network.

According to the second aspect of the present invention, the determination step is damaged among the plurality of search information stored in the first storage unit that stores the plurality of search information distributed and stored in the plurality of node devices. Determine whether there is search information. In the update step, the search information damaged in the search information stored in the first storage means is updated using the search information received in the first reception step. As a result, even when the search information of the information processing apparatus is damaged, the search information can be updated using the search information distributed and stored in the network.

It is a figure which shows an example of the connection aspect of each node apparatus in the content distribution storage system S in this embodiment. It is a figure which shows an example of the basic structure of the catalog information which concerns on this embodiment. It is explanatory drawing explaining the outline | summary of the backup method of the catalog information of this embodiment. It is explanatory drawing explaining an example of the replication production | generation process of this embodiment. It is explanatory drawing which shows description of the page update process in this embodiment. It is a block diagram which shows the electric constitution of the node apparatus of this embodiment. It is a block diagram which shows the electric constitution of center server SA of this embodiment. It is a flowchart which shows the process sequence of the main operation | movement in center server SA. It is a flowchart which shows the process sequence of the main operation | movement in a node apparatus. It is a flowchart which shows the process sequence of the page information holding process of this embodiment. It is a flowchart which shows the process sequence of the page information deletion process of this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiment described below is an embodiment when the present invention is applied to a content distributed storage system.

[1. Outline structure and operation outline of distributed content storage system]
First, with reference to FIG. 1, the structure and operation | movement outline | summary of the content distributed storage system in this embodiment are demonstrated. FIG. 1 is a diagram illustrating an example of a connection mode of each node device in the content distributed storage system S according to the present embodiment. FIG. 1 includes a specific configuration diagram 101 of the content distributed storage system S and a conceptual configuration diagram 100. Specific Configuration of Content Distributed Storage System S As shown in FIG. 101, the content distributed storage system S includes a large number of node devices Nn (n = 1, 2, 3,...). As shown in the specific configuration diagram 101 of FIG. 1, the distributed content storage system S is configured by connecting a plurality of node devices Nn via the Internet. In addition, as shown in the lower frame 101 of FIG. 1, IX (Internet eXchange), ISP (Internet Service Provider), DSL (Digital Subscriber Line) line provider equipment, FTTH (Fiber To The Home) line provider A network NW such as the Internet is constructed by the apparatus, the communication line P, and the like. The network NW is a real-world communication network. Note that a router for transferring data packets is appropriately inserted in the network NW in the example of FIG. 1, but is not shown in FIG. 1. As the communication line P, for example, a telephone line or an optical cable is used.

  A plurality of node devices Nn are connected to such a network NW. Hereinafter, the node device is referred to as a “node”. Each node is assigned a unique manufacturing number and an IP (Internet Protocol) address. The distributed content storage system S according to the present embodiment is a peer-to-peer network system formed by any of a plurality of nodes as shown in the conceptual configuration diagram 100 of FIG. Yes.

  A network 9 shown in the conceptual configuration diagram 100 of FIG. 1 is an overlay network OL that configures a virtual link formed using an existing network NW. The overlay network OL which is a logical network is realized by a specific algorithm, for example, an algorithm using DHT. Each node connected to the distributed content storage system S is assigned a node ID, which is unique identification information having a predetermined number of digits.

  Each node holds a routing table using DHT. This routing table defines the transfer destinations of various messages on the content distributed storage system S. Specifically, a plurality of pieces of node information including node IDs, IP addresses, and port numbers of nodes that are moderately separated in the ID space are registered in this routing table. One node stores the minimum necessary node information as a routing table. By transferring various messages between the nodes, node information about nodes that do not store node information is acquired.

  The content distributed storage system S stores various content data replicas having different contents in a predetermined file format in a distributed manner in a plurality of nodes. Hereinafter, the content data is referred to as “content”. A replica can be used between the nodes. The original of each content is stored in the center server SA. A node in which a content replica is stored is referred to as a “content holding node”. In the following description, the original content and the replica are referred to as content without particular distinction.

  Information such as a content ID and content ID, which is unique identification information for each content, is added to each content described above. The ID space of the content ID matches, for example, the ID space of the node ID. The location of the content that is distributed and stored is stored as holding node information by a node that manages or stores the location of the content. Hereinafter, a node that manages or stores the location of content is referred to as a “root node”. The holding node information includes a set of node information of the node storing the content, content ID of the content, and the like. Such a root node is determined to be a node having a node ID closest to the content ID, for example. The node ID closest to the content ID is, for example, the node ID with the highest number of upper digits that match.

  In each node, attribute information such as content name and content ID of the content is described in the catalog information. The catalog information is created for each page information by the center server SA. The page information is information constituting catalog information having a tree structure. This page information is information corresponding to the nodes in the tree structure in the catalog information. Details of the structure and contents of the catalog information will be described later. Each node has an assigned range of page information to be held. The assigned range is determined based on, for example, the node ID of each node. Then, each node acquires page information within the node's own responsibility range from the center server SA or another node. Thus, catalog information is distributed and stored in a plurality of nodes in units of page information. Also, each node acquires necessary page information from the center server SA or another node when there is no necessary page information when searching for content attribute information. Note that a content acquisition method using DHT routing is known in Japanese Patent Application Laid-Open No. 2006-197400 and the like, and thus detailed description thereof is omitted.

[2. Basic structure and contents of catalog information]
Next, the basic structure and contents of catalog information will be described with reference to FIG. FIG. 2 is a diagram illustrating an example of a basic structure of catalog information according to the present embodiment. The catalog information is information for managing content attribute information as a list. This attribute information is stored in the record. The catalog information is information that can specify content from a search key. Being able to specify content means that a record of the content can be searched. The search for records is performed by the center server SA and also at the nodes. The catalog information used in the distributed content storage system S has a search tree structure in order to prevent falsification of records and to efficiently search for records.

  As shown in FIG. 2, the catalog information is configured by associating each page information from root page information located at the root in the tree structure to leaf page information located at the leaf. The directly associated page information forms a parent-child relationship. It is assumed that page information Y is associated with certain page information X. That is, it is assumed that the page information X and the page information Y form a parent-child relationship. Of the page information X and page information Y, when the page information X is shorter in distance from the root page information, the page information X is the page information of the parent located at the parent when viewed from the page information Y. Then, the page information Y becomes page information of a child positioned as a child as viewed from the page information X. Here, the distance from the root page information is a length corresponding to the number of links from the root position to the node of interest in the tree structure. In other words, the distance from the root page information corresponds to the number of page information that passes through the page information to be noticed by tracing the association from the root page information to the noticed page information. In the following description, parent page information is referred to as parent page information, and child page information is referred to as child page information.

  The association between the parent page information and the child page information is indicated in the link information. The link information is information stored in the parent page information and is information indicating child page information. This link information includes the page number of the child page information and a message digest for checking the alteration of the child page information.

  The page number is a serial number uniquely assigned to page information. For the page information, page numbers are assigned in order of creation, for example, from the first. The page information indicated by the link information means page information to which a page number included in the link information is assigned. Further, when certain page information is updated, a new page number is assigned to this page information. For example, page information is stored as a file. In this case, the file name of the page information includes the assigned page number. Thereby, the page information file can be specified from the page number. The page number of this embodiment is an example of the order information of the present invention.

  The message digest is information for checking falsification of a record stored in the child page information indicated by the link information or the child page information indicated by the link information. The message digest is a value obtained by hashing a target to be checked for tampering with a common hash function. The catalog information further includes root link information (reference numeral 100). In the root link information, link information to the root page information is stored (reference numeral 120). The link information includes the page number (reference numeral 121) and the message digest (reference numeral 122) of the root page information. The root link information stores an electronic signature (reference numeral 110). The electronic signature is information for checking whether the root link information is falsified. The electronic signature includes information such as a signature value and certificate information, for example.

  The page information is roughly classified into node page information (reference numeral 200) and leaf page information (reference numeral 300). The node page information is associated with one or more child page information. The node page information stores a page number (reference numeral 210) and link information (reference numeral 220) to child page information. The page number is a page number assigned to the node page information in which the page number is stored. A plurality of link information can be stored in the node page information. The maximum number of link information that can be stored in one section page information matches the degree as a tree structure of catalog information. This order means the maximum number of children that a parent can have. That is, the order corresponds to the value n of the n-ary search tree. The page information of the present embodiment including the search key is an example of search information in the present invention.

  As described above, the leaf page information is page information located on a leaf in the search tree. That is, the leaf page information has no child page information. The leaf page information stores a page number (reference numeral 310) and a record (reference numeral 320). The page number is a page number assigned to the leaf page information in which this page number is stored. One or more records are stored in leaf page information. One record is set with attribute information of one or more contents. For example, a content ID, a content start date / time, a content end date / time, a content name, a keyword, and the like are set in the record.

  The tree structure of catalog information has order. When a content ID is input as a search key, a search is performed according to an algorithm corresponding to the tree structure of catalog information, whereby leaf page information in which a record corresponding to the content ID is stored can be specified. As information corresponding to the order of the tree structure, an index is assigned to each page information. In order to simplify the description of the index, as an example, it is assumed that the content ID and the index are composed of a 4-digit quaternary number.

  “***” is assigned as an index to the root page information. “*” Indicates that the value of the digit is not fixed. There are a maximum of four node page information items that are children of the root page information. Each child page information is given any one of “0 ***”, “1 ***”, “2 ***”, and “3 ***” as an index. Which index is assigned to which child page information is defined in the parent page information. For example, each link information to be stored in the root page information is stored in an array structure, and a structure in which an index of page information indicated by the link information can be specified by the storage position. In this case, for example, link information indicating child page information whose index is “0 ***” is stored at a position corresponding to 0, and the index is “1 ***” at a position corresponding to 1. Link information indicating child page information is stored. Further, for example, link information and an index of page information indicated by the link information may be stored in association with the node page information. The index of this embodiment is an example of identification information of the present invention.

  The node page information located at the child of the node page information with the index “0 ***” is any one of “00 **”, “01 **”, “02 **”, and “03 **”. Is granted. Further, the page information located in the child of the node page information with the index “01 **” is, for example, leaf page information. In this case, any of “010 *”, “011 *”, “012 *”, and “013 *” is assigned to the leaf page information. The leaf page information with the index “012 *” stores records with indexes “0120”, “0121”, “0122”, and “0123”, respectively. That is, the attribute information of the content whose content ID is “0120”, “0121”, “0122”, or “0123” is stored. For example, when each record is stored in an array structure, the index can be specified by the storage position. For example, the leaf page information may store a record and an index of the record in association with each other.

  Note that the center server SA may have a function of searching for records using information other than the content ID, for example, the content name, the start date / time of publication, and the like as search keys. In this case, hint information may be stored in each node page information. The hint information is information serving as a clue to search for a record using a search key. The center server SA performs arithmetic processing on hint information and a search key according to a predetermined algorithm when searching for a record. Then, it is determined whether or not there is a possibility that a record searched by the search key is stored in the page information below the child position of the node page information in which the hint information is stored. When the center server SA determines that there is a possibility that a record searched by the search key is stored, the center server SA performs a search by referring to page information below the child position of the node page information. On the other hand, if the center server SA determines that there is no possibility that the record searched by the search key is stored, it is not necessary to refer to the page information below the child position of the node page information. Thereby, it can be judged without false negative whether or not the record searched by the search key is stored in the page information below the position of the child of the node page information. False negative refers to the property that the truth is positive but it is erroneously determined to be negative.

  Next, the reason why falsification of content attribute information can be prevented will be described. Whether or not the child page information is falsified is determined by link information to the child page information stored in the parent page information. That is, since the link information includes the message digest of the child page information, the tampering check is performed using this message digest. In this way, whether or not the child page information is falsified from the leaf page information to the root page information is checked by the link information stored in the parent page information. Whether the root page information is falsified is checked by the root link information. Whether or not the root link information is falsified is checked by an electronic signature stored in the root link information itself. Therefore, it is possible to guarantee the authenticity of the page information from the root page information to the leaf page information. As a result, falsification of the entire catalog information can be prevented.

  The structure of the catalog information described with reference to FIG. 2 is merely an example. As a structure of the catalog information, any structure may be used as long as it has a structure capable of searching for the content record. In the case where the structure of the catalog information is a tree structure, for example, records may be stored in the node page information as well as the leaf page information. The order of the tree structure, that is, the maximum number of link information that can be stored in one node page information is arbitrary. The tree type may be a balanced tree such as a B-tree, a B + tree, or a red-black tree, or may be a simple n-ary search tree having no balance. Alternatively, a tri-tree may be used.

  Further, for example, the catalog information may be a linked list structure. The catalog information having a linked list structure includes, for example, root link information and a plurality of page information. Each page information stores, for example, one or more records and one link information. The page information may store the page number or index of the page information. The index in this case is, for example, the content ID in the attribute information stored in the record. Each page information is associated with the link information, for example, in ascending order of index values. The link information indicates the next page information of the page information storing the link information. The next page information of a certain page information is page information to which an index having the next smallest value is given after the index of the certain page information. In the link information, the page number and message digest of the next page information are stored. The root link information indicates, for example, page information having the smallest index value among a plurality of page information. The root link information stores a page number of the page information, a message digest, and an electronic signature for checking tampering of the root link information.

  The following modifications can be applied regardless of the structure of the catalog information. For example, the maximum number of records that can be stored in one page information may be one or more. Further, the page number assigned to the page information need not be stored in the page information itself. In the link information, information that associates page information with each other is not limited to the page number. The root link information may not include an electronic signature. In addition, the message digest may not be included in the root link information and the link information. Further, the root link information may not be included in the catalog information. The method for adding and deleting records is well known as described in Japanese Patent Application Laid-Open No. 2010-262455, and will not be described in detail.

[3. Catalog information backup method of this embodiment]
The catalog backup method according to the present embodiment will be described below with reference to FIG. First, FIG. 3 is an explanatory diagram for explaining an overview of a catalog information backup method according to the present embodiment. First, the center server SA of the present embodiment newly performs a page information addition process on the above-described tree-structured catalog information (FIG. 3: (1)). In the page information addition process, page information including the added record is generated. In order to add a record to the catalog information having a tree structure, a new page number and an index are assigned to the generated page information. The page information of this embodiment is given a new page number and an index each time a record is updated.

  Then, the management node that manages the added page information is determined by the center server SA (FIG. 3: (2)). Since at least one node device that stores the added page information exists on the network, the management node is determined in this embodiment. Apart from the catalog information distributed and stored in the network, the management node stores the page information determined by the center server SA. In the present embodiment, the center server SA determines the hash value using the page number assigned to the added page information and the index. The hash function used at this time may be an arbitrary hash function. In the example illustrated in FIG. 3, the management node N15 is determined based on the hash value generated using the page number. In the example illustrated in FIG. 3, the management node N24 is determined based on the hash value generated using the index. Thus, in this embodiment, two management nodes are determined based on the page number and index assigned to one page information. Hereinafter, the management node managed based on the page number is referred to as a first management node. A management node managed based on the index is called a second management node. The added page information is stored by the first management node and the second management node.

  Then, the center server SA transmits a page information holding request message to the determined first management node and second management node (FIG. 3: (3)). The page information holding request message includes added page information, updated route point information, and identification information. The identification information is information for identifying whether the page information holding request message transmitted by the center server SA is a message addressed to the first management node or a message addressed to the second management node. When the page information holding request message is received, the first management node and the second management node perform a falsification check of the page information included in the received message. If no falsification has been performed, the first management node and the second management node store the page information included in the page information holding request message and the route point information (FIG. 3: (4)). At this time, based on the identification information included in the page information holding request message, it is determined whether to store in the first management list storage area or the second management list storage area. When the page information request message includes identification information indicating the address to the first management node, the page information included in the page information holding request message is stored in the first management list storage area. When the page information holding request message includes identification information indicating the address to the second management node, the page information included in the page information holding request message is stored in the second management list storage area. Details of the first management list storage area and the second management list storage area will be described later.

  When the first management node and the second management node store the page information, a periodic confirmation process is executed (FIG. 3: (5)). The periodic confirmation process is a process for periodically confirming whether or not the first management node and the second management node exist in the network. Specifically, when the first management node periodically transmits a page information holding request message to the second management node, the first management node device determines whether the second management node exists in the network. To check. The first management node uses the index of page information stored in the first management list storage area to determine a hash value using a predetermined hash function. Then, the first management node transmits a page information holding request message to the second management node determined by the determined hash value. At this time, in the page information registered in the first management list, the page information at which the page information holding request message is transmitted is associated with the time information indicating the time at which the page information holding request message is transmitted. And stored in the first management list storage area. The time information is information including the date and time when the message is sent. Either one of date and time may be used. Then, the second management node receives the page information holding request message transmitted from the first management node.

  In the present embodiment, even if the second management node receives the page information holding request message from the first management node, it does not send a response or the like. Instead, in the present embodiment, when receiving the page information holding request message, the second management node updates the reception time of the storage area that stores the page information. If the received page information does not exist in the storage area, the received page information is added. In the present embodiment, the first management node does not need to know whether the second management node exists on the network. This is because the first management node periodically sends a catalog holding request message to the second management node, so that even if the second management node leaves the network, a new second management node is determined. It is to be done.

  Then, the second management node determines that the first management node does not exist on the network when the page information holding request message is not periodically transmitted from the first management node. On the other hand, the second management node determines that the first management node exists on the network when the page information holding request message is periodically transmitted from the first management node. This makes it possible to determine whether or not the first management node and the second management node exist on the network. As a result, at least two first management nodes and second management nodes for storing the added page information exist on the network.

  Next, a process when it is determined by the confirmation process that one of the first management node and the second management node does not exist in the network will be described with reference to FIG. FIG. 4 is an explanatory diagram illustrating an example of the copy generation process according to the present embodiment. First, when it is determined by the periodic confirmation process (FIG. 3: (5)) that either the first management node or the second management node does not exist in the network, in other words, has left the network, A management node is determined (FIG. 4: (6)).

  An example will be described in which it is determined that the node N24, which is the second management node, has left the network. Then, the first management node (N15) periodically transmits a page information holding request message according to the DHT routing table (FIG. 4: (6)). The node N9 that has received the page information holding request message transmitted by the first management node (N15) newly becomes the second management node.

  In the following, an example will be described in which it is determined that the first management node has left the network. The second management node determines the hash value based on the page number based on the fact that the page information holding request message is not periodically transmitted from the first management node. Then, the second management node transmits a page information holding request message in accordance with the DHT routing table. The node that has received the page information holding request message transmitted by the second management node becomes a new first management node. As a result, a new first management node is determined in place of the withdrawn first management node. Then, the second management node transmits a page information holding request message to the newly determined first management node. In this way, the content distributed storage system is constructed so that the first management node and the second management node always exist on the network.

  Next, the page information update process will be described with reference to FIG. FIG. 5 is an explanatory diagram illustrating the page update process in the present embodiment. As shown in FIG. 5, the center server SA performs a page information update process on the above-described tree-structured catalog information (FIG. 5: (1)). In the page information update process, page information including the updated record is newly generated. In order to update the record to the tree-structured catalog information, a new page number is assigned to the generated page information. The same index is assigned to the page information before update and the page information after update. The page information of this embodiment is given a new page number every time a record is updated.

  Then, a new management node that manages the updated page information is determined by the center server SA (FIG. 5: (2)). Since at least one node device storing the updated page information exists on the network, the management node is determined in this embodiment. In the present embodiment, the center server SA determines a hash value using a page number newly given to the updated page information and an index that is not different from that before the update. The hash function used at this time may be an arbitrary hash function, but all nodes need to continue to use one hash function for determining the first management node and one hash function for determining the second management node. There is. The hash function for determining the first management node and the hash function for determining the second management node may be the same function. In the example shown in FIG. 5, a new management node N37 is determined as a new first management node based on the hash value generated using the newly assigned page number. In the example illustrated in FIG. 5, the management node N24 is determined as the second management node based on the hash value generated using the updated index. The same management node 24 is determined before and after the page information is updated. Thus, the added page information is stored by the new first management node and second management node.

  Then, the center server SA transmits a page information holding request message to the determined new first management node (N37) and second management node (N24) (FIG. 5: (3)). The page information holding request message includes updated page information and updated route point information. When the page information holding request message is received, the new first management node and the second management node perform a falsification check of the page information included in the received message. If no falsification has been performed, the new first management node stores the page information included in the page information holding request message and the route point information (FIG. 5: (4)).

  Further, when the second management node receives the page information holding request message, the page information included in the received message is checked for tampering. If tampering has not been performed, the second management node updates the stored page information and route point information to the page information and route point information included in the page information holding request message (FIG. 5: (5)).

  When the page information storage request message is received from the old first management node (FIG. 5: (6)), the second management node transmits a page information deletion request message (FIG. 5: (7)). In the example of FIG. 5, the second management node device transmits a page information deletion request message to the first management node (N15) before update based on the hash value of the page information before update. The page information deletion request message includes information indicating page information before update.

  When the first node device before update receives the page information deletion request message, the page information before update is deleted from the first management list storage area 251 based on the received page information deletion request message (FIG. 5). : (8)). The page information before update is deleted from the first management list storage area 251 of the storage unit provided in the first node device before update. Instead of deleting the page information before the update, the page information before the update may be restricted so as not to be referenced from other nodes.

  As described with reference to FIGS. 3 to 5, the first management node and the second management node store the added page information or updated page information in order to securely store the added page information or updated page information. It is possible to prevent the page information from being deleted from the node device on the network and lost. Thereby, the center server SA can generate a backup of the catalog information of the tree structure by using the page information that is surely stored in the node device even if the RAID is not set. Thereby, the center server SA transmits a page information request message to the first management node or the second management node. Note that the center server SA may transmit a page information request message to the node device connected to the overlay network using, for example, multicast. The page information request message is a message that causes the node device including the first management node and the second management node to transmit page information to the center server SA. By transmitting the page information request message to the node device, the center server SA can generate a backup of the catalog information. Note that the page information request message of this embodiment is an example of a storage request message and a confirmation message of the present invention.

[Electrical configuration of node equipment]
Next, an electrical configuration of the node device will be described with reference to FIG. FIG. 6 is a block diagram illustrating an electrical configuration of the node device according to the present embodiment. As shown in FIG. 6, the node device according to the present embodiment includes a CPU 1 that controls the node device. An HDD 2, a RAM 3, a decoder unit 4, and a communication unit 9 are electrically connected to the CPU 1. The storage means such as the HDD 2 and the RAM 3 and the CPU 1 constitute a computer of the node device. The CPU 1, HDD 2, RAM 3, decoder unit 4, and communication unit 9 are connected to each other via a bus. As the node device, a personal computer, an STB (Set Top Box) or the like can be applied.

  The HDD 2 includes a program storage area 21, a routing table storage area 23, a distributed page information storage area 24, and a management page information storage area 25. The program storage area 21 includes a main operation processing program storage area 22. The main operation processing program storage area 22 stores a main operation processing program. The main operation processing program is a program that causes the node device to execute main operation processing.

  The routing table storage area 23 stores the DHT routing table of the present embodiment. The distributed page information storage area 24 stores page information distributed to each node device in the present embodiment. The management page information storage area 25 of this embodiment is an example of the second storage unit of the present invention.

  The management page information storage area 25 stores page information that the node device stores as the first management node or the second management node separately from the distributed page information storage area 24. The management page information storage area 25 includes a first management list storage area 251 and a second management list storage area 252.

  The first management list storage area 251 stores page information stored as the first management node. The second management list storage area 252 stores page information stored as the second management node. The management page information storage area 25 of this embodiment is an example of the second storage unit of the present invention.

  Note that the main operation processing program of the node device may be downloaded from a predetermined server on the network NW, for example, or may be recorded on a recording medium such as a CD-ROM via a drive of the recording medium. May be read.

  The RAM 3 includes a content data temporary storage area 31. The content data temporary storage area 31 temporarily stores content data transmitted and received by the overlay network OL. The communication unit 9 controls communication of information with a node device or an external device through the network NW.

  The node device performs reception processing for receiving the content, chunk, or meta information file transmitted in response to the request via the communication unit 9. The content, chunk, or meta information file of the present embodiment is packetized and transmitted. Each packet is received through the communication unit 9 and temporarily stored in the RAM 3. The content temporarily stored in this manner is read from the RAM 3 and reproduced and output through the decoder unit 4, the video processing unit 5, the audio processing unit 7, the display 6, and the speaker 8. Alternatively, the content stored in the RAM 3 may be read from the RAM 3 and stored in the HDD 2. Alternatively, the content data may be stored directly in the HDD 2 without going through the RAM 3. Thereafter, the content is read from the HDD 2 in accordance with an operation instruction from the user. The read content is reproduced and output through the decoder unit 4, the video processing unit 5, the audio processing unit 7, the display 6, and the speaker 8. Thereby, the user can view the content.

[Electrical configuration of center server SA]
Next, the electrical configuration of the center server SA will be described with reference to FIG. FIG. 7 is a block diagram showing an electrical configuration of the center server SA of the present embodiment. As shown in FIG. 7, the center server SA of this embodiment includes a CPU 11 that controls the center server SA. The CPU 11 is electrically connected to the HDD 12, the RAM 13, and the communication unit 19. The storage means such as the HDD 12 and the RAM 13 and the CPU 11 constitute a computer of the center server SA. The CPU 11, HDD 12, RAM 13, and communication unit 19 are connected to each other via a bus.

  The HDD 12 includes a program storage area 121, a catalog information storage area 123, and a content data storage area 124. The program storage area 121 includes a main operation processing program storage area 122. The main operation processing program storage area 122 stores the main operation processing program of the center server SA. The main operation processing program of the center server SA is a program that causes the center server SA to execute main operation processing.

  The catalog information storage area 123 stores the tree-structured catalog information of this embodiment. The content data storage area 124 stores the original of the content released to the overlay network OL. The catalog information storage area 123 of this embodiment is an example of a first storage unit of the present invention.

  The main operation processing program of the center server SA may be downloaded from a predetermined server on the network NW, for example, or may be recorded on a recording medium such as a CD-ROM and a drive of the recording medium may be used. You may make it read via.

  The communication unit 19 controls communication of information with a node device or an external device through the network NW.

[Main operation of center server SA]
The operation and action of the center server SA of this embodiment will be described below with reference to FIG. FIG. 8 is a flowchart showing a processing procedure of the main operation in the center server SA. The main operation of the center server SA is performed by connecting an external power source such as a commercial power source and the node device via a power source or an outlet. The processing shown below is processed by the CPU 11.

  In step S101, it is determined whether or not the power is turned off. When it is determined that the center server SA is powered off (step S101: YES), the main operation of the center server SA is terminated. If it is not determined that the power of the center server SA is turned off (step S101: NO), step S102 is executed.

  In step S102, it is determined whether or not the timing for determining whether or not the page information in the catalog information has been damaged has arrived. The center server SA of the present embodiment periodically checks whether page information in the catalog information is damaged. A timer operation (not shown) provided in the CPU 11 performs a time measuring operation. It is determined whether or not the time counted by the CPU 11 has reached a predetermined time for determining breakage. If it is determined that the timing has arrived (step S102: YES), step S103 is executed. If it is not determined that the timing has arrived (step S102: NO), step S101 is executed again.

  In step S103, it is determined whether or not the page information in the catalog information has been damaged. Specifically, it is determined whether or not there is page information that cannot be read in the catalog information stored in the catalog information storage area 123. If it is determined that there is page information that cannot be read, it is determined that the page information is damaged. On the other hand, when all the page information can be read, it is determined that the page information is not damaged. If it is determined that the page information is damaged (step S103: YES), step S104 is executed. If it is not determined that the page information is damaged (step S103: NO), step S107 is executed. The computer of the center server SA and step S103 of this embodiment are an example of the first determination unit of the present invention. Moreover, step S103 of the present embodiment is an example of a first determination step of the present invention.

  In step S104, a page information request message is transmitted to the first management node and the second management node of the damaged page information. The page information request message is a message including the page number and index of damaged page information. Note that the page information request message may be transmitted only to either the first management node or the second management node of the damaged page information. The computer of the center server SA and step S104 of this embodiment are an example of the first transmission means of the present invention. Moreover, step S104 of this embodiment is an example of the first transmission step of the present invention.

  In step S105, it is determined whether the page information requested in step S104 has been received. If it is determined that the page information requested in step S104 has been received (step S105: YES), step S106 is executed. If it is not determined that the page information requested in step S104 has been received (step S105: NO), step S105 is repeatedly executed. The computer of the center server SA and step S105 of this embodiment are an example of the first receiving means of the present invention. Moreover, step S105 of this embodiment is an example of the first reception step of the present invention.

  In step S106, the page information determined to be damaged in step S103 is replaced using the page information received in step S105. Thereby, even if the catalog information stored in the center server SA is damaged, it can be repaired without using a RAID. Thereafter, step S101 is executed again. The computer of the center server SA and step S106 of this embodiment are an example of the updating unit of the present invention. Moreover, step S106 of this embodiment is an example of the update step of this invention.

  In step S107, it is determined whether page information has been added to the catalog information. If it is determined that page information has been added (step S107: YES), step S108 is executed. If it is not determined that page information has been added (step S107: NO), step S111 is executed.

  In step S108, a page number and an index are added to the added page information. Then, the page information to which the page number and the index are assigned is added to the catalog information. The added catalog information is stored in the catalog information storage area 123.

  In step S109, the first management node and the second management node are determined based on the page number and index assigned in step S108. The computer of the center server SA and step S109 of this embodiment are an example of the first determination unit of the present invention.

  In step S110, a page information holding request message is transmitted to the determined first management node and second management node. The computer of the center server SA and step S110 of this embodiment are an example of the first transmission means of the present invention.

  In step S111, it is determined whether or not the page information included in the catalog information has been updated. If it is determined that the page information has been updated (step S111: YES), step S112 is executed. If it is not determined that the page information has been updated (step S111: NO), step S101 is executed.

  In step S112, a new page number is given to the updated page information. Then, the page information newly assigned with the page number is added to the catalog information. In this case, the same index is used before and after the page information is updated. The updated catalog information is stored in the catalog information storage area 123.

  In step S113, a new first management node is determined based on the page number assigned in step S112.

  In step S114, a page information retention request message is transmitted toward the determined first management node.

[Main operation of node device]
The operation and action of the node device according to this embodiment will be described below with reference to FIGS. First, operation | movement and an effect | action of a node apparatus are demonstrated with reference to an accompanying drawing. FIG. 9 is a flowchart illustrating a processing procedure of the main operation in the node device. The main operation of the node device is performed by connecting an external power source such as a commercial power source and the node device via a power source or an outlet. The processing shown below is processed by the CPU 1.

  In step S201, it is determined whether or not the power is turned off. When it is determined that the power of the node device has been turned off (step S201: YES), the main operation of the node device is terminated. If it is not determined that the node device is powered off (step S201: NO), step S202 is executed.

  In step S202, it is determined whether a page information holding request message has been received. If it is determined that the page information holding request message has been received (step S202: YES), step S203 is executed. If it is not determined that the page information holding request message has been received (step S202: NO), step S204 is executed. The computer of this embodiment and step S202 are an example of the third receiving means of the present invention.

  In step S203, a page information holding process is executed. Details of the page information holding process will be described later.

  In step S204, it is determined whether a page information deletion request message has been received. If it is determined that the page information deletion request message has been received (step S204: YES), step S205 is executed. If it is not determined that the page information deletion request message has been received (step S204: NO), step S206 is executed.

  In step S205, page information deletion processing is executed. Details of the page information deletion process will be described later.

  In step S206, it is determined whether a page information request message has been received. If it is determined that the page information request message has been received (step S206: YES), step S207 is executed. If it is not determined that the page information request message has been received (step S206: NO), step S209 is executed. The computer of the node device of this embodiment and step S206 are an example of the second receiving means of the present invention. Moreover, step S206 of the present embodiment is an example of a second reception step of the present invention.

  In step S207, it is determined whether or not the page information requested in step S206 is stored in the first management list storage area 251 or the second management list storage area 252. In step S207, it is determined whether or not the page information requested in step S206 is stored in the first management list storage area 251, the second management list storage area 252, or the distributed page information storage area 24. good. When it is determined that the page information requested in step S206 is stored (step S207: YES), step S208 is executed. If it is not determined that the page information requested in step S206 is stored (step S207: NO), step S201 is executed.

  In step S208, the page information requested in step S206 is transmitted to the center server SA. Specifically, the page information stored in the first management list storage area 251 or the second management list storage area 252 is transmitted to the center server SA. The page information stored in the first management list storage area 251, the second management list storage area 252, or the distributed page information storage area 24 is transmitted to the center server SA. The computer of the node device of this embodiment and step S208 are an example of the second transmission means of the present invention. Moreover, step S208 of this embodiment is an example of the second transmission step of the present invention.

  In step S209, based on the first management list stored in the first management list storage area 251, page information for which a predetermined time or more has passed since the page information holding request message was transmitted to the second management node last time. It is determined whether or not it exists. Specifically, time information indicating the current time is counted by the time counting operation of the CPU 1. Then, it is determined whether there is page information in which the difference between the current time and the time when the previous message was transmitted is greater than or equal to a predetermined value. If it is determined that there is page information for which a predetermined time has elapsed since the previous transmission of the page information holding request message to the second management node (step S209: YES), step S210 is executed. If it is not determined that there is page information for which a predetermined time or more has elapsed since the previous transmission of the page information holding request message to the second management node (step S209: NO), step S211 is executed.

  In step S210, a page information holding request message is transmitted to the second management node of the page information determined to have passed the predetermined time in step S209. Note that time information indicating the transmission time at which the page information holding request message is transmitted in step S210 is stored in the first management list storage area 251 in association with the page information. The computer of this embodiment and step S210 are an example of the 3rd transmission means of this invention.

  In step S211, based on the second management list stored in the second management list storage area 252, whether or not a predetermined time or more has elapsed since the previous page information holding request message was received from the first management node. Whether or not exists is determined. Specifically, time information indicating the current time is counted by the time counting operation of the CPU 1. Then, it is determined whether there is page information in which the difference between the current time and the time when the previous message was received is greater than or equal to a predetermined value. If it is determined that there is page information for which a predetermined time has elapsed since the previous reception of the page information holding request message from the first management node (step S211: YES), step S212 is executed. If it is not determined that there is page information for which a predetermined time or more has elapsed since the previous reception of the page information holding request message from the first management node (step S211: NO), step S201 is executed. The computer of this embodiment and step S211 are examples of the second determination unit of the present invention.

  In step S212, a new first management node of the page information determined to have passed the predetermined time in step S211 is determined. Specifically, the hash value is determined based on the page number. The computer of this embodiment and step S212 are examples of the second determination unit of the present invention.

  In step S213, a page information holding request message is transmitted to the new first management node. Specifically, the page information holding request message is transmitted according to the hash value determined in step S212 and the DHT routing table.

[Page information retention processing]
The operation and action of the page information holding process of this embodiment will be described with reference to FIG. FIG. 10 is a flowchart showing the processing procedure of the page information holding processing of this embodiment. In step S301, it is determined whether or not the page information holding request message received in step S202 is a message addressed to the second management node. If it is determined that the message is addressed to the second management node (step 301: YES), step S302 is executed. If it is not determined that the message is addressed to the second management node (step 301: NO), step S308 is executed.

  In step S302, it is determined whether or not the page information included in the page information holding request message received in step S202 is already stored in the second management list storage area 252. If it is determined that the second management list storage area 252 has already been stored (step S302: YES), step S304 is executed. If it is not determined that the second management list storage area 252 has already been stored (step S302: NO), step S303 is executed.

  In step S303, the page information included in the page information holding request message received in step S202 is stored in the second management list storage area 252.

  In step S304, it is determined whether or not the page information included in the page information holding request message received in step S202 is newer than the page information stored in the second management list storage area 252. The page number of the page information stored in the second management list storage area 252 is compared with the page number of the page information received in step S202. If the page number value of the page information received in step S202 is larger, it is determined that it is a new page number. When it is determined that the page number of the page information received in step S202 is a new page number (step S304: YES), step S305 is executed. When it is determined that the page number of the page information received in step S202 is a new page number (step S304: NO), step S307 is executed.

  In step S305, the page information stored in the second management list storage area 252 is overwritten with the page information included in the page information holding request message received in step S202.

  In step S306, a page deletion request message is transmitted to the first management node of the page information before being overwritten in step S305.

  In step S307, the page information deletion request message is transmitted to the first management node that is the transmission source of the page information holding request message received in step S202.

  In step S308, it is determined whether or not the page information holding request message received in step S202 is a message addressed to the first management node. If it is determined that the message is addressed to the first management node (step 308: YES), step S309 is executed. If it is not determined that the message is addressed to the second management node (step 308: NO), the page information holding process is terminated.

  In step S309, it is determined whether or not the page information included in the page information holding request message received in step S202 is already stored in the first management list storage area 251. If it is determined that the information is already stored in the first management list storage area 251 (step S309: YES), step S311 is executed. If it is not determined that the information is already stored in the first management list storage area 251 (step S309: NO), step S310 is executed.

  In step S310, the page information included in the page information holding request message received in step S202 is stored in the first management list storage area 251.

  In step S311, time information indicating the time when the page information holding request message is received in step S202 is stored in the first management list information storage area 251. The page information indicated by the page information holding request message and the time information when the page information holding request message is received are associated with each other and stored in the first management list information storage area 251. If page information has already been stored in the first management list information storage area 251, the time information stored in association with the page information indicates the time at which the page information holding request message was received in step S202. Updated to time information.

  In step S312, time information indicating the time when the page information holding request message is received in step S202 is stored in the second management list information storage area 252. The page information indicated by the page information holding request message and the time information when the page information holding request message is received are associated with each other and stored in the second management list information storage area 252. If page information has already been stored in the second management list information storage area 252, the time information stored in association with the page information indicates the time at which the page information holding request message was received in step S202. Updated to time information.

[Page information retention processing]
The operation and action of the page information deletion process of this embodiment will be described with reference to FIG. FIG. 11 is a flowchart showing a processing procedure of page information deletion processing according to the present embodiment. In step S401, it is determined whether or not the page information included in the page information deletion request message received in step S204 is stored in the first management node storage area 251. If it is determined that it is stored in the first management node storage area 251 (step S401: YES), step S402 is executed. If it is not determined that the information is stored in the first management node storage area 251 (step S401: NO), the page information deletion process is terminated.

  In step S402, the page information included in the page information deletion request message received in step S204 is deleted from the first management node storage area 251. Instead of deleting the page information from the first management node storage area 251, the page information to be deleted may be set so that the reference from other node devices is restricted.

  In this embodiment, the peer-to-peer communication system using the DHT routing table is applied to the overlay network OL. However, the present invention is not limited to this. The present invention may be applied to other peer-to-peer communication systems or systems using overlay networks. For example, the present invention may be applied to a communication system using a routing table other than DHT or a peer-to-peer communication system. An example of a peer-to-peer communication system that does not use DHT is a hybrid peer-to-peer communication system. The present invention may be applied to a hybrid peer-to-peer communication system or a pure peer-to-peer communication system. Further, the present invention may be applied to an information communication system that does not use an overlay network. For example, the present invention may be applied to a system in which content is distributed and stored by a plurality of server devices.

  In the present embodiment, both the first management node and the second management node are determined, but either the first management node or the second management node may be determined. A plurality of first management nodes and a plurality of second management nodes may be determined based on the page number and identification information of the page information. In this case, a plurality of first management nodes and a plurality of second management nodes are determined by using a plurality of types of hash functions.

  Further, in the periodic confirmation process of the present embodiment, the page information holding request message is transmitted from the first management node to the second management node. However, the page information holding message is transmitted from the second management node to the first management node. An information holding request message may be transmitted. In addition, the first management node and the second management node may periodically transmit a page information holding request message to each other. In this case, the process of the second management node shown in FIGS. 9 to 11 is also executed on the first management node. Similarly, the processing of the first management node shown in FIGS. 9 to 11 is also executed on the second management node.

  In the present embodiment, the first management node is determined based on the page number, and the second management node is determined based on the identification information. The second management node may be determined based on the page number, and the first management node may be determined based on the identification information. Further, the page information holding request message may be transmitted from the center server SA to an arbitrary node device connected to the overlay network OL.

1 CPU
2 HDD
3 RAM
4 Decoder unit 5 Video processing unit 6 Display 7 Audio processing unit 8 Speaker 9 Communication unit 11 CPU
12 HDD
13 RAM
DESCRIPTION OF SYMBOLS 19 Communication part 21 Program storage area 22 Main operation processing program storage area 23 Routing table storage area 24 Distributed page information storage area 25 Management page information storage area 26 Index information storage area 31 Temporary content storage area 121 Program storage area 122 Main operation processing program Storage area 123 Catalog information storage area 124 Content data storage area 251 First management list storage area 252 Second management list storage area Nn Node device NW Network OL Overlay network P Communication line S Content distributed storage system SA Center server

Claims (2)

In an information communication system in which a plurality of search information for searching for data stored in a distributed manner in a network is distributed and stored in a plurality of node devices connected to the network.
The information communication system comprising an information processing device for storing a plurality of search information distributed and stored in the plurality of node devices,
The information processing apparatus includes:
First storage means for storing a plurality of search information distributed and stored in the plurality of node devices;
First determination means for determining whether there is damaged search information among the plurality of search information stored in the first storage means;
First transmission means for transmitting a transmission request for damaged search information to at least one of the plurality of node devices when it is determined by the first determination means that there is damaged search information;
First receiving means for receiving damaged search information from any of the plurality of node devices;
Update means for updating search information damaged in the search information stored in the first storage means using the search information received by the first receiving means;
With
The node device is
Second receiving means for receiving the transmission request;
Second transmission means for transmitting the search information stored in the node device to the information processing apparatus based on the transmission request received by the second reception means;
Equipped with a,
The first storage means stores the search information including order information indicating an order in which the search information is added and identification information for identifying the search information,
The information processing apparatus includes:
Based on the order information, the first management node that stores the search information corresponding to the order information from the plurality of node devices, or the plurality of node devices based on the identification information. First determination means for determining any one of the second management nodes storing the search information corresponding to the identification information;
The first transmission means transmits a save request message for saving the search information corresponding to the order information or the identification information to the first management node or the second management node determined by the first determination means. And
The node device is
Second storage means for storing the search information indicated by the save request message;
The first determining means determines the first management node and the second management node;
The first transmission unit transmits a save request message for saving the search information corresponding to the order information or the identification information toward the first management node and the second management node determined by the first determination unit. And
The node device is
Second storage means for storing the search information indicated by the save request message;
Either one of the first management node or the second management node of the plurality of node devices transmits a confirmation message for periodically confirming the existence to the other node device. Means,
Third receiving means for receiving the confirmation message;
Second determination means for determining whether or not the confirmation message has not been received by the third reception means for a predetermined time or more;
When the confirmation message is not received for a predetermined time or more by the second determination means, based on either the order information or the identification information included in the search information stored in the second storage means, A second determination means for determining a new first management node or the second management node;
The second transmission means sends a save request message for saving the search information stored in the second storage means to the new first management node or the second management node determined by the second determination means. An information communication system characterized by transmitting .
In an information communication system in which a plurality of search information for searching for data stored in a distributed manner in a network is distributed and stored in a plurality of node devices connected to the network.
An information communication method comprising an information processing device for storing a plurality of search information distributed and stored in the plurality of node devices,
The information processing apparatus determines whether there is damaged search information among the plurality of search information stored in the first storage unit that stores the plurality of search information distributed and stored in the plurality of node devices. A determination step to:
A first transmission step in which, when it is determined that there is damaged search information in the determination step, the information processing apparatus transmits a transmission request for the damaged search information to at least one of the plurality of node devices; ,
A second receiving step in which the node device receives the transmission request;
A second transmission step in which the node device transmits the search information stored in the node device to the information processing device based on the transmission request received in the second reception step;
A first receiving step in which the information processing device receives damaged search information from any of the plurality of node devices;
An update step of updating search information damaged in the search information stored in the first storage means using the search information received by the first reception step;
Only including,
The first storage means stores the search information including order information indicating an order in which the search information is added and identification information for identifying the search information,
The information communication method further includes:
Based on the order information, the first management node that stores the search information corresponding to the order information from among the plurality of node devices, and the identification from among the plurality of node devices based on the identification information A first determination step in which the information processing apparatus determines a second management node that stores the search information corresponding to the information;
The information processing apparatus transmits a storage request message for storing the search information corresponding to the order information or the identification information toward the first management node and the second management node determined in the first determination step. A third transmission step;
A fourth transmission in which either one of the first management node or the second management node among the plurality of node devices periodically transmits a confirmation message confirming the existence to the other node device. Steps,
A third receiving step in which the node device receives the confirmation message;
A second determination step in which the node device determines whether or not the confirmation message has not been received for a predetermined time or more in the third reception step;
When the confirmation message is not received for a predetermined time or more by the second determination step, the second storage means included in the node device, the second storage storing the search information indicated by the save request message A second determination step in which the node device determines a new first management node or second management node based on either the order information or the identification information included in the search information stored in a means; ,
The node device transmits a save request message for saving the search information stored in the second storage means to the new first management node or the second management node determined in the second determination step. A fifth transmission step;
An information communication method including: