JPWO2009107184A1 - Replica processing method, program and apparatus - Google Patents

Abstract

Even if you cannot always connect, synchronize DBs between sites. The replication processing method receives a DB update instruction from a user, updates the DB according to the update instruction, and stores at least an update address indicating an area to be updated and updated data in a first address table; Connecting to other sites at the timing, obtaining a second address table storing update addresses and updated data relating to updates at other sites, and terminating the connection with other sites; the first address table and When the same update address is stored in the second address table, either the updated data corresponding to the update address and stored in the first address table or the second address table according to a predetermined rule is the update address. Specified as the data to be reflected in the corresponding area in the DB and the updated data stored in the second address table as the data to be reflected are identified And updating the relevant area in the DB with the updated data.

Description

  The present invention relates to a technique for synchronizing a database between bases using a narrowband line.

  Conventionally, for example, in a backup system, there is a technique for creating a replica of a database and synchronizing the main body and the replica.

  For example, Japanese Patent Laid-Open No. 2000-035911 discloses a technique for equalizing a database held by the own server and a database held by another server in a distributed system including a plurality of servers. Specifically, when the other server is disconnected from the distributed system and reconnected while the databases of the local server and the other server are equivalent, the local server is disconnected from the other server until it is reconnected. Data changed in the server database is sent to other servers.

  Further, for example, Japanese Patent Application Laid-Open No. 11-259324 discloses a duplex control device that can reduce the reduction in reliability during the copying period of the stored contents of the main storage device and the compression of processing capacity as much as possible. Specifically, the duplex control device is provided for the function test of each channel control device, and the stored contents of the main memory device of the active system are transferred to the pseudo input / output device having the direct memory access (DMA) function. The memory copy command receiving means for receiving and identifying the memory copy command for requesting copying to the main storage device of the system, and the memory copy command receiving means when the memory copy command receiving means receives the memory copy command from the active central controller. The unit data stored in each address of the main storage device is sequentially extracted, and the data copying operation to store in the same address of the other main storage device is continuously executed for all the storage areas of the main storage device And a memory copy operation control means for notifying the active central controller of completion of execution of the memory copy operation.

  Further, for example, in Japanese Patent Application Laid-Open No. 2007-233543, the database synchronization processing is realized in a realistic time while the network between the primary site and the secondary site is constructed with a narrow bandwidth line, and the operation cost of the system is suppressed. A database management system that can do this is disclosed. Specifically, the database management system includes a storage device that stores a database, and a database management server that receives a database reference request or update request and refers to or updates the database of the storage device. An update execution unit that reads the database of the storage device based on the update request and updates the data, and an unnecessary information removal unit that continuously overwrites unused areas in the updated data with preset characters or values; And a writing unit for writing data to the storage device. In addition, the storage device includes a remote copy unit that is connected to a second storage device that stores a copy of the database via the network and transfers the database to the second storage device. When the database of the storage device is transferred via the network device, the network device is configured to transfer the database by compressing continuous values.

  However, the techniques described in these publications are all related to data backup, and no consideration is given to the case where each of a plurality of databases is updated.

In addition, when a database is installed at each base and each database is updated, for example, when a base is constantly connected using a broadband line and the database at a certain base is updated, Conventionally, there is a technology for synchronizing between bases by controlling the database exclusively.
JP 2000-035911 A JP 11-259324 A JP 2007-233543 A

  However, there are areas where the always-on service cannot be used (for example, areas away from the telephone office), and there are cases where the above-described conventional technology cannot be employed. Further, in order to use the always-on service in such an area, it is necessary to introduce a dedicated line, for example, and costs such as capital investment and communication charges are required.

  Accordingly, an object of the present invention is to provide a system in which a database is installed at each site and each database is updated. Is to provide technology for database synchronization.

  Another object of the present invention is to provide a technique for preventing omission of database update.

  The replication processing method according to the present invention is a replication processing method in the case of performing communication between bases using a narrowband line. When a database update instruction is received from a user, the database is updated according to the update instruction. A first update step of storing at least an update address indicating an area to be updated and updated data in the first update address table; and connecting to another base at a predetermined timing to update at another base The second update address table storing the update address and the updated data is acquired, the acquisition step of ending the connection with another base, the first update address table, and the second update address table When the same update address is stored, the first update address corresponding to the update address and corresponding to the first update address is determined according to a predetermined rule. Specifying any of the updated data stored in the stable table and the second update address table as data to be reflected in the corresponding area in the database indicated by the update address, and the data to be reflected When the data after update stored in the second update address table is specified, a second update step of updating the corresponding area in the database with the data after update is included.

  In this way, even if the base is located in an area where the always-on service cannot be used, the database between the bases is synchronized using a narrowband line such as an ISDN (Integrated Services Digital Network) line. Will be able to. In addition, for example, in the case of a pay-as-you-go system, communication costs can be minimized.

  Further, when the corresponding area in the database is updated by the second update step, a step of notifying the user who has instructed to update the corresponding area in the database of discarding the update data may be further included.

  In this way, when the same location is updated in the local site and the other site, and the data of the other site is reflected in the database, the user is notified, so the user can update again. , Can prevent omission of update.

  In addition, a predetermined rule gives priority to a base with a large number of updates, a rule to give priority to a base with a large number of updates, a rule to give priority to a base with a late update date, a rule to give priority to a base with a small update address difference, Or it may be a rule which gives priority to a base with high priority set up beforehand.

  For example, by performing processing according to a rule that prioritizes a base with a large number of updates or a rule that prioritizes a base with a large number of updates, data at a base with a high update frequency can be prioritized. In addition, by processing according to the rule that prioritizes the base with the latest update date and time, data close to the current state can be reflected in the database. For example, if the measurement data is stored in the database, the last updated data is closest to the current state. Furthermore, by processing according to a rule that gives priority to a base having a small difference in update address, it becomes possible to reflect an update over a plurality of areas in the database as a series of updates. For example, the smaller the difference between the update addresses, the higher the possibility of updating continuously, and it is better to reflect it in the database as a series of updates. In addition, by performing processing according to a rule that prioritizes a high priority base set in advance, for example, data of the head office can be prioritized.

  In some cases, the steps after the acquisition step are executed according to a preset schedule. Further, the narrowband line may be a metered line. For example, a schedule that shortens the execution interval when the update frequency is high and sets the execution interval high when the update frequency is low may be set according to the operation status of the system.

  Note that a program for causing a computer to execute the replication processing method according to the present invention can be created, and the program is, for example, a storage medium such as a flexible disk, a CD-ROM, a magneto-optical disk, a semiconductor memory, a hard disk, or the like. It is stored in a storage device. In some cases, digital signals are distributed over a network. Note that data being processed is temporarily stored in a storage device such as a computer memory.

  According to the present invention, in a system in which a database is installed for each base and each database is updated, even when the base is located in an area where the always-on service cannot be used, the database between the bases is suppressed while reducing costs. Will be able to synchronize.

  According to another aspect of the present invention, it is possible to prevent omission of database update.

FIG. 1 is a system outline diagram according to the embodiment of the present invention. FIG. 2 is a diagram illustrating an example of data stored in the user information storage unit. FIG. 3 is a diagram illustrating an example of the update address table. FIG. 4 is a diagram showing a processing flow when registering data necessary for processing. FIG. 5 is a diagram showing a processing flow when the database is updated. FIG. 6 is a diagram for explaining a processing mode in the present embodiment. FIG. 7 is a diagram for explaining the processing mode (mode 1). FIG. 8 is a diagram for explaining the processing mode (mode 2). FIG. 9 is a diagram for explaining the processing mode (mode 3). FIG. 10 is a diagram for explaining the processing mode (mode 4). FIG. 11 is a diagram for explaining the processing mode (mode 5). FIG. 12 is a diagram illustrating a processing flow of the replication process. FIG. 13 is a diagram showing a first part of the processing flow of the same address update processing. FIG. 14 is a diagram showing a second part of the processing flow of the same address update processing. FIG. 15 is a functional block diagram of a computer.

  FIG. 1 shows an outline of a system according to an embodiment of the present invention. In the example of FIG. 1, the base A, the base B, and the base C are connected to the public line network 1 by a narrow band line such as an ISDN line. In this case, at least one of the base A, the base B, and the base C is located in an area far away from the telephone station and, for example, ADSL (Asymmetric Digital Subscriber Line) or the like cannot be always connected, or for economic reasons. It is assumed that the continuous connection cannot be selected.

  In addition, the base A has a management device 3 connected to the ISDN line, a database 5 for storing data to be synchronized, and user information for storing user information (for example, user ID, user name, and mail address). A storage unit 7, a replication information storage unit 9 for storing information (for example, schedule and processing mode) relating to a replication process for synchronizing the database 5 with another base, and an update address table for storing an update address table to be described later And a storage unit 11. The database 5, the user information storage unit 7, the replication information storage unit 9 and the update address table storage unit 11 are managed by the management device 3.

  The management device 3 includes an input unit 31 that receives an input of a data update instruction or user information from a user, a communication unit 33 that exchanges data with other bases via the public line network 1, a replication information storage unit 9, and A replication control unit 35 that performs a replication process based on the data stored in the update address table storage unit 11; Furthermore, the replication control unit 35 refers to the schedule stored in the replication information storage unit 9 and determines whether or not the execution time of the replication process has been reached, and an update address table that acquires an update address table of another base Based on the acquisition unit 352, the update address table stored in the update address table storage unit 11 and the update address table of other bases, the aggregation processing unit 353 that counts the number of updates, and the like, stored in the replication information storage unit 9 Based on the processing mode and the totaling result of the totaling processing unit 353, the determination unit 354 that determines the priority base, the DB update processing unit 355 that updates the database 5 in accordance with the data update instruction from the user, and the user information storage unit 7 An update discard notification unit 356 that transmits an update discard notification based on the stored mail address.

  Although not shown in the example of FIG. 1, the base B and the base C have the same configuration as the base A. Further, although FIG. 1 shows three examples of the base A, the base B, and the base C, the number of bases is not limited to three. Hereinafter, the case where the number of bases is two will be basically described.

  FIG. 2 shows an example of data stored in the user information storage unit 7. In the example of FIG. 2, the user information storage unit 7 includes a user ID column, a user name column, and a mail address column.

  FIG. 3 shows an example of an update address table stored in the update address table storage unit. In the example of FIG. 3, the update address table includes an update address column, an operation content column, an old data column, and a new data column. An address indicating an update target area is set in the update address column. In addition, data before update is set in the old data column, and data after update is set in the new data column. Note that “-” in the column of new data indicates that the data in the area has been deleted.

  Next, processing of the system shown in FIG. 1 will be described with reference to FIGS. First, a process when registering data necessary for the process will be described with reference to FIG. For example, the user operates a keyboard and a mouse on a user registration screen (not shown) displayed on the display device of the management device 3 to input a user name and an email address. And the input part 31 of the management apparatus 3 receives the input of a user name and an e-mail address, and registers it in the user information storage part 7 (FIG. 4: step S1). At this time, the management apparatus 3 assigns a user ID according to a predetermined rule, and registers it in the user information storage unit 7 in association with the user name and mail address. If the user has already been registered, this step is skipped.

  Further, the user operates a keyboard and a mouse on a schedule setting screen (not shown) displayed on the display device of the management device 3 to input a replication processing schedule (for example, a processing interval). In addition, regarding the schedule of the replication process, it is assumed that an agreement has been obtained between the bases in advance. Then, the input unit 31 receives an input of a schedule for the replication process and registers it in the replication information storage unit 9 (step S3). If the replication processing schedule has already been set and there is no change, this step is skipped.

  Furthermore, the user operates a keyboard or mouse on a processing mode selection screen (not shown) displayed on the display device of the management device 3 to select one of the processing modes prepared in advance. Details of the processing mode will be described below. Also, it is assumed that an agreement has been made between the bases in advance regarding which processing mode is selected. And the input part 31 receives the selection input of a processing mode, and stores it in the replication information storage part 9 (step S5). That is, the same setting is made for the schedule and processing mode of the replication process at each site. In steps S1 to S5, the user may perform input and selection by operating a user terminal connected to the management apparatus 3. In this case, user information, a schedule, a processing mode, and the like are transmitted from the user terminal to the management apparatus 3.

  Next, a process for updating the database 5 will be described with reference to FIG. First, on the DB editing screen (not shown) displayed on the display device of the management device 3, the user operates the keyboard and mouse to instruct data update of the database 5. Note that it is assumed that login or the like has already been completed and the management device 3 holds data such as a user ID. And the input part 31 of the management apparatus 3 receives a data update instruction | indication, and once stores it in a memory | storage device (FIG. 5: step S11). And the input part 31 updates the database 5 according to the data update instruction | indication stored in the memory | storage device (step S13). At this time, the input unit 31 temporarily stores the data before update in the storage device. In addition, the input unit 31 generates a record including an address indicating an update target area, data before update, data after update, a user ID of a user who instructs the update, and an update date and time. It adds to the address table storage part 11 (step S15). The current date is set as the update date. In addition, when updating of a plurality of areas is instructed on the DB editing screen, a record is generated for each area. In step S11, the user may operate the user terminal connected to the management device 3 to instruct data update. In this case, a data update instruction is transmitted from the user terminal to the management apparatus 3.

  By performing the processing as shown in FIG. 5, it is possible to register information related to data update at the local site in the update address table storage unit 11.

  Next, the replication process according to the present embodiment will be described with reference to FIGS. Before describing the specific processing flow, the processing mode will be described in detail. In this embodiment, five modes (mode 1 to mode 5) as shown in FIG. 6 are prepared, and when it is determined that the same area is updated at a plurality of bases in the replication process, the selected process is performed. In accordance with the priority conditions defined in the mode, it is determined which update contents of which base are prioritized. Hereinafter, each processing mode will be described.

  Mode 1 is a mode in which priority is given to the one with the highest number of updates during the period from the previous replication process to the current replication process. For example, as illustrated in FIG. 7, the areas of the address α and the address γ are updated at the base A (update count: 3), and the areas of the address α and the address β are updated at the base B (update count: 2). For the area of the address α updated at both bases, priority is given to the update contents of the base A with a large number of updates. Note that the areas of the address β and the address γ are updated only at one of the bases, so that the updated contents need only be reflected. That is, in each of the base A and the base B, the update contents of the base A are reflected in the areas of the address α and the address γ (the second update contents for the area of the address γ), and the areas of the address β are By reflecting the updated contents of the base B, the database 5 is synchronized. Note that the area updated only at one base is the same in the other modes.

  Mode 2 is a mode in which priority is given to the larger update target number from the previous replication process to the current replication process. For example, as shown in FIG. 8, the areas of the address α and address γ are updated at the base A (update target number: 2), and the areas of the address α, address β, and address δ are updated at the base B (update target number: In the case of 3), for the area of the address α updated at both bases, the update contents of the base B with a large number of update targets are given priority. That is, in each of the base A and the base B, the update content of the base A is reflected in the area of the address γ (the second update content), and the areas of the address α, the address β, and the address δ are The database 5 is synchronized by reflecting the updated contents.

  Mode 3 is a mode in which update dates and times are compared and priority is given to the later update time. For example, as shown in FIG. 9, when the area of the address α and the address β is updated at the base A and the area of the address α and the address γ is updated at the base B, the area of the address α updated at both bases With regard to, priority is given to the update contents of the base B with the latest update date and time. That is, in each of the base A and the base B, the updated contents of the base A are reflected in the area of the address β, and the updated contents of the base B are reflected in the areas of the address α and the address γ (address γ (Regarding the second area), the database 5 is synchronized.

  Mode 4 is a mode in which the difference between the update addresses is compared, and the smaller update address difference is prioritized. For example, as shown in FIG. 10, the area of the address α and the address β is updated at the base A (difference of update address = | address α−address β |), and the area of the address α and address γ is updated at the base B ( When the update address difference = | address α−address γ |), the update contents of the base A with a small update address difference are given priority for the area of the address α updated at both bases. Here, it is assumed that address α <address β <address γ. That is, in each of the base A and the base B, the update contents of the base A are reflected in the area of the address α and the address β, and the update contents of the base B are reflected in the area of the address γ. Are synchronized.

  Mode 5 is a mode in which priority is given to the person who becomes the head office (or the one with higher priority set for each base). For example, as shown in FIG. 11, when the areas of the address α and address β are updated at the base A (head office) and the areas of the address α and address γ are updated at the base B, the addresses updated at both bases. For the area of α, priority is given to the updated contents of the base A (head office). That is, in each of the base A and the base B, the update contents of the base A are reflected in the area of the address α and the address β, and the update contents of the base B are reflected in the area of the address γ. Are synchronized.

  Next, a specific processing flow of the replication processing according to the present embodiment will be described with reference to FIGS. Here, when the database 5 is synchronized between the site A and the site B, a replication process performed at the site A will be described as an example (hereinafter, the site A is referred to as its own site). First, the schedule management unit 351 of the replication control unit 35 refers to the schedule stored in the replication information storage unit 9 and determines whether the execution time of the replication process has been reached. When it is determined that the execution time of the replication process has been reached, the management device 3 performs a process as shown in FIG. Since the schedule is agreed between the bases, the replication process is started at the other bases at the same time.

  First, the communication unit 33 performs communication connection processing such as dial-up connection, for example, and connects to another site via the public network (FIG. 12: step S21). Then, the update address table acquisition unit 352 of the replication control unit 35 acquires the update address table from the update address table storage unit 11 of another base and stores it in the storage device (step S23). At this time, data excluding old data, operation details, and updater information stored in the update address table of another base (that is, update address, new data, and update date and time) may be acquired. Further, necessary data may be acquired according to the selected processing mode. Thereafter, the communication unit 33 performs a communication disconnection process, and ends the connection with another site (step S25). In addition, in the base B (other base), the updated address table is acquired from the base A (own base), but the connection is terminated in each base after the acquisition of the updated address table of the partner base is completed. . The communication connection and communication disconnection processing is not different from the conventional processing and will not be described further.

  Then, the determination unit 354 of the replication control unit 35 determines whether or not the same update address is included in the update address table of the local site and the update address table of the other site (step S27). When it is determined that the same update address is included in the update address table of the own site and the update address table of the other site (step S27: Yes route), that is, when the same area is updated in the own site and the other site The management device 3 performs the same address update process (step S29). Here, the update addresses included in both the update address table of the local site and the update address table of the other site are referred to as “same address”.

  The same address update process will be described with reference to FIGS. First, the tabulation processing unit 353 of the replication control unit 35 performs tabulation processing based on the update address tables of its own base and other bases (FIG. 13: step S41). Specifically, for each base, the records included in the update address table are sorted using the update address as a key, the number of updates and the number of update targets are totaled, and the count result is stored in the storage device.

  Then, the determination unit 354 of the replication control unit 35 acquires the processing mode from the replication information storage unit 9 (step S43), and determines whether the processing mode is set to “mode 1” (step S45). When the processing mode is set to “mode 1” (step S45: Yes route), the determination unit 354 extracts and compares the update counts of the local site and the local site stored in the storage device ( Step S47).

  When the number of updates at the local site is greater than the number of updates at the other site (step S49: Yes route), the processing of steps S51 to S55 described below is skipped and the processing returns to the original processing. That is, the update contents of the local site are reflected in the database 5, but since the database 5 has already been updated in the process of step S13 (FIG. 5) described above, no particular process is performed here.

  On the other hand, when the update count of the local site is less than or equal to the update count of the other site (step S49: No route), the DB update processing unit 355 of the replication control unit 35 is based on the update address table of the other site stored in the storage device. Then, the database 5 is updated (step S51). That is, the update contents of other bases are reflected in the area indicated by the same address in the database 5. In addition, the update discard notification unit 356 of the replication control unit 35 refers to the update address table storage unit 11 and identifies the user who updated the same address at the local site (step S53). Then, the update discard notification unit 356 of the replication control unit 35 acquires a mail address corresponding to the specific user from the user information storage unit 7, and transmits to the specific user an email indicating that the update content by the specific user has been discarded. (Step S55). Note that information for specifying the update target, update date and time, and the like may be included in the mail. Then, the process returns to the original process.

  On the other hand, if the processing mode is not set to “mode 1” in step S45 (step S45: No route), the determination unit 354 of the replication control unit 35 determines whether the processing mode is set to “mode 2”. (Step S57). When the processing mode is set to “mode 2” (step S57: Yes route), the determination unit 354 of the replication control unit 35 determines the update target numbers of the own site and other sites stored in the storage device. Extract and compare (step S59).

  When the update target number of the local base is larger than the update target number of the other base (step S61: Yes route), the DB update processing unit 355 of the replication control unit 35 skips the processing of step S51 to step S55 described above. Return to the original process. That is, the update contents of the local site are reflected in the database 5, but since the database 5 has already been updated in the process of step S13 (FIG. 5) described above, no particular process is performed here.

  On the other hand, when the update target number of the local base is less than or equal to the update target number of the other base (step S61: No route), the DB update processing unit 355 of the replication control unit 35 performs the processes of steps S51 to S55 described above. carry out. In addition, since the process of step S51 thru | or step S55 is not different from the process demonstrated above, description is abbreviate | omitted here. Then, the process returns to the original process.

  On the other hand, if the processing mode is not set to “mode 2” in step S57 (step S57: No route), the process proceeds to step S63 (FIG. 14) via the terminal A.

  Shifting to the description of the processing in FIG. 14, after the terminal A, the determination unit 354 of the replication control unit 35 determines whether the processing mode is set to “mode 3” (FIG. 14: step S63). When the processing mode is set to “mode 3” (step S63: Yes route), the determination unit 354 of the replication control unit 35 ends the data of the same address based on the updated address table of the local site and the other site. It is determined whether or not the updated site is the local site (step S65).

  If it is the local site that last updated the data of the same address (step S65: Yes route), the process returns to the process of FIG. 13 via the terminal B, and the processes of steps S51 to S55 described above are skipped. To return to the original process. That is, the update contents of the local site are reflected in the database 5, but since the database 5 has already been updated in the process of step S13 (FIG. 5) described above, no particular process is performed here.

  On the other hand, when the data of the same address was last updated at another base (step S65: No route), the process returns to the process of FIG. 13 via the terminal C, and the processes of steps S51 to S55 described above are performed. carry out. If there are a plurality of the same addresses, the process of step S65 and the processes of steps 51 to 55 (only when returning to FIG. 13 via the terminal C) are performed for each same address. Since the processing from step S51 to step S55 is the same as the processing described above, the description thereof is omitted here. Then, the process returns to the original process.

  On the other hand, if the processing mode is not set to “mode 3” in step S63 (step S63: No route), the determination unit 354 of the replication control unit 35 determines whether the processing mode is set to “mode 4”. (Step S67). When the processing mode is set to “mode 4” (step S67: Yes route), the determination unit 354 of the replication control unit 35 determines the difference between the same address and another update address for each of its own site and other sites. And the differences are compared (step S69). At this time, when a plurality of differences are calculated, the smallest difference at the local site is compared with the smallest difference at the other sites.

  When the difference at the local site is smaller than the difference at the other site (step S71: Yes route), the process returns to the process of FIG. 13 via the terminal B, skips the processes of steps S51 to S55 described above, Return to processing. That is, the update contents of the local site are reflected in the database 5, but since the database 5 has already been updated in the process of step S13 (FIG. 5) described above, no particular process is performed here.

  On the other hand, when the difference at the local site is greater than or equal to the difference at the other site (step S71: No route), the process returns to the process of FIG. 13 via the terminal C, and the processes of steps S51 to S55 described above are performed. If there are a plurality of the same addresses, the processes of steps S69 and S71 and the processes of steps 51 to 55 (only when returning to FIG. 13 via the terminal C) are performed for each same address. To do. Since the processing from step S51 to step S55 is the same as the processing described above, the description thereof is omitted here. Then, the process returns to the original process.

  On the other hand, if the processing mode is not set to “mode 4” in step S67 (step S67: No route), that is, if the processing mode is set to “mode 5”, the determination of the replication control unit 35 is performed. The unit 354 determines whether or not its own base is the head office (step S73). When priority is set for each base, the priorities may be compared to determine whether the priority of the local base is higher than the priority of other bases.

  If the base is the head office (step S73: Yes route), the process returns to the process of FIG. 13 via the terminal B, skips the processes of steps S51 to S55 described above, and returns to the original process. That is, the update contents of the local site are reflected in the database 5, but since the database 5 has already been updated in the process of step S13 (FIG. 5) described above, no particular process is performed here.

  On the other hand, when the base is not the head office (step S73: No route), the process returns to the process of FIG. 13 via the terminal C, and the processes of steps S51 to S55 described above are performed. In addition, since the process of step S51 thru | or step S55 is not different from the process demonstrated above, description is abbreviate | omitted here. Then, the process returns to the original process.

  Returning to the description of FIG. 12, if it is determined in step S27 that the same update address is not included in the update address table of the local site and the update address table of the other site (step S27: No route), the process proceeds to step S29. Skip processing.

  Then, the determination unit 354 of the replication control unit 35 determines whether there is an update address included only in the update address table of the other base (step S31). If it is determined that there is an update address included only in the update address table of the other base (step S31: Yes route), the DB update processing unit 355 of the replication control unit 35 updates the update address of the other base stored in the storage device. The database 5 is updated based on the table (step S33). That is, the update contents of other bases are reflected in the database 5.

  It should be noted that the area that has been updated only at its own site has not been particularly processed here because the database 5 at its own site has already been updated in the process of step S13 (FIG. 5) described above.

  On the other hand, if there is no update address included only in the update address table of the other base, the process of step S33 is skipped. Then, the replication control unit 35 resets the update address table of its own base stored in the update address table storage unit 11 (step S35). Then, this process ends.

  By carrying out the processing as described above, a database is set up for each base, and in a system in which each database is updated, even if the base is located in an area where the always-on service cannot be used, the database between the bases Can be synchronized. In addition, since the public line network 1 is used only while the update address table of another base is acquired, for example, if it is a pay-per-use line, the communication cost can be minimized. Furthermore, if the same area is updated at the local site and the other site, and the update content of the other site is reflected in the database 5, the user who instructed the update at the local site is notified, so this is necessary. Then, it can be updated again.

  Although one embodiment of the present invention has been described above, the present invention is not limited to this. For example, the functional block diagram described above does not necessarily correspond to an actual program module configuration. The management device 3 may be realized by a plurality of computers instead of a single computer.

  Further, the configuration of each table described above is an example, and the configuration as described above is not necessarily required. Further, in the processing flow, the processing order can be changed if the processing result does not change. Further, it may be executed in parallel.

  In the above, five processing modes have been described, but the number of modes is not limited to five. For example, a mode may be prepared in which priority is set for each user and priority is given to the update contents of the user with high priority.

  Moreover, although the example which synchronized the database 5 with the base A and the base B was demonstrated above, the number of bases may be three or more. In this case, the basic processing flow does not change, but when the same area is updated at two or more other bases, the processing stored in the replication information storage unit 9 between step S31 and step S33. According to the mode, a process for determining which update contents of other bases should be reflected in the database 5 of the local base may be added, and the process of step S33 may be performed based on the determination result.

  The management device 3 is a computer device as shown in FIG. 15, and includes a memory 2501 (storage device), a CPU 2503 (processing device), a hard disk drive (HDD) 2505, and a display control unit 2507 connected to the display device 2509. A drive device 2513 for the removable disk 2511, an input device 2515, and a communication control unit 2517 for connecting to a network are connected by a bus 2519. An operating system (OS: Operating System) and an application program for performing processing in the present embodiment are stored in the HDD 2505, and are read from the HDD 2505 to the memory 2501 when executed by the CPU 2503. If necessary, the CPU 2503 controls the display control unit 2507, the communication control unit 2517, and the drive device 2513 to perform necessary operations. Further, data in the middle of processing is stored in the memory 2501 and stored in the HDD 2505 if necessary. In the embodiment of the present invention, an application program for performing the processing described above is stored in the removable disk 2511 and distributed, and is installed in the HDD 2505 from the drive device 2513. In some cases, the HDD 2505 may be installed via a network such as the Internet and the communication control unit 2517. Such a computer apparatus realizes various functions as described above by organically cooperating hardware such as the CPU 2503 and the memory 2501 described above, the OS, and necessary application programs.

Claims (7)

A replication processing method in the case of performing communication between bases using a narrowband line,
When a database update instruction is received from a user, the database is updated according to the update instruction, and at least an update address indicating an area to be updated and updated data are stored in a first update address table Steps,
At a predetermined timing, connect to another base, obtain a second update address table storing an update address related to update at the other base and updated data, and connect to the other base. An acquisition step to end;
When the same update address is stored in the first update address table and the second update address table, the first update address table and the first update address table correspond to the update address according to a predetermined rule. Identifying any of the updated data stored in the update address table of 2 as data to be reflected in a corresponding area in the database indicated by the update address;
A second update step of updating a corresponding area in the database with the updated data when the updated data stored in the second update address table is specified as the data to be reflected;
A replication processing method executed by a computer. 2. The method according to claim 1, further comprising a step of notifying the user who has instructed to update the corresponding area in the database of discarding the update data when the corresponding area in the database is updated by the second update step. Replica processing method. The predetermined rule is:
Rules that prioritize sites with a large number of updates, rules that prioritize sites with a large number of updates, rules that prioritize sites with a late update date, rules that prioritize sites with small differences in update addresses, or preset priorities The replication processing method according to claim 1, wherein the rule gives priority to a base having a high degree.   The replication processing method according to claim 1, wherein the steps after the acquisition step are executed according to a preset schedule.   2. The replication processing method according to claim 1, wherein the narrowband line is a metered line. A program for synchronizing databases between sites using a narrowband line,
When a database update instruction is received from a user, the database is updated according to the update instruction, and at least an update address indicating an area to be updated and updated data are stored in a first update address table Steps,
At a predetermined timing, connect to another base, obtain a second update address table storing an update address related to update at the other base and updated data, and connect to the other base. An acquisition step to end;
When the same update address is stored in the first update address table and the second update address table, the first update address table and the first update address table correspond to the update address according to a predetermined rule. Identifying any of the updated data stored in the update address table of 2 as data to be reflected in a corresponding area in the database indicated by the update address;
A second update step of updating a corresponding area in the database with the updated data when the updated data stored in the second update address table is specified as the data to be reflected;
A replication processing program for causing a computer to execute. A management device for synchronizing databases between bases using a narrowband line,
When a database update instruction is received from a user, the database is updated according to the update instruction, and at least an update address indicating an area to be updated and updated data are stored in a first update address table Means,
At a predetermined timing, connect to another base, obtain a second update address table storing an update address related to update at the other base and updated data, and connect to the other base. An acquisition means to terminate;
When the same update address is stored in the first update address table and the second update address table, the first update address table and the first update address table correspond to the update address according to a predetermined rule. Means for specifying any of the updated data stored in the update address table of 2 as data to be reflected in a corresponding area in the database indicated by the update address;
When the updated data stored in the second update address table as the data to be reflected is specified, second update means for updating a corresponding area in the database with the updated data;
A management device.

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