JPH11296422A - Data copying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically suppress double update in spite of the routing of a transfer route by adding an identifier specifying the uniqueness of an information processor where information is updated to update information and inspecting update information at the time of transferring or receiving it. SOLUTION: An identifier specifying the uniqueness of an information processor where information is updated is added to update information and update information is inspected at the time of transferring or receiving it. In an information processor 4, a data copying device 12 updates a data base 8 based on update information transferred with the information processor 1 as a start, extracts update information 27 and adds an update source identifier 28. At the time of inspecting the update identifier 28 when information is transferred to the information processor 1 being a transfer source, it becomes clear that the information processor 1 is an update source, and therefore the transfer of update information 27 to the information processor 1 is suppressed. Namely, update processing generated in the information processors 1 is prevented from being transferred again to the information processor 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a computer system connected to a large number of networks by duplicating data updates, such as database replication, transferring the data updates to another information processing apparatus, and reproducing the updated data. The present invention relates to an apparatus for duplicating data.

[0002]

2. Description of the Related Art In a distributed database asynchronous update function disclosed in Japanese Patent Application Laid-Open No. 9-54718, a database or a part thereof distributed to each site in a distributed database environment distributed by a plurality of networks and connected to a network is stored in its own site. It is a distributed database that has a replica that is a replica of it, and synchronizes the original database of its own site with the replica between the sites. On the other hand, the data update generated not only from the central database but also from each information processing device is successively propagated to a plurality of information processing devices, and the data is duplicated by being reproduced in each information processing device. In the system, if the update is reproduced again in the information processing device at the source or passing point, an incorrect result such as double addition of data or an update error occurs, thereby breaking the data consistency between the information processing devices. Sometimes. Such an illegal update routing can be prevented by carefully determining a transfer route of the update information in advance. However, as the number of information processing devices performing the update copy increases and the network configuration becomes complicated, the transfer route of the update route is increased. It takes a lot of effort in routing decisions. There is also a technique in which the routing of a transfer path between information processing devices related to copying of updates on a network is managed by a single node. However, even in this case, the work of determining the routing of the transfer path is required.

[0003]

Even when routing is configured such that update information is transferred to the information processing device at the origin or point of entry and updated again, the system on each information processing device is automatically By providing the function of suppressing the update, the labor of the routing configuration can be reduced, and the consistency between the information processing apparatuses on the network can be improved by suppressing the unauthorized update.

[0004]

SUMMARY OF THE INVENTION The present invention specifies the uniqueness of an information processing apparatus that has been updated with respect to update information that is extracted and transferred to another information processing apparatus each time data is updated. This is a data copying apparatus that automatically suppresses double update irrespective of the transfer route by providing a function of adding an identifier and checking the update information when transferring or receiving the information.

[0005]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration example of a database replication system using a data copying apparatus to which the invention of claim 1 is applied. Information processing devices 1, 2,
Reference numerals 3 and 4 denote databases 5, 6, 7,..., 8 and data copying apparatuses 9, 10, 11, 12 to which the present invention is applied, respectively.
have. The data copying device 9 includes an update information extraction function 13,
It comprises an update information storage file 14, an update information transfer function 15, and an update information reception / reflection function 16. Similarly, the data copying apparatus 10 includes an update information extraction function 17, an update information storage file 18, an update information transfer function 19, and an update information reception / reflection function 20.

The update process 21 generated in the information processing apparatus 1 updates the data 22 of the database 5, and the update information is extracted by the update information extracting function 13 of the data copying apparatus 9;
It is stored as update information 23 in the update information storage file 14. At this time, a column 24 for writing the location information of the update source is added to the update information 23. At this stage, no information is set in the update source position information column 24. The update information 23 is transferred by the update information transfer function 15 to a preset information processing device.

In the information processing apparatus 2, the data copying apparatus 1
The update information reception / reflection function 17 of 0 receives the update information 23 transferred from the information processing apparatus 1 and updates the data 24 of the database 10 in the same manner as the database 5 based on the update information 23. The information 23 is the information processing device 1
From the update information extracting device 1
8 is set to a reference position. Update information extraction device 18
Extracts the update to the data 24 and stores it as update information 25 in the update information storage file 19. At this time,
An identifier 26 indicating the location information of the update source information processing apparatus 1 set by the update information receiving / reflecting function 17 for the update information 25
Is added. The update information 25 is transferred to the preset information processing device 3 by the update information transfer function 20. At this time, the update source identifier 26 added to the update information 25 is checked, and the set transfer destination information processing is performed. Since the information does not match the device 3, the update information 25 is transferred, and at the same time when the data copying device 11 similarly updates the database 7,
The update information is transferred to the information processing device set as the next transfer destination.

In the information processing device 4, the data copying device 12 updates the database 8 based on the update information transferred from the information processing device 1 as a starting point, and at the same time, extracts the update information 27 and adds the update source identifier 28. . When the update source identifier 28 is inspected at the time of transfer to the information processing apparatus 1 of the transfer destination set in advance, it is determined that the information processing apparatus 1 is the update source, and the update information 27 is transmitted to the information processing apparatus 1. Suppress forwarding. Thus, it is possible to prevent the update process 21 generated in the information processing device 1 from being transferred to the information processing device 1 again via the data copying device of each information processing device.

FIG. 2 is a block diagram of a first embodiment of each information processing apparatus.
10 is a flowchart of a data copying process according to the invention of FIG.
However, in the information processing device that is the starting point of the update process,
The process is started not from the update information reception process in the process 31 but from the update process to the database body in the process 32. Judgment 36
Thus, the data copying process is repeatedly executed until the information processing device at the transfer destination matches the update source.

FIG. 3 shows a configuration example of a database replication system using a data copying apparatus to which the invention of claim 2 is applied. Information processing device 41, 4
2, 43 and 44 are databases 45 and 46, respectively.
47, 48 and data copying apparatuses 49, 5 to which the present invention is applied.
It has 0, 51, and 52. The data copying device 49 includes an update information extraction function 53, an update information storage file 54, an update information transfer function 55, and an update information reception / reflection function 56. Similarly, the data copying apparatus 50 includes an update information extraction function 57, an update information storage file 58, an update information transfer function 5,
9. The update information reception / reflection function 60 is provided.

Update processing 61 generated in the information processing device 41
Updates the data 62 in the database 45, and the update information extraction function 53 of the data copying device 49 extracts the update information and stores it as update information 63 in the update information storage file 54. At this time, the update information 63 includes the update source position information 64.
Is added, and an identifier indicating the position information of the information processing device 41 is set. The update information 63 is transferred to a preset information processing device by the update information transfer function 55.

In the information processing device 42, the update information receiving / reflecting device 60 of the data copying device 50 is
1 before updating the data 65 of the database 46 based on the received update information 63, the update source position information 64 added to the update information 63 is checked, and the position of the information processing device 42 is checked. If the information is not set, an update process is performed, and at the same time, the update information extracting function 57 extracts an update to the data 65 of the database 46 and stores it as the update information 66 in the update information storage file 58.
At this time, the update source location information 67 is added to the update information 66,
The position information of the information processing device 42 is set. Update information 66
Is transferred to the preset information processing device 3 by the update information transfer function 59, and the data copying device 51 updates the database 47.

In the information processing device 44, the information processing device 4
1 based on the update information transferred from
2 updates the database 48, and at the same time, extracts update information 67 and adds an update source identifier 68. Update 6
7 is transferred to the information processing apparatus 41 of a preset transfer destination. In the information processing device 41, the update information receiving / reflecting device 56 of the data copying device 49 receives the transferred update information, and based on the received update information,
Before the update is performed, the update source position information 68 added to the update information 67 is checked. Here, it recognizes that the update information 67 is update information generated from its own information processing apparatus, and suppresses the process of updating the database 45. This prevents unauthorized update processing (double update for the same data) to the information processing apparatus 1.

FIG. 4 shows a first embodiment of each information processing apparatus.
10 is a flowchart of a data copying process according to the invention of FIG.
However, in the information processing device that is the starting point of the update process,
Instead of starting from the reception processing of the processing 71, the processing is started from the processing of updating the database body in the processing 73. In the determination 72, the data copying process is repeatedly executed until the own information processing device matches the update source.

[0016]

According to the present invention, in a system for replicating data by propagating data updates between a plurality of information processing apparatuses, the update information is transmitted to an information processing apparatus corresponding to an origin or a transfer passing point. And automatically prevents unauthorized update in which double update processing occurs. As a result, not only secure data replication is performed, but also complicated routing setting work for preventing unauthorized update processing in data replication is not required, so that the cost for system construction can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a system configuration of a database replication system according to an embodiment of the present invention.

FIG. 2 is a flowchart of a process applied to a database replication system described in FIG. 1 of the present invention.

FIG. 3 is a diagram showing a system configuration example of a database replication system according to another embodiment of the present invention.

FIG. 4 is a flowchart of processing applied to a database replication system described in FIG. 3 of the present invention.

[Explanation of symbols]

1, 2, 3, 4, 41, 42, 43, 44 ... Information processing device 5, 6, 7, 8, 45, 46, 47, 48 ... Database 10, 11, 12, 49, 50, 51, 52 ... Data copy device 13, 17, 53, 57 ... Update information extraction function 14, 18, 54, 58 ... Update information storage file 15, 19, 55, 59 ... Update information transfer function 16, 20, 56, 60 ... Update information reception -Reflection function 21, 61 ... Update operation to database 22, 25, 62, 65 ... Update data of database 26, 28, 63, 66, 68 ... Update information extracted from database 24, 27, 29, 64, 67, 69… Update source position information added to the update information

Claims (2)

[Claims] In a data processing system in which a plurality of information processing apparatuses exist on a network and data stored in each information processing apparatus is updated, one of the information processing apparatuses A function to extract updates made to the information and record it as update information, a function to transfer the update information to another information processing device, and a function to reproduce updates based on the update information transferred from the original information processing device Has the ability to
When extracting and transferring new update information generated by an update that is reproduced based on the update information received from the original information processing device, identify the uniqueness of the information processing device that is the transfer source of the update information on the network A new identifier, and when transferring the update information to another information processing device, the identifier of the transfer source information processing device is determined. If the update information matches the transfer source, the transfer is not performed. Data copying device. 2. In a data processing system in which a plurality of information processing apparatuses exist on a network and data stored in each information processing apparatus is updated, one of the information processing apparatuses A function to extract updates made to the information and record it as update information, a function to transfer the update information to another information processing device, and a function to reproduce updates based on the update information transferred from the original information processing device Has the ability to
For the update information to be transferred, a list is added to store an identifier that can specify the uniqueness of the information processing apparatus on which the update information has been generated or passed on the network, and the list is stored. Examine the list of identifiers of the added information processing devices, and if the information has passed through the information processing device, suppress updates.If not, reproduce the update based on the received update information. In addition, when extracting and recording new update information generated thereby, an update is performed by adding an identifier of the information processing apparatus on the network to the update information and transferring the update information to another information processing apparatus. A data copying apparatus characterized in that the data copying apparatus is prevented from being transferred again.