JP2000003300A - Automatic duplicating device for data base, its method, system therefor and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mutually copy the updating data without carrying on the copying processes among plural data bases by preparing a means which updates a copying data base contained in a slave machine based on the updating data which are distributed by a distribution means of a master machine. SOLUTION: A data base of every computer (a master machine 13 and slave machines 14 to n) consists of a data updating exclusive table TA, i.e., a data updating exclusive data base and a copy table TB, i.e., a copying data base. Then the machine 13 updates its own table TA and the tables TB based on its own inputted updating data and also updates its own table TB based on the updating data which are transferred from the machines 14 to n. Furthermore, the machine 13 distributes the updating data transferred from the machines 14 to n to all machines 14 to n.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic data duplication technique for making data contents of a database managed by a plurality of computers on a network identical.

[0002]

2. Description of the Related Art Conventionally, as an automatic data duplication technique for making data contents of a database managed by a plurality of computers on a network the same,
Although a one-way data replication method has been realized, a bidirectional data replication technology has not been realized.

In this one-way data replication method, when it is necessary to update the database, for example, the database on the master computer is updated, and the updated data is transmitted from the master computer to all slave computers. In this case, data is automatically transferred and data is copied, and data cannot be updated from a slave computer.

When it is necessary to update the database, for example, the database on the slave computer is updated, and the updated data is automatically transferred from the slave computer to the master computer to copy the data. And the data cannot be updated from the master computer.

[0005]

However, when such a one-way database replication method is used to automatically replicate each other between databases on each computer, the following problem occurs. It is expected that things will happen.

For example, consider a simple system in which a database Da on a computer A and a database Db on a computer B exist, and an example in which they are automatically copied to each other. In this system, if the database Da on the computer A is updated (addition, correction, deletion, etc. of data), the database Db on the computer B is updated based on the updated data, so that the copying process is performed. Will be As described above, when the copy processing (data update) is performed on the computer B, data related to the copy processing on the computer B, that is,
The database Da on the computer A is updated based on the same data as the contents of the database Da on the current computer A.

[0007] Thereafter, a similar copying process (copying process) is performed between the computer A and the computer B. As described above, once the database is updated, the process of copying the updated data is permanently continued between the plurality of databases.

SUMMARY OF THE INVENTION The present invention has been made in view of such a background, and an object of the present invention is to prevent a plurality of databases from replicating update data of the databases while avoiding the processing to be permanently continued between the plurality of databases. An object of the present invention is to make it possible to mutually replicate database update data between databases.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to an automatic database duplication apparatus for mutually duplicating databases managed by computers on a network. An update database dedicated to data update, and a copy database dedicated to copying, wherein the master computer of the computers is configured to update the data in the master computer based on update data input from the master computer. First updating means for updating a database and a copying database; second updating means for updating a copying database in the master computer based on update data transferred from another slave computer; Update data transferred from the slave computer Distribution means for distributing to all slave computers on the network, wherein the slave computer updates an update database in the slave computer based on update data input from the slave computer. Means, transfer means for transferring update data input from the slave computer to the master computer,
And a fourth updating unit for updating a copy database in the slave computer based on the update data distributed by the distribution unit of the master computer.

The present invention also relates to a method of automatically duplicating a database for mutually duplicating a database managed by each computer on a network, the computer comprising: an update database dedicated to data update; A copying database dedicated to copying, wherein a master computer of the computers updates the updating database and the copying database in the master computer based on update data input from the master computer. Update step, a second update step of updating a copy database in the master computer based on update data transferred from another slave computer, and updating the transfer data transferred from the other slave computer. All slaves on the network A distribution step of distributing the data to a computer, wherein the slave computer updates the update database in the slave computer based on update data input from the slave computer; and A transfer step of transferring the input update data to the master computer; and a fourth update step of updating a copy database in the slave computer based on the update data distributed by the distribution step of the master computer. ing.

The present invention is also an automatic database replication system for mutually copying databases managed by computers on a network,
The computer includes an update database dedicated to data update, and a copy database dedicated to copying,
A master computer among the computers includes a first update unit that updates an update database and a copy database in the master computer based on update data input from the master computer; Second updating means for updating the copy database in the master computer based on the transferred update data, and distributing the update data transferred from the other slave computer to all slave computers on the network Distribution means, the slave computer, based on the update data input from the slave computer,
Third update means for updating the update database in the slave computer, transfer means for transferring update data input from the slave computer to the master computer, and update data delivered by the delivery means of the master computer Fourth updating means for updating the copy database in the slave computer based on the

The present invention is also a storage medium for storing a control program for automatically duplicating a database by mutually duplicating a database managed by each computer on a network. The computer includes an update database dedicated to data update, and a copy database dedicated to copying, and the control program executed by a master computer of the computers is configured to update data input from the master computer. A first update routine for updating the update database and the copy database in the master computer, and updating the copy database in the master computer based on update data transferred from another slave computer. A second update routine, And a distribution routine for distributing update data transferred from another slave computer to all slave computers on the network, wherein the control program executed by the slave computer is input from the slave computer. A third update routine for updating the update database in the slave computer based on the update data, a transfer routine for transferring the update data input from the slave computer to the master computer, and a distribution routine for the master computer And a fourth update routine for updating the copy database in the slave computer based on the update data distributed by the computer.

Further, in the present invention, the master computer and the slave computer include a plurality of update databases and copy databases in which data of various fields are integrated.

[0014]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a system configuration diagram of an information processing system to which an automatic database copy apparatus according to an embodiment of the present invention is applied. In this information processing system, a plurality of computers 13, 14, 15,... N each functioning as a database server are connected via a network N.

The computer 13 includes all the computers 13 and 1 connected to the network N.
, N, and receives the update data of the database on the other computers 14, 15,.
n, and the computers 14 to n are configured to function as slave machines to the master machine.

As shown in FIG. 2, each of these computers 13 to n has a central processing unit 1, a main storage unit 2, an auxiliary storage unit 3, an input unit 4, an output unit 5, and a network I / F 6. are doing. Computer 13 ~
Each of the n auxiliary storage devices 3 stores a database. The main storage device 2 stores a control program for performing a later-described automatic replication process of a database, and the central processing unit 1 performs automatic replication of a later-described database according to a control program in the main storage device 2. Perform processing.

The input device 4 is constituted by a keyboard, a mouse and the like, and inputs update data of a database, an update command, and the like. I do. Further, the network I / F 6 is used to transfer update data of the database and the like to another computer.

As shown in FIGS. 3 to 5, the database is composed of a data update-dedicated table TA used for data update and a copy table TB. It should be noted that the data update-dedicated table TA and the copy table TB store data of the same content (strictly, not completely identical).

In this embodiment, the master machine 13 and the slave machines 14 to 14 are transferred by transmitting the update data along the paths shown by arrows in FIGS.
The update data (that is, the copy table) is mutually replicated among n.

That is, the data update dedicated table TA
Is updated only by the update data input by the master machine 13 or the slave machines 14 to n equipped with the data update dedicated table. In other words,
The data update-dedicated table TA is updated by self-input update data, and is not updated by update data input from another machine.

On the other hand, the copy table TB is updated by the update data inputted by all the computers (master machine 13 and slave machines 14 to n) on the network N, whereby the copy tables on all the computers are updated. The contents of the TB completely match.

Although FIGS. 3 to 5 show only one type of database table, the auxiliary storage device 3 actually stores a plurality of database tables in which information in various fields is accumulated. Is stored.

Next, by transferring the update data along the path indicated by the arrows in FIGS. 3 to 5, a copy process of mutually copying the update data between the master machine 13 and the slave machines 14 and 15 is performed. 6 to 9 will be described.

First, a series of processes for monitoring the data update table TA of the master machine 13 and updating the copy table TB of the master machine 13 will be described with reference to the flowchart of FIG.

In the master machine 13, a series of processing according to the flowchart of FIG. 6 is executed when the computer is started or when a program execution instruction is issued.
First, it is determined whether or not to end this processing (step S
1) If it is determined to end, the process ends. When the update data D1 in FIG. 3 occurs, the data is updated in a dedicated table (data update dedicated table TA) for updating the data (see arrow a1 in FIG. 3).

If it is determined that the process is not to be terminated, the data update dedicated table TA of the master machine 13 is checked (step S2), and it is determined whether or not the data has been updated (step S3). As a result, if the data has not been updated, the process returns to step S1. On the other hand, if the data has been updated, the update data is obtained (step S4, see arrow a2 in FIG. 3), and the copy table TB in the master machine 13 is updated based on the obtained update data. (Step S
5) Return to step S1.

Next, the process of monitoring the copy table TB of the master machine 13 and transferring update data to the slave machines 13 to n connected to the network N will be described with reference to the flowchart of FIG.

In the master machine 13, a series of processes according to the flowchart of FIG. 7 are executed when the computer is started or in response to an instruction to execute a program. First, it is determined whether or not to end this process (step S1).
1) If it is determined to end, the process ends.

On the other hand, if it is determined that the update is not to be completed, it is determined whether or not the update data has been transferred from the slave machines 14 to n (step S12, arrow a in FIG. 4).
5, see arrow a8 in FIG. 5). As a result, when the update data is transferred, the copy table TB in the master machine 13 is updated based on the transferred update data (step S13). Then, the copy table TB in the master machine 13 is checked (step S1).
4) It is determined whether the data has been updated (step S15). If it is determined in step S12 that the update data has not been transferred, the process of updating the copy table TB in step S13 is skipped and step S1 is executed.
Proceeding to step S4, it is checked whether the data of the copy table TB in the master machine 13 has been updated.

At step S15, master machine 13
If it is determined that the data of the copy table TB has not been updated, the process returns to step S11. On the other hand, when it is determined that the data of the copy table TB has been updated,
The update data is acquired (step S16), and the update data is transferred to all slave machines 1 via the network N.
4 to n (step S17, arrow a6 in FIG. 4).
a7, see arrows a9 and a10 in FIG. 5), step S11
Return to

Next, the data update dedicated table TA of the slave machines 14 to n is monitored, and the updated data is
A series of processes to be transferred to the machine 13 will be described with reference to the flowchart of FIG.

In the slave machines 14 to n, FIG.
Is executed when the computer is started or in response to an instruction to execute a program. First, it is determined whether or not to end the present process (step S21). ,finish.
When the update data D2 and D3 shown in FIGS. 3 and 4 are generated, the data is updated in a dedicated table for updating the data (data update dedicated table TA).

Therefore, if it is determined that the present processing is not to be ended, the data updating dedicated table TA of its own (slave machine 14 to n) is checked (step S22).
It is determined whether the data has been updated (step S2).
3). As a result, if the data has not been updated,
It returns to step S21. On the other hand, if the data has been updated, the updated data is obtained (step S2).
4). Then, the acquired update data is transferred to the master machine 13 via the network N (step S2).
5, see arrow a5 in FIG. 4 and arrow a8 in FIG. 5), and return to step S21.

Next, in the slave machines 14 to n, the processing of updating the copy table TB of the own machine (slave machines 14 to n) based on the update data transferred from the master machine 13 is shown in FIG. This will be described according to the flowchart of FIG.

In the slave machines 14 to n, FIG.
A series of processes according to the flowchart are executed when the computer is started or in response to a program execution instruction, and it is first determined whether or not to end the present process (step S
31) If it is determined to end, the process ends.

On the other hand, if it is determined that the update is not to be completed, it is determined whether or not the update data has been transferred from the master machine 13 (step S32, arrows a6 and a in FIG. 4).
7, see arrows a9 and a10 in FIG. 5). As a result, if the update data has not been transferred, the process returns to step S31. On the other hand, if the update data has been transferred, the copy table TB of its own (slave machine 14 to n) is updated based on the transferred update data (step S33), and the process returns to step S31.

As described above, in the present embodiment, the database on each computer is constituted by the data update-dedicated table TA which is a database exclusively for data update, and the copy table TB which is a database for copy. I have. Then, based on the self-input update data, master machine 13 uses its own data update table T
A and the copy table TB are updated.
It updates its own copy table TB based on the update data transferred from the machines 14-n,
The update data transferred from the machines 14 to n is distributed to all the slave machines 14 to n.

On the other hand, the slave machines 14 to n update their own data update-dedicated table TA based on the self-input update data, and transfer the updated data to the master machine 13.・ Machine 13
Updates its own copy table TB on the basis of the update data distributed from.

Therefore, based on the update data that has been generated once, it is possible to prevent the harmful effect that the copying process is continuously performed between the plurality of databases forever, and to exchange the update data (database) between the plurality of databases. Copy
Processing becomes possible.

[0041]

As described above, according to the present invention,
An automatic duplication apparatus for a database for mutually copying between databases managed by computers on a network, wherein the computer includes an updating database dedicated to data updating and a copying database dedicated to copying. A first updating means for updating an update database and a copy database in the master computer based on update data inputted from the master computer, and another slave computer Second updating means for updating the copy database in the master computer based on the update data transferred from the master computer, and updating the update data transferred from the other slave computer to all slave computers on the network. Delivery hand to deliver And a third updating unit that updates an update database in the slave computer based on update data input from the slave computer, and updates the input data from the slave computer. A transfer unit that transfers the data to the master computer; and a fourth update unit that updates the copy database in the slave computer based on the update data distributed by the distribution unit of the master computer. The update data of the database can be mutually replicated among the plurality of databases while avoiding the data replication process from continuing forever between the plurality of databases.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of an information processing system to which a database automatic copying apparatus according to an embodiment of the present invention is applied.

FIG. 2 is a block diagram showing a hardware configuration common to each computer in the information processing system of FIG. 1;

FIG. 3 is an image diagram showing a flow of update data in a copy process when update data occurs in a master machine.

FIG. 4 is a conceptual diagram showing a flow of update data in a replication process when update data occurs in a slave machine.

FIG. 5 is a conceptual diagram showing a flow of update data in a copy process when update data occurs in another slave machine.

FIG. 6 is a flowchart showing a process of monitoring a data update-dedicated table of a master machine and copying update data to a copy table.

FIG. 7: Update data is transferred from a master machine to a slave machine.
It is a flowchart which shows the process which distributes to a machine.

FIG. 8 is a flowchart showing a process of monitoring a data update dedicated table of a slave machine and transferring update data to a master machine.

FIG. 9 is a flowchart showing a process of monitoring transfer of update data from a master machine and updating a copy table.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Central processing unit 2 Main storage device 3 Auxiliary storage device 13 Master machine 14, 15, n Slave machine N Network TA Copy table TB Data update dedicated table D1, D2, D3 Update data

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Maki Kanchokura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Jun Ogawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Kia Non-corp. F term (reference) 5B082 GA14 HA03 HA05 5B089 AA16 AC07 AD02 AF05 CB02 CB03 DD18

Claims (5)

[Claims] 1. An automatic copying apparatus for a database for mutually copying between databases managed by respective computers on a network, wherein the computers each include an updating database exclusively for updating data and a copying database exclusively for copying. A first update unit that updates the update database and the copy database in the master computer based on update data input from the master computer. Second updating means for updating a copy database in the master computer based on update data transferred from another slave computer; and updating update data transferred from the other slave computer on the network. All slave computers Distribution means for distributing, wherein the slave computer is configured to update an update database in the slave computer based on update data input from the slave computer, and input from the slave computer. Transfer means for transferring the updated data to the master computer, and fourth updating means for updating a copy database in the slave computer based on the update data distributed by the distribution means of the master computer. Automatic database replication apparatus characterized by the following. 2. An automatic replication method of a database for mutually copying between databases managed by respective computers on a network, wherein the computers each include an updating database exclusively for data updating and a copying database exclusively for copying. A first update step of updating the update database and the copy database in the master computer based on update data input from the master computer. A second update step of updating a copy database in the master computer based on update data transferred from another slave computer; and updating the copy data transferred from the other slave computer on the network. All slave computers A distribution step of distributing, wherein the slave computer is configured to update a database for updating in the slave computer based on update data input from the slave computer; A transfer step of transferring the updated data to the master computer, and a fourth update step of updating a copy database in the slave computer based on the update data distributed by the distribution step of the master computer. Automatic replication method of database characterized by the following. 3. An automatic database replication system for mutually duplicating databases managed by computers on a network, said computers comprising: an update database dedicated to data update; and a copy database dedicated to copy. A first update unit that updates the update database and the copy database in the master computer based on update data input from the master computer. Second updating means for updating a copy database in the master computer based on update data transferred from another slave computer; and updating update data transferred from the other slave computer on the network. All slave computers Distribution means for distributing data to the slave computer, wherein the slave computer is configured to update an update database in the slave computer based on update data input from the slave computer; and Transfer means for transferring the input update data to the master computer; and fourth update means for updating a copy database in the slave computer based on the update data distributed by the distribution means of the master computer. An automatic database replication system. 4. A storage medium for storing a control program for automatically duplicating a database by mutually duplicating a database managed by each computer on a network, wherein the computer comprises: An update database dedicated to data update and a copy database dedicated to copying are provided, and the control program executed by the master computer of the computers is based on update data input from the master computer. A first update routine for updating the update database and the copy database in the master computer; and a second update routine for updating the copy database in the master computer based on update data transferred from another slave computer. An update routine and the other slave A distribution routine for distributing update data transferred from the computer to all slave computers on the network, wherein the control program executed by the slave computer is based on update data input from the slave computer. A third update routine for updating the update database in the slave computer, a transfer routine for transferring update data input from the slave computer to the master computer, and a distribution routine for the master computer. And a fourth update routine for updating a copy database in the slave computer based on the update data. 5. The automatic replication of a database according to claim 1, wherein the master computer and the slave computer include a plurality of update databases and a copy database in which data in various fields are accumulated. Apparatus, automatic duplication method, automatic duplication system, and storage medium.