JP2000112801A - Data base backup system and backup method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the time and work related to the backup and recovery of data bases. SOLUTION: The data base backup system related to data base management parts is provided with three or more data bases 102, 104, and 106 connected on a network, data base servers 101, 103, and 105 corresponding to the respective data bases and data base management parts 111, 113, and 115 consisting of respectively independent software included in the data base servers and a data operation request is transferred between the data base management parts by using a common access language to be interpreted by the data base management parts. Thereby, an updating request from a master data base management part is transmitted to other data base management parts, the updating is reflected also to the other data bases. Further, even when a fault is generated in the master data base management part and since the data base backup system is data base management parts consisting of the respectively independent software, another data base management part is made as a master to continue job operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a database system for performing management while maintaining consistency among a plurality of databases in, for example, an update process in a database such as inventory management by an application program.

[0002]

2. Description of the Related Art Conventionally, data accessed by a database management unit is regularly backed up and managed in preparation for a sudden system failure. For this backup, a unique backup system provided by each database is used, and the backup data is stored and recorded in an auxiliary storage device such as a magnetic disk or a magnetic tape device in a unique data structure.

In the event that a database actually fails and operation becomes impossible, a series of processing is stopped and backup data stored and recorded up to that time is recovered by a recovery system provided by the database management unit. Data will be restored to the state immediately before the failure occurred.

[0004]

As described above, in the conventional database backup system, the backup operation itself is complicated, and the skill of the system operator is required in the operation, and careful training and enormous execution time are required. And As a result, there is a problem that the comprehensive cost of the entire database management system or the entire computer system increases.

In addition, when a failure occurs in the master database, the processing is interrupted by the system operator,
There is a problem that the recovery process must be performed and the master database cannot be easily recovered.

Furthermore, if there is a logical failure (software bug) in the conventional backup program or recovery program or the database management unit that manages the program, there is a problem that recovery from backup data may not be possible. is there. This problem is considered to be caused by the fact that even if a plurality of databases are used, the database management unit that manages them uses the same software.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. A backup system itself is simplified, and a backup system and database management are performed on a database management unit which eliminates the tasks required for backup operation. The purpose is to provide a backup method by the department.

Another object of the present invention is to provide a database management unit which simplifies the work required for recovery and enables smooth operation so that processing is not affected even if a failure occurs in the database. It is an object to provide a backup system and a backup method by a database management unit.

A further object of the present invention is to execute a process using a database management unit which does not cause a failure and a database for the database management unit even if a database failure occurs due to a logical failure of the database management unit itself. Accordingly, an object of the present invention is to provide a backup system on a database management unit and a backup method by the database management unit, which can enhance the security of the database.

[0010]

According to a first aspect of the present invention, there is provided a database backup system according to the first aspect of the present invention, which includes three or more databases connected on a network, and a plurality of databases connected to each of the databases. A database management unit comprising independent software included in the database server, and receiving a data operation request between the database management units using a common access language interpreted by the database management unit. And a communication interface for passing.

According to a second aspect of the present invention, in the database backup system, the database management unit on the database server device simultaneously transmits the standard data manipulation language to another different database management unit on the same network. And a data operation transmission program for performing the operation.

According to a third aspect of the present invention, in the database backup system according to the present invention, the database management unit on the database server device transmits the standard data operation language to all other different database management units on the same network. It is characterized in that the contents of the databases on the same network are made consistent by accessing them simultaneously and updating the contents of each database.

According to a fourth aspect of the present invention, in the database backup system according to the present invention, when a failure occurs in the master database system, the master database server and the master database are separated from the processing and the alternate master database server and the alternate master database are determined. And a recovery system that incorporates the master data server and the master database disconnected after the failure recovery into the processing again as the master.

According to a fifth aspect of the present invention, there is provided a database backup method according to the present invention, wherein a database system includes three or more databases connected on a network, and database servers corresponding to the respective databases. Receiving a data operation request from a client and operating a corresponding database; transmitting a data operation request to another database server using a common access language simultaneously with the operation of the database; and And a step of operating a corresponding database by the database server that has received the data operation request.

According to the database backup system and method of the present invention described in claims 1, 2, 3, 4, and 5, the database systems on the same network have different database management units on each database server. Running on the same software with different software or versions. Since each database management unit can operate data in a common access language, the same operation as data operation on the master database can be performed on other database management units. The common access language to the master database server is also distributed to other database servers by a common access language transmission program linked to the application program. The language received by other database servers is also a common access language, and can be understood by any database management unit. As a result, a plurality of database management units can have consistent data by a common access language even if the installed software is different.

That is, the common access language received by another database server and transmitted on the network is executed in the database management unit. The database update request is transmitted as a common access language, and each database structure is independently managed by a database management unit on a corresponding database server. When viewed from the application program side, the database environment is completely unaware of the format in which it is recorded. Data updated by the master database server is updated using a common access language for updating. Only the protocol is sent to other servers. As a result, in database backup, data is duplicated in a plurality of different databases, and a plurality of backup data having different database structures are created. As a result, the backup operation conventionally performed becomes completely unnecessary.

Further, when a failure occurs in the database system which is normally the master database server, the next master database server (candidate) is selected in place of the master database server that has gone down, and the next master database server is selected. The data processing request to the database manager is also sent to another server using a common access language, and the client's database access changes to the next master database server. As described above, the switching from the master database server before the occurrence of the failure to the new master database server is performed, so that the conventional processing can be interrupted and the means for starting the recovery system can be omitted. However, in the event of a failure, the master database server that has taken over the operation in the form of a common access language journal records the data operations that occur while it is down, in case the failed database server recovers. When the downed master database server is restored, if the status of the downed master database is retained and operation can be resumed, it is possible to update to the latest database state using this common access language journal. it can. In other words, the database on each database server that constitutes the database backup system of the present invention can maintain the consistency of the contents by the common access language journal.

[0018]

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

FIG. 1 is a block diagram showing a configuration of a data processing system using a relational database according to one embodiment of the present invention.

As shown in FIG. 1, a plurality of databases 102, 104, and 106 and database servers 101, 103, and 10 corresponding to the databases 102, 104, and 106 are provided on the same network.
5 is connected. Here, the database 102 is a master database, and the corresponding database server 10
1 is a master database server. Further, the database servers 101, 103, and 105 are provided with database management systems 111, 113, and 115, which are software for managing the databases, and software 120 for transmitting and receiving a data manipulation language between the servers. This network can be a public line network or a local LA
The database server 105 operates in the Internet or intranet environment composed of N, for example, when the public network 107 is used, and the database server 105 is in a state of being locally dispersed. Further, a client / server type network is constructed as shown in the terminal 110, and data operations (search, update) are performed from the terminal 110 to the master database server 101.

Hereinafter, the operation of the database backup system will be described with reference to the flowchart of FIG.

First, a terminal (client) 110 sends a standard data manipulation language for performing data manipulation to the master database server 101, and requests data access (step 21). Here is JIS
/ SQL standard ISO (Structured)
Query Language) is used as a data manipulation language.

The master data server 101 receives an access request from the software 120 for transmitting the standard SQL, and stores the standard SQL in the database management system 11.
1 and analyze the contents (step 22).

As a result of the analysis, it is determined whether the request is a search process or a database update process of the corresponding database (step 23).

When a database search process is requested,
The master database 102 is accessed by the database management system 111, and the terminal (client) 11
The requested data is searched from 0 (Step 2)
4).

On the other hand, when a database update process is requested, the master database 102 is accessed by the database management system 111, and data requested by the terminal (client) 110 is updated (step 25).

However, since only the master database 102 actually performs the update process in response to the update request from the terminal (client) 110, it is necessary to further transmit the update request to another database server connected on the same network. As shown in FIG. 3, the standard SQL for update is distributed to another database server by the standard SQL transmission program 302 linked to the application program 301 of the communication interface (step 26).

The standard SQL transmitted thereafter is converted into a format that can be interpreted by the database management unit by a communication interface of another database server, that is, an application program that receives the standard SQL, and then converted to a database management system. The respective databases are updated by the same operation as the data update to the master database 102 (step 27). FIG. 4 shows the interface configuration of the receiving database server when the standard SQL is transmitted from the master database server 102 to another database server, in which the standard SQL is received and the program of the database management unit can be understood. Convert the received data to a format (S
QL daemon processing) program is incorporated.

An application program for accessing a database has the form shown in FIG. 5, and processing routines for a plurality of database management systems are linked to each other. This application program 5
01 is executed, the processing routine suitable for the database server to be connected operates, and the respective standard SQL is executed.
Create an environment that can execute The application only calls the common login / logout processing and the standard SQL issuing procedure, and has a structure that is not aware of the difference between the database systems.

Further, the update of the master database and the update of the other databases are processed asynchronously.

Finally, when the search and update processing is completed, the data management system 111 of the master database server 101 returns the treatment result to the terminal (client) 110 in the form of standard SQL (step 28).

The search / update processing when the database system is operating normally has been described above. Next, system switching when the database system goes down due to a failure or the like will be described with reference to FIGS. .

As shown in FIG. 6, a normal master database (server) 601 and other databases (servers) 602, 603, and 604 are connected on the same network as backup databases. However, each database management system is different. Here, if a failure occurs in the database system and the master database (server) 601 becomes unusable, the failure switching unit 108 in FIG. 1 selects a new master database (server) 702 shown in FIG. (Servers) 703 and 704 are backups. At the same time, the database (server) 70 to which the operation request from the terminal (client) 705 is also switched.
The access destination changes to 2. For example, in the case of an update request, the new master database (server) 702 transmits the update request to the databases (servers) 703 and 704 in the form of an update standard SQL by the standard SQL transmission program in the same manner as the master database normally performs. Send.
Database (server) 70 that received the standard SQL
3, 704 access their respective databases,
Perform update processing. Further, when a failure occurs, the data update record is saved while the other database server is down, in case the failed database server recovers. This record is called the SQL journal,
This is because when a terminal (client) 705 issues a database access request to the master database (server) 702, at the same time another database (server) 703,
The same request is sent to 704 in the form of an SQL journal. Then, when the downed database (server) 701 is restored, the state of the database at the time of the downtime is maintained and the processing can be resumed, the state of the database is updated based on the SQL journal. Updated and again master database (server)
It can be operated as

In the above-described embodiment, an example has been described in which an application program for requesting a database operation is operated on a database server. However, the application program may be operated in a client / server format from a terminal on a network. In the latter case, the application program of FIG. 3 is separated into a processing part on the terminal side and a processing part on the server side, and during that time, the synchronization processing is performed by a certain communication protocol.

In the search processing of the above-described embodiment, only the master database is accessed. The standard SQL used in the application program shown in FIG. 3 performs actual access to the master database management system.
When separated into those to be transferred to another database management system, the search, that is, the standard SQL of the reference system is not necessarily transferred, and thus omitted. However, similar to the update processing, the standard SQL is transferred to another database management system. May be.

Further, in the above embodiment, the processing result is returned to the terminal (client) in the form of the standard SQL. However, the result can be displayed on a screen or taken out by a form output or the like.

In the above-described embodiment, the database management unit has described the case where different system programs operate for each server. However, at least two or more different system programs may be installed on the same network.

[0038]

As described above, according to the present invention,
Since the database management system on each database server is a heterogeneous database system, the same phenomenon does not occur on other database servers even if a software failure occurs in the database management system on the master database. Conversely, if there is a bug in the software of a certain database management system, it can be found by comparison with another database, and the bug can be dealt with earlier.

Further, a standard data manipulation language (standard SQL)
It is easy to configure any number of database systems as a backup system as long as it is a database management system that can interpret the above, thereby increasing the availability of the system.

Further, since the backup data exists as a heterogeneous database by applying the standard data manipulation language, a special recovery process as in the related art becomes unnecessary.
By simply switching servers, data processing can be continued in the same state as before switching without interruption. As a result, operation time and cost can be reduced.

Further, since the hardware serving as the database server can be of a different kind,
In addition to increased availability in terms of hardware, the reliability of the entire system can be increased. In other words, a hardware failure unique to the master server is very unlikely to occur in another system, and there is almost no possibility that exactly the same hardware failure will occur at the same time.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an entire heterogeneous database management system according to the present invention.

FIG. 2 is a flowchart of data access according to an embodiment of the present invention.

FIG. 3 is a conceptual diagram for assigning a standard data manipulation language to various database management systems according to an embodiment of the present invention.

FIG. 4 is a conceptual diagram of a system for receiving a standard data manipulation language according to an embodiment of the present invention.

FIG. 5 is a conceptual diagram of an application program configuration for transferring a standard data manipulation language to a library for various database management units according to an embodiment of the present invention.

FIG. 6 is an explanatory diagram of an access route during normal operation of the system according to an embodiment of the present invention.

FIG. 7 is an explanatory diagram of an access route when a failure occurs in an operating master database server according to an embodiment of the present invention.

DESCRIPTION OF SYMBOLS 101, 103, 105 Database server 102, 104, 106 Database 107 Public line network 108 Failure switching unit 110 Terminal (client) 111, 113, 115 Database management unit 120 Communication interface 301 Communication interface application program 302 Standard SQL transmission program 501 Application program for database access 601 Master database system 602, 603, 604 Database system (backup) 605 Terminal (client) 702 Master database system 703, 704 Database system (backup) 705 Terminal (client)

Claims (5)

[Claims] A plurality of databases connected on a network; a database server corresponding to each of the databases; a database management unit existing in the database server for controlling the databases; One of different software is installed so that two or more types of software operate on the same network, and data is manipulated between the database management units using a common access language interpreted by the database management unit. A database backup system, comprising: a communication interface for passing a request. 2. A database management unit on the database server, wherein the database management unit on another database management unit on the same network
2. The database backup system according to claim 1, further comprising a common access language transmission program for simultaneously transmitting the common access language. 3. The database management unit on the database server accesses all other database management units on the same network simultaneously using the common access language, and updates the contents of each database. 2. The database backup system according to claim 1, wherein the contents of the databases on the same network are made consistent with each other. 4. In the event of a failure of the master database system, the master database server and the master database are separated from the processing, and the alternate master database server and the alternate master database are determined, so that the data processing is continued, and the separated master is recovered after the failure recovery. 2. The database backup system according to claim 1, further comprising a recovery function for incorporating the data server and the master database into the processing again as a master. 5. A database system comprising: a plurality of databases connected on a network; a database server corresponding to each of the databases; and a database management unit existing in the database server and controlling the database. The database management unit incorporates one of different software so that two or more types of software operate on the same network, and the database management unit of the master database server receives a data operation request from a client and responds. Operating a database, transmitting a data operation request to another database server using a common access language simultaneously with the operation of the database, and receiving the transmitted data operation request by the database server, data Operating the corresponding database by the base management unit.