JP2001344141A - Distributed processing system provided with data backup function and its processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a distributed processing system provided with a data backup function and its processing method allowing a switch of a server for its connection for continuing processing even when a failure occurs in any server in the distributed processing system constructed of a plurality of servers and clients. SOLUTION: If a failure occurs in a server 12, a connection information changing part 20c in the client 20 changes a connection destination server information parameter set in a connection information management part 20b so as to set a server 14 as the connection destination. In this case, the database of the server 14 is updated so as to be equalized to that of the server 12, and the client 20 continues processing of the control object according to this database.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a plurality of servers,
The present invention relates to a distributed processing system having a data backup function including a plurality of clients connected to the respective servers and performing distributed processing of a control target, and a processing method thereof.

[0002]

2. Description of the Related Art Computer processing has been performed in various fields due to the recent development of information processing apparatuses and information processing techniques. For example, an online processing system in a financial institution or the like is well known. In this system, as a recovery measure in the event of a system failure, the system is completely duplicated, and one is a normal operation (working) system and the other is a standby standby system. If a failure occurs during operation, switch to the standby system,
It is considered to continue the service.

[0003] In this case, the data to be processed by the system and the database storing information required by the system for the processing so that the system can be switched from the active system to the standby system at any time are stored in the active system. If the contents of the active database are updated as a result of the processing set by each of the standby systems and executed by the active system,
Update the corresponding part of the standby database to the same content,
We operate to keep the contents of the database the same.

In order to maintain the database identity, the standby system simply stands by and does not execute any other processing. Therefore, the standby system is updated from the active system to the standby system. It is only necessary to transmit the data write processing to the database, and no processing such as contention control for database access is required.

In such an online processing system, although the system scale is large, the social impact of stopping the system due to a failure is enormous.
It is unavoidable that the burden of equipment costs due to the weight increase is unavoidable.

On the other hand, in a small-scale system such as an information processing system in a company, it is difficult to employ the above-described complete duplex system from the viewpoint of effective use of resources. In many cases, the standby system is also configured to execute another process different from the task processed by the active system.

In particular, in recent years, computers have been reduced in size and performance, and high-speed processors, large-capacity main memories, large-capacity hard disk drives, and the like have been mounted at low cost. As an information processing system, many clients are connected to multiple servers,
A distributed processing system in which processing in each client is distributedly controlled by each server is employed.

[0008] In such a small-scale system or a distributed processing system in a company, the contents of the database constructed in each server are kept the same, and the failure of the database constructed in any one of the servers is caused. In the event that a failure occurs, various database backup functions have been proposed that can restore the database of a failed server using the database of a normal server (Japanese Patent Application Laid-Open Nos. 7-114495 and 5-265829). Etc.).

For example, the distributed processing system shown in FIG.
A plurality of servers 1 and 2 and clients 3 and 4 are connected by a communication cable 5 such as a LAN. Each of the servers 1 and 2 has database storage units 6 and 7 for storing databases. The servers 1 and 2 are configured to process the processing requests of the clients 3 and 4 in a distributed manner.

[0010] Servers 1 and 2 and clients 3 and 4
Are server applications 1b stored according to the tasks to be processed by the distributed processing system,
2b and user applications 3a and 4a, and predetermined processing is performed by these applications 3a and 4a.

When the contents of the databases of the servers 1 and 2 are updated by the processing requests from the clients 3 and 4, each of the servers 1 and 2
Communication between servers is performed by a and 2a, and the updated content of each database is reflected on another database, thereby maintaining the same content of the databases.

In such a distributed processing system, if a failure that destroys the contents of the database of one server, for example, the server 2 occurs for some reason, the failure is performed using the contents of the database of the normal server 1. Can restore the contents of the database where the error occurred.

[0013] However, in the conventional distributed processing system, the contents of the database can be completely recovered. However, during this recovery processing, processing by a client connected to the failed server is temporarily stopped. Must be stopped. Therefore, a quick recovery system has been desired in order to minimize the influence on the system.

In particular, such a distributed processing system has 24
Control of machinery and equipment on production lines in manufacturing plants that require continuous operation over time (hereinafter referred to as process control)
In the case where the system is applied to, for example, production management work, if the system stoppage time required for the process of restoring a database failure is long, it greatly affects the maintenance of production efficiency.

On the other hand, in order to avoid a stop of the distributed processing system composed of a plurality of servers, the servers constantly monitor each other's status, and when any one of the servers fails, all functions are transferred to a normal server. A known cluster system is known.

However, the conventional cluster system is applied to an upper-level functional failure such as hardware and OS, and is not applied to a lower level such as a database. In addition, some time is required to check the status of each other's servers and to switch over when a failure occurs. Further, it is necessary to assign a plurality of communication addresses shared by a plurality of servers, and the cost increases accordingly.

When such a cluster system is applied to a production system, an OLTP (On-line Tr) in which processes such as updating, inserting, and deleting a database are performed critically.
In a production system that is an ansaction processing system, the entire system is stopped during server switching. Also, since the system is naturally restored when server switching is completed,
There is a need for a means to make the client aware of the failure. However, in the above-described cluster system, since a plurality of shared communication addresses are used, all of them are taken over by a normally operating server when a failure occurs, and the client monitors that the server has been migrated. It is very difficult to build a means.

[0018]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and in a distributed processing system including a plurality of servers and clients, a failure occurs in any one of the servers. Even if this happens, under the management of the client, a data backup function that can quickly switch the client connected to the failed server to a server without failure and connect to continue processing And a distributed processing system provided with the same.

[0019]

In order to achieve the above object, the present invention provides a distributed processing system comprising a plurality of servers and a plurality of clients connected to the respective servers and performing distributed processing of a control target. The server includes a database storage unit that stores a database that is updated by a process performed on the control target by the plurality of clients, and a data replication process that is performed based on the database update process performed by the client that processes the control target. A replication trigger generation unit that generates a trigger, an update information transfer unit that transfers update information of the database to another server based on the data replication trigger, and the database of the other server based on the transferred update information. A database update processing unit for updating, wherein each of the clients Comprising a connection information management unit for managing connection information of the connection destination server Ant is connected, and a connection information changer for changing the connection information of the connection destination server,
When a failure occurs in any of the plurality of servers, the connection information is changed by the connection information change unit, and the server is connected to the failed server under the management of the changed normal other server. The processing for the control target by the client that has been performed is continued.

The present invention also relates to a processing method in a distributed processing system comprising a plurality of servers and a plurality of clients connected to the respective servers and performing distributed processing of a control object, wherein the control method comprises controlling the plurality of clients. A first step of updating a database in accordance with a process for a target, a second step of generating a data replication trigger based on a process of updating the database by a process of the client for the control target, and a process of updating the database based on the data replication trigger. A third step of transferring update information to another server, a fourth step of updating the database of the other server based on the transferred update information, and a failure of any of the plurality of servers The client connected to the failed server The connection destination to the changes to the other normal servers under the management of the modified the other normal servers, characterized by continuing the processing for the control object by the client.

[0021]

FIG. 1 shows the configuration of a distributed processing system 10 to which the present invention is applied. In this distributed processing system 10, a plurality of servers 12, 14 and a plurality of clients 20, 22, 24, 26, 30, and 32 are connected to a LAN.
And the like.

When the distributed processing system 10 is operating normally, for example, the server 12 and the client 2
0, 22, 24, and 26 share processing of a process control system of a production line, for example, processing of controlling a manufacturing machine for producing a photographic film described later, and a server 14 and clients 30 and 32 execute production planning. , And is responsible for processing related to production management systems such as raw material management and inventory management.

The server 12 is a server for sharing the processing of the process control system, and the clients 20, 22, 24, 26
Database storage unit 122 for accumulating data such as production instruction information and production history information to be described later transmitted and received between
A backup processing unit 123 for backing up the contents of the database storage unit 122 online at regular time intervals and storing the backup data in the backup data storage unit 124;
An archive data creation unit 125 that creates archive data based on the update information of the database updated by the processes 4 and 26 and stores the archive data in the archive data storage unit 126, and a database update process by the clients 20, 22, 24, and 26 A replication trigger generation unit 132 that generates a data replication trigger based on the data replication trigger, and updates the database update information based on the data replication trigger to another server 14.
, And a database update processing unit 128 that updates data in the database storage unit 122 based on a database update processing request.

The archive data creation unit 125 creates archive data according to new update information after the backup of the database in the database storage unit 122 to the backup data storage unit 124. Before the start of backup, the archive data creation unit 125 creates archive data. 1
The archive data stored in 26 is discarded.
The time interval of the backup process to the backup data storage unit 124 can be arbitrarily set by the operator. For example, the period can be set to one day (24 hours). All the archive data from the start of the backup process to the start of the next backup process is accumulated in the archive data storage unit 126.
Further, the update information transfer unit 130 performs a process of transferring update information at fixed time intervals set by a system administrator.

The server 14 is a server for sharing processing of a production management system, and has a database storage unit 142 for storing data such as a production plan, raw material management, and inventory management created between the clients 30 and 32. In addition, a backup processing unit 143, a backup data storage unit 144, an archive data creation unit 145, an archive data storage unit 146, a database update processing unit 148, an update information transfer unit 150, and a replication trigger generation unit 152 configured similarly to the server 12. Having.

The clients 20, 22, 24, 26
Based on the production instruction information from the process management system server 12, the cutting machine 40, the winding machine 42, and the exterior machine 4 shown in FIG.
6. User applications 220, 222, 224, and 226 for controlling the packing machine 50 and transmitting manufacturing history information and the like collected from each device to the server 12.
It has. Similarly, the clients 30 and 32 include user applications 230 and 232 for processing operations such as production planning, raw material purchase management, and product inventory management with the production management server 14.

The cutting machine 40 controlled by the client 20 cuts a master roll, which is a photographic film material wound into a roll, into a predetermined width to produce a slit roll. The winding machine 42 controlled by the client 22 performs a process of winding the slit roll supplied from the cutting machine 40 into the cartridge case formed and assembled by the forming assembly machine 44. The exterior machine 46 controlled by the client 24 includes the small box supply device 4
A process for packaging the film cartridge with the small box supplied from 8 is performed. The packing machine 50 controlled by the client 26 performs a process of packing the film cartridge stored in the small box on the cardboard supplied from the cardboard supply device 52.

Servers 12, 14 and Client 2
Although 0, 22, 24, 26, 30, and 32 are not shown, in terms of hardware, similar to a general PC (personal computer), a processor, a main memory,
It consists of a hard disk, network interface, etc.
It operates under the control of the operating system installed on each server and client.

Next, the operation of the distributed processing system 10 during normal operation will be described with reference to FIG.

First, the client 20 receives the individual production instruction information from the server 12 of the process control system and displays it on the monitor screen. The same processing is performed in the other clients 22, 24, and 26 of the process control system.

The individual production instruction information is created by the clients 30 and 32 connected to the production management system server 14 and transmitted to the process control system server 12 via the server 14. Information from the process control clients 20, 22, 24, and 26 gathered in the server 12 is transmitted to the production management server 14.

The individual production instruction information transmitted from the server 12 to the client 20 includes a production roll number of a master roll serving as a photographic film material suitable for the type of product specified by the production plan data. From among the master rolls stored in the storage, a master roll with a corresponding production lot number is supplied to the cutting machine 40 by a self-propelled carrier or the like.

The client 20 sends the slitting conditions to the cutting machine 40, such as the transport speed of the master roll and the cutting machine 4
The setting data of the inspection condition by the surface inspection device provided in the area 0 is transmitted. The cutting machine 40 cuts the master roll into a certain width based on the operating conditions transmitted from the client 20, thereby producing a slit roll.

At this time, a plurality of slit rolls are manufactured from one master roll. To make it possible to identify the slit rolls in a later step, an emulsion number, a master roll manufacturing lot number, A label in which the slit roll number is printed with a bar code is created and affixed to each slit roll. This barcode is read by a barcode reader and input to the client 20.

Next, the slit roll is moved to the client 2
2 and is stored in a cartridge case.

Here, the individual production instruction information transmitted from the database storage unit 122 of the server 12 includes the emulsion number of the slit roll used for production, the production lot number of the master roll, and the slit roll number.

The winding machine 42 takes out the slit roll specified by the individual production instruction information from the storage and sets it. The bar code affixed to the set slit roll is read, and it is checked whether or not the slit roll corresponds to the designated slit roll.
Is transmitted to the server 12 via the. Then, the client 22 operates the winding machine 42 according to the conditions specified by the individual production instruction information from the server 12.

In the perforating section of the winding machine 42, perforation perforation is performed in accordance with the specified format. In the side print section, a latent image of product information is recorded. As the product information, an ID number (film ID number) using a barcode, a frame number, a product abbreviation, a manufacturer name, and the like are recorded. The film ID number is
The information is stored in the server 14 together with the order number of the production plan data, is transmitted to the server 12, and is also written in the production instruction information transmitted to the client 22 that controls the winding machine 42.

When the side print section prints the film ID number, this film ID number is fed back to the client 22 together with other side print information, and the film I number specified by the individual production instruction information is sent.
It is confirmed whether or not it matches the D number. The client 22 further transmits other information obtained so far, that is, the emulsion number, the production lot number of the master roll, the slit roll number, and the like to the server 12 in association with the film ID number. This information is stored in the server 12 and also transmitted to the production management server 14.

After the side print processing, the cutting section is operated to cut the long photographic film into a length corresponding to the number of frames that can be photographed, thereby producing a photographic film strip. The manufacturing conditions for operating the cutting unit are included in the individual production instruction information transmitted to the client 22 via the server 12 as before.

The long photographic film cut into a predetermined length is
It is transported to the winding section. A cartridge case formed and assembled by the forming and assembling machine 44 is supplied to the winding unit from a predetermined stacking unit in tray units. At this time, the tray ID number assigned to the tray is read and the client 2
2 to the server 12.

The server 12 stores the cartridge ID number of the cartridge case accommodated in the tray and the manufacturing history information in association with the tray ID number.
What kind of range of cartridge ID number the cartridge case supplied to the winder 42 has, as well as what order number the cartridge case is manufactured, and the parts of any manufacturing lot number Can be used to track and confirm information such as whether or not it is assembled.

When the cartridge cases are sequentially supplied to the winding section, the cartridge ID number is read by the bar code of the label, and the read cartridge ID number is read.
The number is immediately entered into the client 22.

The cartridge case at the reading position corresponds to a cartridge case in which the side print unit is combined with a photographic film strip to be subjected to the next side print. Therefore, the client 22 checks the cartridge ID number immediately before the side print unit performs the side print.

The cartridge ID number thus read is transmitted to the server 12, where the cartridge ID number is compared with the film ID number assigned to the photo filmstrip by side printing. As described above, the server 12 stores the film ID number and the cartridge ID number assigned to the product to be produced at the time of production planning data creation. Cartridge I
It is possible to identify whether the D number is appropriate.

The rear end of the photographic film strip is locked to the spool in the cartridge case by the operation of the winding section, and the spool is driven to wind the photographic film strip into the cartridge case. The product photo film cartridge is completed.

As described above, since the manufacturing history information of the photographic film strip such as the emulsion number, the master roll manufacturing lot number, and the slit number is already known, the manufacturing history information of the cartridge case and the photographic film strip is: The information is also stored as production management information in the production control system server 14 via the process control system server 12 in association with the cartridge ID number or the film ID number.

Further, the photographic film cartridge which has become a product through the winding section is stored in the stacking section in a state where the photographic film cartridge is stored in a tray capable of storing a predetermined number of the photographic film cartridges. At this time, tray I
The D number is read and transmitted to the client 22. The client 22 checks the ID number (cartridge I) of the photo film cartridge stored in the tray.
D number or film ID number usage record and missing number information,
Further, the production history information is correlated and fed back to the server 12. This information is also transmitted from the server 12 to the production management server 14.

As a result, information such as the ID number of the photo film cartridge stored in the stacking unit, the type of product, the manufacturing history of the photo film strip and the cartridge case can be grasped in association with the tray ID number.

The client 24 controls the exterior machine 46 and the small box supply device 48. Photo film cartridge
After being conveyed from the winding machine 42 to the exterior machine 44 and packed in a film case, it is stored in a small box.

For the film case, which production lot number of the P case is to be used is specified by the production instruction information instructed from the server 12, and the production lot number of the used film case is determined via the client 24 in the process. It is sent to the server 12 of the control system.

The small box is provided with a display indicating the type of product and a bar code. The bar code indicating the type of product is printed in advance at the time of manufacturing the small box, but the bar code indicating the packaging material ID number is used when the small box is supplied from the small box supply device 48 to the exterior machine 46. Printed.

The packaging material ID number to be printed is determined by the production management system server 14 when the production plan is created. Then, as in the case of the side print of the film ID number, after confirming that the cartridge ID number of the photographic film cartridge packaged therein matches the packaging material ID number transmitted as production instruction information, the packaging material ID is checked. The number is printed.

The photographic film cartridge packed in the small box is then transferred to a packing machine 50 controlled by the client 26. The packing machine 50 receives the supply of cardboard boxes for packing from the cardboard supply device 52, and packs, for example, 1000 photo film cartridges into cardboard boxes.

The packing unit prints a packing ID number as a bar code on the surface of the cardboard box when packing a predetermined number of products in the cardboard box. This packing ID number is determined by the server 14 of the production management system in the same manner as the above-mentioned packaging material ID number.
For each product, the packaging material I printed by the exterior machine 46
One package ID number is assigned to the usage range of the D number. The correspondence is stored in the server 14 of the production management system. Therefore, if the packing ID is read from the cardboard box, the use range of the packaging material ID number of the product packed therein can be grasped.

On the other hand, the clients 30 and 32 process operations such as creation of a production plan, purchase management of raw materials, and inventory management of products with the production management server 14. These clients 30 and 32 are operated by the workers in the production management department, and the above-described production instruction information is transmitted to the process management server 12 and collected and transmitted by the process management server 12. Product management data is created from the manufacturing history data of the product.

Next, the distributed processing operation will be described based on the system configuration of the clients 20 and 30 shown in FIG. Note that the same applies to the clients 22, 24, 26, and 28, and a description thereof will be omitted.

The client 20 has a process control unit 20 having a process control module for controlling the cutting machine 40 described above.
a, a connection information management unit 20b having a connection destination server information parameter as connection information, and a connection information change unit 20c having a connection destination server check module. Similarly, the client 30 checks the connection information, the production management unit 30a having the production management module for performing the production management process, the connection information management unit 30b having the connection destination server information parameter as the connection information, and checks if necessary. And a connection information change unit 30c having a connection destination server check module for performing a change process. Also, the servers 12, 1
4 are operation state information tables 122a and 142, respectively.
a.

When the distributed processing system 10 is in a normal operation state, the client 20
The client 30 is connected to the production management system server 14 and performs production management work. For this reason, the connection destination server information parameter of the client 20 specifies the connection destination server 12 by default, and specifies the production management system server 14 as the backup server. Conversely, the connection destination server information parameter of the client 30 specifies the connection destination server 14 by default, and the process control system server 12 as the backup server.

When the distributed processing system 10 is started, the connection destination server check module of the client 20 checks the server specified in the connection destination server information parameter (the server 12 specified first by default). That is, the connection destination server check module checks the operation state information table 122a of the server 12 specified by default, and establishes a connection if the server 12 is operating normally. The operation of the client 30 is the same.

If the server 12 is not in the normal operation state, the operation state information table 14 of the server (the server 14 in the case of the client 20) designated on the backup side is used.
2a is confirmed, and if the server 14 is operating normally, a connection is established. If both servers are not in normal operation status, it displays a connection error and stops.

When the connection is established, the connection information changing unit 20c
Notifies the process control module of the connection port information, thereafter periodically polls the operation status information table 122a of the connection destination server, and when the operation status of the connection destination server is stopped, the application on the client 20 side (Process control module) is automatically stopped. The operation of the client 30 is the same.

When one of the servers fails and stops for some reason while the distributed processing system 10 is operating in a normal state, the client 20 or 30 connected to the stopped server is operated as described above. To stop automatically.
For example, if the server 12 of the process control system is stopped due to a failure, the operator operates the client 20 that has been stopped, and the connection information change unit 20c changes the connection destination server information parameter from the server 12 set as the default to the backup side. Production management server 14 set as
Process to change the connection destination. Thereby, the connection destination server check module refers to the operation state information table 142a of the server 14 and establishes a connection with the server 14.

At this time, since the database storage unit 122 of the server 12 and the database storage unit 142 of the server 14 have the same contents, as described later, even if the client 20 is connected to the server 14, The control process can be continuously executed. The same applies when the server 14 is stopped due to a failure. Therefore, the film manufacturing process can be continued without any trouble even if one of the servers 12 and 14 has a failure.

Next, the backup operation during the normal operation of the distributed processing system 10 will be described with reference to the processing flowcharts of FIGS. 1, 4 and 5.

In the flowchart of FIG. 4, the result of processing by the clients 20, 22, 24, and 26 on the control target such as the cutting machine 40, or the result of processing by the operator, insertion, change, and deletion of the database in the database storage unit 122. When an update processing request such as the above is generated, the database update processing unit 128 of the server 12 sends an SQ indicating update information generated in accordance with the update processing request.
An L (Structured Query Language) is accepted (step S1). Then, whether this SQL is an update SQL for updating the database of its own database storage unit 122, or the database storage unit 142 of another server 14
Is determined to be a propagation SQL for updating the database (step S2).

If it is determined that the SQL is the update SQL, the database update processing unit 128 performs update processing such as insertion, change, and deletion of the database into the database storage unit 122 according to the content of the instruction of the SQL (Step S).
3) The copy trigger generation unit 132 is instructed to generate a copy trigger. Duplicate trigger generation unit 13 receiving the command
2 generates a replication trigger for replicating the database (step S4), and based on the replication trigger, makes the update SQL a propagation SQL and supplies it to the update information transfer unit 130 (step S5).

In the flowchart of FIG. 5, the update information transfer unit 130 performs polling at a fixed time interval (step S21), and when a propagation SQL is supplied from the duplication trigger generation unit 132 (step S22), the The SQL is updated to the database update processing unit 148 of the server 14.
(Step S23). Then, when the propagation SQL reception signal is received from the database update processing unit 148 (step S24), the propagation SQL of the update information transfer unit 130 is deleted (step S25).

On the other hand, in the flowchart of FIG. 4, the database update processing unit 148 of the server 14 determines whether the SQL received in step S1 is an update SQL generated in the clients 30 and 32 or not. SQL is determined (Step S
2).

If the propagation SQL is determined, the database update processing unit 148 determines whether the update information of the propagation SQL is an insertion (step S6), a change (step S7), or a deletion (step S8). ) Is determined. Further, it is determined whether or not each change information has data (steps S9, S10, S11). In addition,
If there is no data, error processing is performed on the assumption that a transfer failure has occurred (step S12).

All the propagation SQLs transferred through the above processing
Is performed (step S13), the database of the database storage unit 142 is updated (step S13).
3). In this case, the database update processing unit 148 issues a replication trigger generation prohibition instruction to the replication trigger generation unit 152. Therefore, by the occurrence prohibition command, it is possible to prohibit the update information transfer unit 150 from transmitting update information based on the propagation SQL to the server 12.

As described above, the servers 12 and 14
Of the database storage units 122 and 142 are maintained the same, though asynchronously.

In the asynchronous distributed processing system,
Although there is a problem of data competition, the distributed processing system 10 of the present embodiment clearly distinguishes the functions of the production management system and the process control system for each connection destination database in a normal operation state. Insertion, update and deletion of data issued from the client connected to
Data is not inserted, updated, or deleted in the same record by the QL and the propagation SQL, so that data conflict can be prevented.

On the other hand, the backup processing units 123 and 143 of the servers 12 and 14 store the database storage units 122 and 1 at fixed time intervals such as in units of one day (24 hours).
42 is stored in the backup data storage unit 12 during operation.
4, 144, and the database storage units 122, 1
42 backup data is created. This backup operation includes a full backup method in which all data contained in the database storage units 122 and 142 are backed up at one time, and only files whose data has been updated after the last full backup or newly created data. Differential backup methods for backing up data, incremental backup methods for backing up only files whose data has been updated since the last full backup or differential backup, and newly created data are known, and these backup methods are known. The backup data storage units 124 and 144 are created using any one of the above.

In this case, the archive data creation unit 12
5 and 145, at the timing when the creation of the backup data is started, discard the contents of the archive data storage units 126 and 146 that have accumulated the update information of the database up to that time, and generate the data in the database storage units 122 and 142 after this timing. The content of the new update process is stored as archive data in the archive data storage units 126, 1
The work to record in 46 is started.

Here, the backup data storage unit 12
The operation of backing up the database to 4, 146 is performed using the file copy function of the servers 12, 14 at the OS level. The backup by the file copy function is performed by the database storage unit 122, 1
Unlike the above-described operation using the export function in which the structure information and the data themselves are converted into different formats and output to a file, the database is copied in its original format, and although a large hard disk resource is required, There is an advantage that the time required for backup is short.

For example, in the backup of a database having a data amount of 3 gigabytes, the backup by the export function takes about 600 minutes, while the backup by the file copy function takes about one-tenth of the time, ie, about 60 minutes. can do. However, when the backup data is created by the file copy function, it is necessary that the files in the database storage units 122 and 142 and the data in the backup data storage units 124 and 144 have completely the same settings and file names. is there.

With the above configuration, backup data is created while the servers 12 and 14 are running, and new update information for the database storage units 122 and 142 after the start of backup data creation is stored in the archive data storage unit 126. , 146, and efficiently and quickly in the database storage units 122, 1
42 backups can be performed. Further, as described later, when a failure such as the content of one database is destroyed, the content of the database can be quickly restored using the backup data and the archive data.

Next, a data recovery method when a failure occurs in which the content of the database storage unit 142 of the server 14 is destroyed will be described.

In this case, the clients 30 and 32 connected to the server 14 switch the connection destination to the server 12 and operate the distributed processing system 10 by the server 12 alone. This allows you to stop the system
Production can be continued. Next, a recovery operation on the hardware of the failed server 14 is performed. For example, replacement of a hard disk as the database storage unit 142 is performed.

After performing the above processing, the contents of the backup data storage unit 124 of the server 12 are restored (file copied) to the database storage unit 142 of the server 14. By this operation, the database storage unit 1
A copy of the database identical to the contents at the time of backup of No. 22 is constructed in the database storage unit 142. During this process, the archive data storage unit 126 of the server 12 records the archive data since the start of the backup during operation.

The operation of restoring the contents of the backup data storage unit 124 to the database storage unit 142 of the server 14 is performed by using the file copy function as described above. Therefore, each server 1
The databases of the database storage units 122 and 142 are completely identical, including the settings, are placed on the hard disk drive of the same name, and are connected to the server when one server fails. It is necessary to set a different global name for external access in order to take over the processing of the client that has been performed.

Next, after the backup data copy processing is completed, the operation of all the clients 20, 22, 24, 26, 30, 32 connected to the server 12 is performed so that the database storage unit 122 is not updated. Is temporarily stopped. In this state, the contents of the archive data stored in the archive data storage unit 126 of the server 12 are applied (written) to the database storage unit 142 of the server 14.
I do. This write operation is automatically performed by a so-called roll-forward process. This roll-forward function is provided by being incorporated in general database processing software. Storage units 122 and 142
Is restored to the same content.

After the above recovery work is completed, the clients 30 and 32 are connected to the server 14 again, and
Restarting the distributed processing systems 1 and 2
0 operation is resumed.

Here, the time when the distributed processing system 10 is completely stopped is only while the archive data excluding the backup data is applied to the database.
For example, if the time interval of the backup during operation is set to one day, the amount of the archive data is 1 at a maximum.
This is the amount of database updates for the day. The time required to restore the database from the archive data is several minutes to several tens of minutes, and therefore, the time during which the distributed processing system 10 is stopped can be reduced to this level. System stoppage time can be greatly reduced as compared with the time required for (8 hours).

[0086]

As described above, according to the present invention, in a distributed processing system composed of a plurality of servers and clients, even if a failure occurs in any one of the servers, management on the client side is possible. , The server can be quickly switched to another normally operating server and connected to continue processing. As a result, the productivity of the system can be suitably maintained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a distributed processing system according to the present invention.

FIG. 2 is a block diagram showing a configuration when a distributed processing system according to the present invention is applied to a production line.

FIG. 3 is a connection control block diagram of a client in the distributed processing system according to the present invention.

FIG. 4 is a flowchart showing a processing procedure in a database update processing unit in the distributed processing system according to the present invention.

FIG. 5 is a flowchart showing a processing procedure in an update information transfer unit in the distributed processing system according to the present invention.

FIG. 6 is a block diagram showing a configuration of a conventional distributed processing system.

[Explanation of symbols]

 Reference Signs List 10 distributed processing system 12, 14 server 20, 22, 24, 26, 30, 32 client 20a process control unit 20b, 30b connection information management unit 20c, 30c connection information change unit 30a production management unit 122 , 142 ... database storage units 123, 143 ... backup processing units 124, 144 ... backup data storage units 125, 145 ... archive data creation units 126, 146 ... archive data storage units 128, 148 ... database update processing units 130, 150 ... updates Information transfer units 132, 152 ... duplication trigger generation unit

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Claims (5)

[Claims] 1. A distributed processing system comprising: a plurality of servers; and a plurality of clients connected to the respective servers and performing distributed processing of a control target, wherein each of the servers is configured to control a plurality of clients for the control target. A database storage unit that stores a database that is updated by processing; a replication trigger generation unit that generates a data replication trigger based on an update process of the database by a process on the control target of the client; An update information transfer unit that transfers update information of a database to another server; and a database update processing unit that updates the database of the other server based on the transferred update information. Manages the connection information of the connection destination server to which the client is connected A connection information management unit, and a connection information change unit that changes the connection information of the connection destination server. When a failure occurs in any of the plurality of servers, the connection information change unit stores the connection information. A data backup function characterized by continuing processing on the control target by the client connected to the failed server under the management of the changed normal other server. Distributed processing system. 2. The system according to claim 1, wherein the plurality of servers include a server that manages a client of the production control system to be controlled and a server that manages a client of the process control system to be controlled. A distributed processing system having a data backup function. 3. The system according to claim 2, wherein each of the servers has a distributed processing function independently set, and is capable of independently processing the database in each of data insertion, update, and deletion operations. Distributed processing system with a data backup function. 4. A processing method in a distributed processing system comprising a plurality of servers and a plurality of clients connected to the respective servers and performing distributed processing of a control target, wherein the plurality of clients perform processing of the control target in accordance with processing of the control target. A first step of updating a database; a second step of generating a data replication trigger based on an update process of the database by a process on the control target of the client; and updating the update information of the database based on the data replication trigger. A third step of transferring the database to another server, a fourth step of updating the database of the other server based on the transferred update information, and when a failure occurs in any of the plurality of servers, the failure The connection destination of the client connected to the server Processing in a distributed processing system having a data backup function, wherein the processing is changed to another normal server and processing of the control target by the client is continued under the management of the changed normal other server. Method. 5. The method according to claim 4, wherein when returning to a normal operation after the restoration processing of the failed server, all the clients are disconnected from the server and the connections of the clients are disconnected. After resetting the information, the client is connected to the server in accordance with the set information, and a process for the control target is resumed in a normal connection state. Processing method of distributed processing system.