JPH0511342B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] In a data processing system in which each system uses an inter-system shared resource exclusively, an exclusive request from a system that does not manage exclusive use information, when the exclusive use is impossible. By creating occupancy information for rendezvous from the occupancy information of the message and placing it on occupancy wait, wasteful repetition of exclusion requests is prevented and the load on the communication device is reduced.

[Industrial application field]

The present invention relates to a data processing system in which each system exclusively uses an intersystem shared resource such as a shared database, and in particular, an intersystem shared resource occupancy information management process that automatically generates occupancy information when it cannot be monopolized. It is related to the method.

When a database or the like is shared by multiple independent systems, exclusive control is required to prevent inconsistent data from occurring due to contention during data updates. It is desired to reduce the number of message communications for exclusive control and to enable efficient exclusive control.

[Conventional technology]

Multiple independent systems (processing units) for load balancing and fail-safe reliability
Processing of transactions is done by . In such a system, when using shared resources, especially when updating data, only one system uses the resources to prevent conflicting data from occurring due to contention with other systems. Exclusive control is required to enable exclusive use.

When using a shared resource that is required by the local system, if the shared resource is already in use, you can wait for the processing of the transaction using the shared resource to finish and then issue an exclusive request to use the resource. It will be possible to occupy the property. However, if the exclusive possession information is not managed, an opportunity to release possession cannot be grasped, and an exclusive request cannot be issued at an appropriate time.

Conventionally, in exclusive control between systems, only the system that receives a processing result for an exclusive request manages exclusive information.

[Problem that the invention seeks to solve]

According to the conventional method, a system that does not manage occupancy information cannot wait for occupancy because even if the result of an exclusive request is to add occupancy, the request cannot be restarted in the occupancy release process. . Therefore, there is a problem in that exclusive requests are made repeatedly, increasing the load on the communication device.

The present invention aims to solve the above-mentioned problems, and even if an exclusive request from a system that does not manage occupancy information becomes an occupancy load, it can automatically generate occupancy information.
The purpose is to provide a method that allows users to wait for occupancy.

[Means for solving problems]

FIG. 1 shows an example of the basic configuration of the present invention.

In FIG. 1, 10A to 10C are systems each having an independent CPU and memory, 11 is a communication path used for message communication between the systems, 12 is a shared resource such as a shared database, and 13 is a communication path used for message communication between the systems.
14 is an exclusion request receiving unit that receives an exclusive request requesting to occupy the shared resource 12; 14 is an exclusion request transmitting unit that sends an exclusive request message to another system; and 15 is a result for receiving and processing the result of the exclusive request. 16 is an occupancy information creation unit that creates occupancy information based on the information in the message when occupancy is added; 17 is an occupancy registration unit that registers and manages occupancy information; and 18 manages occupancy waiting. Represents the exclusive waiting management unit.

For example, in system 10A, shared resource 1
If there is an exclusive request to occupy 2,
The exclusive request receiving unit 13 accepts the request, determines whether or not occupancy is possible, and causes the exclusive request transmitting unit 14 to:
The request message is transmitted to other systems 10B and the like via the communication path 11.

As a result, when the result processing unit 15 is notified that occupancy is possible, the occupancy registration unit 17 registers occupancy information indicating that the transaction of the time system 10A occupies the shared resource 12,
Use shared resources 12.

When a notification that occupancy is not possible is received in response to an exclusive request, the occupancy information creation unit 16 adds occupancy information indicating which transaction in which system currently occupies the shared resource 12 to the received message. and registered by the occupancy registration unit 17. Then, the request source in the own system 10A is put into a held state, and the information is managed by the exclusive holding management section 18. When a transaction end notification is received, the exclusive use information is managed, so the exclusive release process can be executed, and the exclusive request transmitter 14 can retransmit the exclusive request in the waiting state.

Note that the same applies to the case where resources are shared by a plurality of other systems instead of the three systems.

[Effect]

FIG. 2 is a diagram for explaining the operation of the present invention. FIG. 2A shows a case in which occupancy is possible, and FIG. 2B shows a case in which occupancy is not possible.

Assume that the system 10A sends a message circulating an exclusive request to the system 10B regarding the resource α. As shown in FIG.
Immediately send the result message back to 0A. Thereby, the system 10A can register the occupancy information and use the resource α. For system 10C, system 10B has concluded that it can be occupied.
After that, a result message "α in use" is sent. Occupancy is determined, for example, by the majority logic of the system, including the own system 10A.
A result for a request is established if a majority of systems grant permission.

On the other hand, as shown in FIG. 2B, when an exclusive request for resource α is circulated and the system 10C becomes unable to occupy it, the system 10A automatically generates occupancy information regarding α from the message and registers it. do. This makes it possible to issue an exclusive request during exclusive release processing triggered by the completion of a transaction in another system.

As described above, when occupancy is not possible, occupancy information is automatically generated from the message and the occupancy wait state is created, so there is no need to issue unnecessary exclusive requests.

〔Example〕

FIG. 3 is a block diagram of an embodiment of the present invention, FIG. 4 is a diagram explaining the flow of exclusion processing according to an embodiment of the present invention, FIG. 5 is a diagram explaining processing of the result processing section, and FIG.
The figure shows an example of communication data of exclusive control information.

In FIG. 3, the same reference numerals as in FIG. 1 correspond to those shown in FIG. 20 is an exclusive data receiving unit that receives exclusive control information; 21 is a circulation processing unit that processes received circulation messages; 22 is a transaction completion processing unit that processes transaction completion messages; and 23 is a deadlock from other systems. A deadlock notification processing unit that processes notifications, 24 a transaction management unit of another system that manages transactions being executed in other systems, and 25 an occupancy check that checks whether or not a shared resource for which an exclusive request has been made can be occupied. 26 is an occupation release unit that releases the occupation, 27 is a transaction management unit that manages transactions in its own system, 28 is a deadlock detection processing unit that detects a deadlock based on exclusive possession information, and 29 is a deadlock detection processing unit that detects a deadlock based on the ownership information. 30 is an exclusive data transmitter that sends exclusive control information to other systems; 31 is a transaction end transmitter that notifies other systems of the end of a transaction; 32 is a deadlock. Represents a deadlock notification transmitter that notifies.

The flow of exclusive control will be described below with reference to FIGS. 3 and 4. (a) in the following explanation
-(j) correspond to (a) to (j) shown in the fourth section.

(a) Assume that an exclusive request is made in the originating system A. When the exclusive request accepting unit 13 receives the exclusive request, it calls the occupancy check unit 25. The occupancy inspection unit 25 performs occupancy determination control based on occupancy registration information.

(b) Determine whether the resource is an intersystem shared (global) resource. If it is a system-specific resource, exclusive processing is immediately executed. If the resource is a global resource, the exclusive request transmitter 14 executes exclusive request initiation processing.

(c) In the process of issuing an exclusive request, information on the resource to be occupied, transition information, etc. is notified to the other circulating destination system B by a circulating message.

(d) In the circulation destination system, the exclusive data receiving unit 20
When the circulation processing section 21 receives the circulation message, the occupancy inspection section 25 checks whether or not the system can be occupied, according to the occupancy registration information of its own system. The conclusion as to whether or not occupancy is possible is determined by majority logic. The overall amount of communication is reduced by producing results based on the consensus of a majority of systems, rather than the consensus of all systems.

(e) Here, if the request result is established, the initiating system A is notified of the result.

(f) Also, directly notify the result to the own system and perform the occupancy result reception process. That is, the exclusive registration unit 17 performs exclusive registration control. Alternatively, the exclusive waiting management unit 18 updates the waiting information.

(g) Result notifications are sent to other circulation destination systems C by piggybacking on other messages. In other words, instead of sending the results immediately when they are available,
You can save it in the buffer and send it in combination with other messages when the buffer is full. In the circulation destination system C that received this,
Performs reception processing of the occupancy request result.

(h) In the originating system A, when the result processing unit 15 receives the result message, it releases the wait state (WAIT) for the result of the occupancy request initiation process.

(i) Determine whether or not the resulting message can be possessed or not. If occupancy is possible, the occupancy registration unit 17 performs occupancy registration control.

(j) If occupancy is not possible, the occupancy wait management unit 18 performs occupancy wait registration control. By performing the registration of exclusive use wait, an opportunity to issue the next exclusive request can be obtained upon completion of the transaction. That is, the transaction management unit 24 of the other system activates the exclusive release unit 26, and releases the resources used by the transaction. As a result, the process for issuing an exclusive use request can be started again.

Next, the processing of the result processing unit 15 to which the present invention is particularly relevant will be explained with reference to FIG. Numbers ~ in the following description correspond to processes ~ shown in FIG.

Based on the result message, it is determined whether the result of the occupancy request is occupancy possible. If it cannot be occupied, control is transferred to processing.

If occupancy is possible, the task that requested occupancy is notified that occupancy is possible, and the result processing ends.

If occupancy is not possible, check whether the reason for occupancy is not set in the result message. For example, the requested resource may not be actually occupied by another system, but may simply be unavailable due to a lack of space or the like. In such a case, perform the following process. If a reason for not being accepted is set, execute the process.

Instructs the occupation requesting task to issue an occupation request again, and ends the result processing.

Determine whether or not the own system is managing a partner transaction that cannot be used. If it is not managed, the end of the transaction cannot be recognized, so control is transferred to the process and an instruction is given to issue an exclusive request again.

Checks whether the local system manages information that the requested resource is occupied by a non-occupiable partner transaction. If it is already managed, transfer control to processing.

Occupancy information such as which transaction occupies the requested resource is created from the received data in the result message. By performing this process, there is no need to immediately retransmit an exclusive request as in the conventional case, and exclusive waiting management can be performed.

Instructs the task that requested exclusive use to wait for exclusive use. When the possession of the other transaction is released, an instruction is given to issue a possession request.

FIG. 6 shows an example of communication data transmitted and received under exclusive control.

Communication data of exclusive control information such as a circulation message or a result message is composed of, for example, a message header section D1, an exclusive control header section D2, an exclusive message section D3, an exclusive request information section D4, and the like.

The message header section D1 indicates the message type, etc. In the exclusive control header section D2, header information for exclusive control is set, and transaction information, time information, etc. are stored. In the occupancy message section D3, the reason for non-occupancy is set in the result message. In the occupancy request information section D4,
Information such as requested resources is set in the circulation message.

〔Effect of the invention〕

As explained above, according to the present invention, when the result of an exclusive request is that occupancy is not possible, a system that does not manage occupancy information automatically generates and manages the occupancy information, so that the system automatically generates and manages the occupancy information. in,
The processing of the exclusion request can be restarted, and there is no need to repeat the communication of the exclusion request and the result of non-possession, so that the load on the communication device can be reduced.

For example, if the transaction processing time is 5 seconds and the exclusive request is retransmitted once every 0.1 seconds, communication will be performed a maximum of 50 times, but according to the present invention, 1 This means that unnecessary communications can be reduced.

[Brief explanation of the drawing]

FIG. 1 is an example of the basic configuration of the present invention, FIG. 2 is an explanatory diagram of the operation of the present invention, FIG. 3 is a block diagram of an embodiment of the present invention, and FIG. 4 is an illustration of exclusive processing according to an embodiment of the present invention. A diagram explaining the flow, FIG. 5 is a diagram explaining processing of the result processing section, and FIG. 6 shows an example of communication data of exclusive control information. In the figure, 10A, 10B, 10C are systems, 1
1 is a communication path, 12 is a shared resource, 13 is an exclusive request receiving unit, 14 is an exclusive request transmitting unit, 15 is a result processing unit, 16 is an occupation information creation unit, 17 is an exclusive registration unit,
18 represents an exclusive waiting management section.

Claims (1)

[Scope of Claims] 1. A system comprising a plurality of systems each having an independent processor, a shared resource shared among the plurality of systems, and a communication means for transmitting and receiving messages between the systems, and each of the systems is a data processing system having a processing means for notifying other related systems of the end of a transaction, which is a unit of processing data, wherein each system is configured to: transmit an exclusive request for a shared resource to another system; Means 14: In response to an exclusive request from another system, the own system checks whether or not the shared resource can be occupied based on the occupation information indicating which transaction in which system owns the shared resource, and determines whether the shared resource is possible or not. A method for transmitting a message notifying that exclusive use is not possible, and a method for determining which transaction in which system is executed based on the message notifying that exclusive use is not possible when a message indicating that exclusive use is not possible is notified in response to an exclusive request issued by the own system. occupancy information creation means 16 for creating occupancy information indicating whether the system occupies the shared resource; occupancy registration means 17 for registering and managing the created occupancy information within its own system; an exclusive use wait management means 18 for placing an exclusive request source in its own system in a waiting state and managing the information when the shared resource cannot be occupied due to a transaction termination notification; An inter-system shared resource occupancy information management processing method characterized in that an exclusive request to another system is retransmitted based on the wait state management information of the source of the exclusive request.