JP3039456B2 - Task management system, task management method, and storage medium storing task management program - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a task management system, a task management method, and a storage medium storing a task management program used in a computer system realizing multitask processing, and more particularly, to control activation of a task in batch processing. The present invention relates to a task management system, a task management method, and a storage medium storing a task management program, which can avoid occurrence of a deadlock error.

[0002]

2. Description of the Related Art In a computer system that realizes multitasking, a plurality of child tasks that simultaneously execute a plurality of processes are managed by a parent task. In a batch process by such a computer system, when a plurality of child tasks refer to or update a common master file, a deadlock error may occur depending on the timing of accessing the master file.

Normally, when a batch process ends abnormally due to a deadlock error, it can be recovered by re-executing a transaction as a standard function of the operating system. However, when the batch processing executes a large amount of processing for a large-scale master file, forcibly writing out each transaction requires a great deal of processing time, so that the transaction is re-executed when a deadlock occurs. That was impossible.

[0004] Therefore, when a batch process requesting a large amount of processing for a large-scale master file ends abnormally due to a deadlock error, the batch process has to be restored by restarting it. But,
Simply restarting the batch process will cause the same child task to access the master file at the same time as the previous execution of the batch process, causing a deadlock error during the previous execution. There was a possibility that a deadlock error would repeatedly occur in the same place.

[0005]

As described above, when a batch process requesting a large amount of processing for a large-scale master file ends abnormally due to a deadlock error, the batch process is restored by restarting the batch process. However, in the past, the restart was performed in the same procedure as when the batch process was executed when a deadlock error occurred, so the disadvantage that the same deadlock error is likely to occur again is high. there were.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and a task management system, a task management method, and a task management method for avoiding the occurrence of the same deadlock error in the reprocessing of batch processing abnormally terminated due to a deadlock error It is an object to provide a storage medium storing a management program.

[0007]

A task management system according to the present invention that achieves the above object realizes a multitask process including a child task for executing batch processing and a parent task for managing the child task. In the task management system used in the above, the parent task monitors the execution state of processing by the child task, and acquires child task end state acquisition means for acquiring information on the end state of the child task that has completed processing. At the time of activation, regarding the child task necessary for executing the batch processing, the information regarding the end state of the child task obtained by the child task end state obtaining means is referred to, and the batch processing is determined to be a deadlock error. The child task that caused the deadlock error earlier than the other child tasks Characterized in that a starting child task activation means grayed.

As a result, the batch processing becomes deadlocked.
If the batch processing is restarted due to an error, if the batch processing is restarted, the processing by the child task will be executed at a different timing from the time when the error occurred, so the child task will generate a deadlock error again at the same timing I will not do it. Also, in order to automatically shift the start timing of the child task on condition that the end of the previous batch process is abnormal end, the operator does not need to be aware of the previous end state in the batch process, and Can be activated.

According to a second aspect of the present invention, the task management system further includes a timer for setting an interval time for controlling the activation timing of the child task, wherein the child task activation means of the parent task is provided with the dead task. Activate the child task in which the lock error has occurred, start the timing by the timing means, and activate the remaining child tasks when the time interval set in advance by the timing of the timing means has been reached. It is characterized by the following.

[0010] The task of the present invention for achieving the above object is also provided.
The task management method includes a child task for executing batch processing and the child task.
Perform multi-task processing including parent tasks that manage
In the task management method of the computer system that appeared
Therefore, the processing by the parent task is
Activating the required child task in response to the
Managing the execution of processing by child tasks.
The child task management step is performed by the child task.
The step of monitoring the execution state of the process, and the process has been completed
Obtaining information about the exit status of the child task;
Wherein the child task activation step initiates batch processing.
Required to execute the batch process.
The task is retrieved by the child task end status acquisition means.
Refers to the obtained information on the end state of the child task
Step and the batch process to be started are dead
If an abnormal termination has occurred due to a lock error,
A step that starts the child task that generated the
And the child task that caused the deadlock error
After starting, start other child tasks at predetermined timing
And performing the steps of:

According to a fourth aspect of the present invention, there is provided the task management method according to the first aspect.
When the notifier task start step starts batch processing
Related to the child tasks required to execute the batch processing.
And obtained by the child task end state obtaining means.
A step of referring to information on an end state of the child task
And the batch process to be started is deadlocked
The deadlock when abnormal termination due to an error
・ Start the child task that generated the error, and
Step to start timing the specified interval time
When the interval time is reached, another child task
Activating the network .

Further, according to the present invention, which achieves the above objects,
Storage medium that stores a task management program that performs disk management
The body manages the child tasks that perform batch processing and the child tasks.
That realize multitask processing including the parent task
Tasks that control computer systems and perform task management
In the storage medium storing the management program, the task
By the parent task realized by the
The child task that is required for the batch process to be executed
Launching the task and executing the process by the child task.
Managing the rows.
Monitors the execution status of the process by the child task
Regarding the step and the end status of the child task that has finished processing
Acquiring child information.
When the step invokes a batch process, the batch process
For the child tasks required to perform the
Of the child task acquired by the task termination status acquisition means
Referring to information on the status;
Batch processing to be attempted is abnormal due to deadlock error
If the deadlock error occurs,
Launching a child task that has
After launching the child task that generated the error,
Activating another child task in the event that the child task starts .

[0013]

[0014]

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

FIG. 1 is a block diagram showing a configuration of a task management system according to one embodiment of the present invention.

Referring to FIG. 1, the task management system according to the present embodiment includes a child task end state acquiring unit 10 for monitoring the execution state of a batch process and acquiring information on the child task end state, A management file 20 for storing information on the end state of the child task acquired by the acquisition means 10, and a child task activation means 30 for controlling the activation of the child task as necessary by referring to the management file 20 when the batch processing is activated And a system timer 40 used to control the activation of the child task. In the above configuration, the child task end state acquisition means 10 and the child task activation means 30 are realized as functions of a parent task that manages child tasks. The storage medium 50 stores a computer program for controlling the operation of the task management system.

FIG. 2 shows a flow of the operation of managing the child task by the parent task when executing the batch processing. As shown in the figure, when starting a batch process, the child task starting unit 30 of the parent task first refers to the management file 20 to check whether information regarding the batch process is stored (step 201). Here, the information on the batch processing is information indicating whether the batch processing has abnormally terminated due to a deadlock error or other failure in a child task, and specifies the child task (failed task) when the batch processing has abnormally terminated. Information. If no information about the abnormal termination is stored, the necessary child task is started as usual (steps 202 and 203). On the other hand, if information indicating that the batch process has been abnormally terminated due to the occurrence of a deadlock error at the time of the previous execution is stored, first, the failed task is activated (step 202,
204) Then, start another child task (step 2)
05). The detailed activation procedure in this case will be described later.

Next, the parent task monitors the execution state of the processing by the child task (step 206), and waits for the termination of the processing by the child task (step 207). When the processing by the child task ends and the child task notifies the parent task of information about the end state, the parent task end state acquisition unit 10
Stores the received information in the management file 20 together with the information specifying the child task (steps 207 and 207).
8).

FIG. 3 shows the management of the operation of the child task by the parent task in detail. As shown in the figure, when a parent task activates a child task necessary for executing batch processing (step 301), the child task starts business processing under the management of the parent task (step 311). The parent task monitors the execution state of the child task (step 302). When the child task ends the business process (step 312), the child task notifies the parent task of the end state, that is, whether the process has been completed normally or abnormally (step 313). Child task end state acquisition means 10 of the parent task that has received the end state notification
(Step 303), the acquired end state is stored in the management file 20 (Step 304). Here, if the child task ends abnormally due to a deadlock error, all child tasks related to the batch processing are forcibly ended thereafter in order to perform recovery by restarting (step 305).

More specifically, referring to FIG. 5, in batch processing in which m child tasks of tasks T-1 to T-m access common master files M-1 and M-2, When T−n (n: 1 ≦ n ≦ m) generates a deadlock error, the parent task
-N is stored in the management file 20 to indicate that it has terminated abnormally due to a deadlock error, and other tasks T-
1 to T- (n-1) and T- (n + 1) to T-m are forcibly terminated.

FIG. 4 shows in detail the child task starting operation by the child task starting means 30 of the parent task at the time of starting the batch processing. This processing is performed in step 201 shown in FIG.
To step 205. As shown,
The child task activation means 30 refers to the management file 20 at the beginning of the activation of the batch processing (Step 401). If the information regarding the abnormal end of the batch processing is not stored in the management file 20, the necessary child task is activated as usual (steps 402 and 403).

On the other hand, if the management file 20 stores information indicating that the batch process was abnormally terminated due to a deadlock error in the previous execution, the current activation is a restart after the abnormal termination. Since it is recognized that there is a child task (abnormal task), information for identifying the abnormally ended child task (failed task) is obtained (steps 402 and 404). Then, the system timer 40 is started (step 40).
5), start the failed task (step 406). As a result, the failed task starts business processing prior to other child tasks (step 411).

After the system timer 40 is started under the control of the parent task, it notifies the parent task when a preset interval time has been reached.

When the child task activation means 30 of the parent task receives a notification indicating that the interval time has been reached from the system timer 40 (step 407), it activates the remaining child tasks (step 408). As a result, the child task that did not generate a deadlock error in the previous execution of the batch processing starts the business after the elapse of the interval time since the failed task started the business processing (step 421). .

Referring to the example of FIG. 5, the parent task refers to the management file 20 and recognizes that the task T-n has caused a deadlock error, and the failure task T-
n is activated prior to other tasks, and the remaining tasks T-1 to T- (n-1), T-
Activate (n + 1) to T-m.

As described above, when the batch processing is abnormally terminated due to the deadlock error, and the batch processing is restarted, the child task in which the deadlock error occurred in the previous execution is replaced with another child task. In this case, the child task does not generate a deadlock error again at the same timing in the same processing. Further, as described above, the management file 20 is referred to when the batch processing is started, and on the condition that the information regarding the abnormal termination in the batch processing is stored.
Since the start timing of the child task is automatically shifted, the operator can start the batch process without being conscious of the previous end state of the batch process.

As shown in FIG. 1, the computer program for realizing the function of the parent task in the present embodiment includes a magnetic disk, a semiconductor memory, and other storage media 5.
0 and provided. Then, the computer program is loaded into the internal memory of the task management system and the CPU is controlled, thereby realizing the function of the parent task described above.

[0028]

Next, the task management system according to this embodiment will be described in more detail with reference to examples.

In the task management system of this embodiment shown in FIG. 3, eight child tasks of tasks TS01 to TS08 are managed under a parent task, and eight master files A to H are used in batch processing. Further, in the batch processing described below, the tasks TS01 to TS08 randomly access the master files A to H to refer to and update data. Note that the master files A to H are large-scale master files and do not perform forced writing for each transaction. Further, in the batch processing, it is assumed that there is a processing in which the task TS02 and the task TS03 alternately update the same record of the master file C and the master file D.

First, business processing by the task TS02 and the task TS03 and management by the parent task will be described with reference to FIG. As described above, the task TS02 and the task TS03 update common resources. That is, as shown in FIG. 7, task TS02 acquires and locks record X stored in master file C, and task TS03 records record X stored in master file D.
Get and lock. Next, the task TS02 tries to acquire the record Y, but is locked by the task TS03, so that it is in a state of waiting for unlocking.
When the task TS03 tries to acquire the record X, the task TS02 and the task TS03 lock mutually requested records, and a deadlock occurs. Then, the task TS03 ends, and the child task end state acquisition means 10 of the parent task returns the task TS03.
03 is written to the management file 20 to indicate that it has been terminated by deadlock. Further, the parent task forcibly ends other child tasks including the task TS02.

Next, the operation of restarting the batch processing will be described with reference to FIG. The child task activation means 30 of the parent task first restores the master files A to H as a preliminary operation, and then refers to the management file 20.
Since the management file 20 stores information indicating that the task TS03 has been completed due to the deadlock, the child task activation unit 30 activates the system timer 40 to activate the task TS03. As a result, the task TS03 acquires the record X from the master file C, acquires the record Y from the master file D, and executes the business process. Next, the child task activation means 30
Upon receiving a notification from the system timer 40 that the interval time has elapsed, the remaining child tasks including the task TS02 are started. Thereby, the task TS
02 acquires record X from master file C,
Since the activation timing is different from the activation timing of the task TS03, no deadlock occurs.

Although the present invention has been described with reference to the preferred embodiments, the present invention is not necessarily limited to the above embodiments. Even if the start timing of the child task is shifted as described above, a deadlock error may occur in the processing of another child task, but after the deadlock error has occurred at least once. Can avoid deadlock errors in the same processing at the same timing, so that it is possible to approach deadlock failure completely.

[0033]

As described above, the task management system, the task management method, and the storage medium storing the task management program according to the present invention provide a multitasking computer system in which batch processing is performed due to the occurrence of a deadlock error. In a case where recovery is attempted by restarting the batch processing after abnormal termination, the task in which the deadlock error has occurred is started earlier than other tasks. Therefore, since the process is executed at a timing different from the case where the deadlock error has occurred, the recurrence of the deadlock error can be prevented.

In addition, since the transaction is restored by restarting the batch process instead of re-executing the transaction when a deadlock occurs as described above, the batch process requires a large amount of data for a large master file in the computer system. Thus, there is an effect that the recovery can be performed without any problem even when the above process is involved.

Further, upon abnormal termination of the batch processing,
Since the end state is written in the management file before the end, the batch state can be recognized and the batch processing can be appropriately started when the batch processing is restarted. As a result, since the execution state of the business process can be taken over, the operator does not need to be aware of the previous end state,
There is an effect that the batch processing can be started again.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a task management system according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of a management operation of a child task by a parent task in the present embodiment.

FIG. 3 is a flowchart showing in detail the management of the operation of the child task by the parent task in the embodiment.

FIG. 4 is a flowchart showing in detail a child task activation operation by a parent task in the embodiment.

FIG. 5 is an explanatory diagram showing a specific operation example of the task management system according to the embodiment;

FIG. 6 is a block diagram showing a configuration of a task management system according to a specific embodiment of the present invention.

FIG. 7 is an explanatory diagram showing an operation when a deadlock error occurs in the task management system according to the embodiment.

FIG. 8 is an explanatory diagram illustrating a child task activation operation in the task management system according to the present embodiment.

[Explanation of symbols]

 Reference Signs List 10 child task end status acquisition means 20 management file 30 child task activation means 40 system timer

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Claims (6)

(57) [Claims] 1. A task management system used in a computer system that realizes multitask processing including a child task that executes a batch process and a parent task that manages the child task, wherein the parent task is processed by the child task. Child task end status acquisition means for monitoring the execution status of the child task and acquiring information on the end status of the child task that has completed the processing, and regarding the child task necessary to execute the batch process when starting the batch process And referring to the information on the end state of the child task obtained by the child task end state obtaining means, and when the batch processing has abnormally ended due to the deadlock error, the child which has generated the deadlock error A task launching means for launching a task at a timing earlier than other child tasks. Management system. 2. The child task activation means of the parent task further activates the child task in which the deadlock error has occurred, further comprising a timer for setting an interval time for controlling the activation timing of the child task. 2. The timer according to claim 1, further comprising: starting timing by the timing means; and activating the remaining child tasks when the interval time set in advance by the timing of the timing means has been reached. Task management system. 3. A task management method for a computer system that realizes a multitask process including a child task for executing a batch process and a parent task for managing the child task, wherein the process by the parent task is performed in the batch process to be executed. Activating the necessary child task, and managing the execution of the process by the child task, wherein the child task management step monitors an execution state of the process by the child task; Acquiring the information on the end state of the child task that has completed the processing. The child task activation step includes the steps of: starting a batch process, for the child task necessary to execute the batch process; Referring to information on the end state of the child task obtained by the task end state obtaining means; If the batch process to be started is abnormally terminated due to the occurrence of a deadlock error, a step of starting the child task that has generated the deadlock error; and starting the child task that has generated the deadlock error. Activating another child task at a predetermined timing after the execution. 4. The child task activating step, when a batch process is activated, terminates the child task acquired by the child task termination status acquiring means with respect to a child task required to execute the batch process. Referencing information about a state; and, when the batch process to be started has been abnormally terminated due to a deadlock error, activating a child task in which the deadlock error has occurred, and a preset interval. 4. The method according to claim 3 , further comprising: starting time counting; and activating another child task when the interval time is reached.
The described task management method. 5. A storage medium storing a task management program for performing a task management by controlling a computer system implementing a multitask process including a child task for executing a batch process and a parent task for managing the child task, The processing by the parent task realized by the task management program includes a step of activating the necessary child task in accordance with a batch process to be executed, and a step of managing execution of the processing by the child task. The task management step includes a step of monitoring an execution state of processing by the child task, and a step of acquiring information on the end state of the child task that has completed processing, and the child task activation step activates batch processing. In doing so, regarding the child tasks necessary to execute the batch processing, the child tasks are terminated. Referring to information about the end state of the child task obtained by the end state obtaining means; and, if the batch process to be started has abnormally ended due to occurrence of a deadlock error, the deadlock error Activating a child task that has caused the deadlock error, and activating another child task at a predetermined timing after activating the child task that has generated the deadlock error. The storage medium in which it was stored. 6. A child task activating state in the task management program stored in the storage medium, wherein, when a batch process is activated, a child task necessary for executing the batch process is set in the child task end state. A step of referring to information on an end state of the child task obtained by the obtaining unit; and a step of generating the deadlock error when the batch process to be started is abnormally ended due to a deadlock error. The method according to claim 5, further comprising: starting a task and starting timing of a preset interval time; and starting another child task when the interval time is reached.
A storage medium storing the described task management program.