JPH0456341B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an inter-task queue control method in online task processing.

[Technical Background of the Invention] Generally, when constructing an online system, in order to improve response performance and establish a module configuration, processing is divided into processing tasks for each function (in the example shown in Fig. 4), as shown in Fig. 4. , tasks A, B, and C). Processing requests (inter-task queues,
That is, inter-task queues (hereinafter referred to as inter-task QUEs) are transferred and processed.

As shown in Figure 5, the inter-task QUE
The QUE entry is created in a free QUE entry in the QUE entry pool 14 secured in the main storage device 13 of the computer main body 12 having 11. This is called generation of an inter-task queue entry (QUE entry). FIG. 5 shows a state in which QUE entries 15 to 17 for task A and QUE entry 18 for task B are generated. QUE entry 15-1
8 has inter-task queue information (hereinafter referred to as QUE information) passed to the corresponding task. QUE information is retrieved in the order of input based on a first-in, first-out method.

Therefore, in order to implement the first-in, first-out method, a queue control table 20 for managing QUE entries for each task is secured in the main storage device 13, as shown in FIG.
In the queue control table 20, control entries specific to each task are prepared. In FIG. 5, a control entry 21 for task A and a control entry 22 for task B are shown. control entry 2
1 and 22 contain all QUEs belonging to the relevant task.
A first entry pointer indicating the position of the first entry among the entries and a last entry pointer indicating the position of the last entry are set. Therefore, the first entry pointer indicates the next QUE entry to be retrieved in the task, and the last entry pointer indicates the newly generated QUE entry.
A QUE entry to be connected (linked) to the entry is required. Also, QUE entries 15 to 18
A next entry pointer indicating the position of the QUE entry to be processed next to the same entry is set in (However, since QUE entries 17 and 18 are the final QUE entries for tasks A and B, 0 is set as the next entry pointer. ) each belonging to the same task
QUE entries are linked in the order they are entered.

Therefore, depending on the contents of the queue control table 20 and the QUE entry pool 14 secured in the main storage device 13, the retrieval and processing of each QUE information and the creation and deletion of QUE entries can be executed correctly. However, in the event of a system failure, the contents of the queue control table 20 and QUE entry pool 14 may be destroyed or lost. Therefore, conventionally, when a QUE entry is created or deleted with the update of pointer information, the entire queue control table 20 and QUE entry pool 14 are used as a checkpoint, and a checkpoint prepared in an external storage device 23 such as a magnetic disk device is used as a checkpoint. It is written to the point file 24. According to this method, even if a system failure occurs, by using the contents of the checkpoint file 24, the queue control table 20 and the QUE entry pool 14 can be restored to the state before the failure occurred.

[Problems with the background art] However, with the above-mentioned method of writing the entire queue control table and QUE entry pool as a checkpoint, especially in a large-scale system where the QUE entry pool becomes large, it is difficult to write the checkpoint. There was a problem that it took a long time and the response performance deteriorated.

[Purpose of the Invention] This invention was made in view of the above circumstances, and its purpose is to reduce the amount of data written in checkpoint writing performed in preparation for the occurrence of a system failure, thereby shortening the checkpoint writing time. The object of the present invention is to provide an inter-task queue control method that can further improve response performance.

[Summary of the invention] In this invention, QUE prepared in the main storage device
QUE entries (intertask queue entries) held in the (queue) entry pool are
Not only QUE information and next entry pointer, but also a task indicating the task to which the same entry belongs
It also has an ID. In addition, the above QUE
A queue control table is prepared in which a first queue entry pointer and a last queue entry pointer are set for each task in the entry pool. Furthermore, in this invention, a checkpoint file is provided. This checkpoint file stores the corresponding QUE entry when the QUE entry is generated in the QUE entry pool. Also, the QUE in the QUE entry pool
When an entry disappears, the corresponding QUE entry recorded in the checkpoint file is deleted.

According to this invention, when a system failure occurs, each QUE entry recorded in the checkpoint file is read into the QUE entry pool during the recovery process, and the next entry pointer in each QUE entry is set to a common task
By setting and concatenating for each ID, the contents of the QUE entry pool are restored, and the positions of the first and last QUE entries for each task in the restored QUE entry pool are set in the queue control table. Restore table contents.

In addition, in this invention, for a system in which the contents of the QUE entry pool need to be restored in the order in which the QUE entries were created, each QUE entry is provided with generation order information that indicates the generation order of the same entry within the corresponding task. I am trying to set it. In this case, each checkpoint file recorded
When a QUE entry is read into the QUE entry pool after a system failure, the next entry pointer of each QUE entry is set in the generation order indicated by the above generation order information for each common task ID, and the contents of the QUE entry pool are concatenated. is restored in the order in which the QUE entries were created before the system failure. Also,
By setting the positions of the first and last QUE entries for each task in the QUE entry pool restored in this manner in the queue control table, the contents of the table are restored.

[Embodiment of the Invention] An embodiment of the invention will be described below with reference to FIGS. 1 to 3.

In FIG. 1, a computer main body 43 having a CPU 41 and a main storage device 42 and an external storage device 44 such as a magnetic disk device are connected via a channel (not shown), an external bus 45, and the like.
The main storage device 42 has a queue control table 50 that manages inter-task QUE entries for each task, and a QUE entry pool 60 that holds inter-task QUE entries for the entire system.
The queue control table 50 includes information about tasks A and B.
control entry 51 for indicating a QUE entry;
Control entries specific to each task, such as 52, are provided. The control entries 51 and 52 include a first entry pointer indicating the position of the first QUE entry for the corresponding task (A, B), a final entry pointer indicating the position of the final QUE entry for the corresponding task, and a QUE entry for the corresponding task. and a serial number counter indicating the number of generated.

A QUE entry area is reserved in the QUE entry pool 60, and QUE entries are generated in the free area as needed. In Figure 1,
A state in which QUE entries 61 to 63 for task A and QUE entry 64 for task B are generated is shown. QUE entries 61-6
4 is the QUE to be processed next after the entry in question
Next entry pointer indicating the entry position and QUE information passed to the relevant task (inter-task QUE
In addition to the well-known information such as the task ID indicating the destination task of the relevant QUE entry, and the intra-task sequence number (hereinafter simply referred to as sequence number) indicating the generation order (i.e. processing order) of the relevant QUE entry within the relevant task. number).

In this example, the QUE entry for task A is
QUE entry 61, QUE entry 62, and
They are generated in the order of QUE entries 63. Therefore, the serial numbers of QUE entries 61, 62, and 63 are set to 1, 2, and 3, respectively. Also, the next entry pointer of QUE entry 61 is
The next entry pointer of QUE entry 62 points to the position of QUE entry 62.
is set to point to the location. This QUE
Entry 63 is the final QUE entry for task A at that point, so the next entry pointer is set to 0. On the other hand, QUE entry 64 is the first QUE entry to task B, and is also the final QUE entry at that point. Therefore, the next entry pointer of QUE entry 64 is set to 0 and the sequence number is set to 1.

The external storage device 44 has a checkpoint file 46. Each QUE in the QUE entry pool 60 is stored in the checkpoint file 46.
An entry area corresponding to the entry area is secured. Then, in the QUE entry pool 60
Each time a QUE entry is generated, the QUE entry is written to the corresponding entry area in the checkpoint file 46. In addition, the QUE entry written to the checkpoint file 46 is the corresponding one in the QUE entry pool 60.
It is erased (for example, cleared to 0) in response to the disappearance of the QUE entry. Therefore, in this example where QUE entries 61 to 64 are generated in the QUE entry pool 60, the checkpoint file 46 contains QUE entries 61 to 64 as shown in FIG.
64 are written as QUE entries 71-74. Since a QUE entry is written when the entry is generated as described above, the next entry pointers of QUE entries 71 to 74 are all set to 0.

Next, the operation of one embodiment of the present invention will be described as task A.
An example will be explained in which the QUE information in the first QUE entry 61 is extracted and processed, and then a QUE entry for task B is generated. When the processing of the QUE information of QUE entry 61 is completed,
In order to delete the QUE entry 61, the CPU 41 updates the first entry pointer of the control entry 51 for task A prepared in the queue control table 50 and updates the content of the next entry pointer in the QUE entry 61. As a result, the first entry pointer of the control entry 51 points to the position of the QUE entry 62 to be processed next to the QUE entry 61, as shown in FIG.

Next, the CPU 41 transfers the QUE entry to task B to QUE entry 6, which task A was processing.
Create by overlaying 1. That is, CPU41
saves the QUE information for task B (inter-task QUE information) in the QUE entry 61, and then sets the next entry pointer to 0. In addition, the CPU 41 is
The last entry pointer of the control entry 52 for task B prepared in the queue control table 50 is set to the QUE generated by the above overlay.
It is updated to point to the entry position, and the serial number counter is incremented by 1 to 2. In addition, the CPU 41 is
The position of the generated QUE entry is set to the next entry pointer of the QUE entry 64 that the last entry pointer of the control entry 52 was pointing to. This results in the above generated
A QUE entry is the last QUE before the same entry is generated.
entry (and also the first QUE entry)
It is connected to the hot QUE entry 64. Furthermore
The CPU 41 updates the task ID of the generated QUE entry to indicate task B, and sets the serial number to the value (2) of the serial number counter after the counting. In this way, QUE to task A
A QUE entry 65 for task B is generated in the area of entry 61, as shown in FIG. That is, when the QUE entry 61 disappears, the QUE entry 65 is generated.

The CPU 41 sends a QUE entry 65 to task B.
When the QUE entry 65 is generated, the contents of the QUE entry 65 are written to an area in the checkpoint file 46 (on the external storage device 44) that corresponds to the area of the same entry 65 in the QUE entry pool 60. i.e. CPU
41 overlays the contents of the QUE entry 65 on the area of the QUE entry 71 corresponding to the QUE entry 61 as a QUE entry 75 as shown in FIG. That is, deletion of the QUE entry 71 corresponding to the QUE entry 61 and recording of the QUE entry 75 corresponding to the QUE entry 65 are performed simultaneously. Note that when a QUE entry is generated in a different area from the area of the QUE entry to be deleted, it is necessary to erase the contents of the corresponding area of the checkpoint file 46 when the QUE entry is deleted.

Now, assume that a system failure occurs in the state shown in FIG. In this case, the queue control table 50 in the main storage device 42 and the QUE
The contents of the entry pool 60 may be destroyed or lost. Therefore, in the recovery process after a system failure, the queue control table 50
It is also necessary to restore the contents of the QUE entry pool 60 to the state immediately before the system failure occurred. Therefore, the CPU 41 first queries the contents of the checkpoint file 46 in the external storage device 44.
Read into the entry pool 60. As a result, the QUE entry 72 in the checkpoint file 46
~75 are stored in the QUE entry pool 6 as QUE entries 82~85, as shown in FIG.
Written to 0.

Next, the CPU 41 examines all QUE entries in the QUE entry pool 60, sets next entry pointers in ascending order of serial number for each task ID, and connects them. For example, the QUE entry for task A is
There are two QUE entries 82 and 83, and their serial numbers are 2 and 3. Therefore, CPU41
is the next entry pointer of QUE entry 82,
The position of the QUE entry 83 is set, and the next entry pointer of the QUE entry 83 is set to 0. As a result, the QUE entries 82 and 83 are restored as the QUE entries 62 and 63 in FIG. 2.

Next, the CPU 41 reads the queue control table 5.
The QUE restored to the QUE entry pool 60 is set to the first entry pointer of the control entry 51 in 0.
Entry 62 (first QUE entry to task A)
and also the final entry pointer
Set the position of the QUE entry 63 (first QUE entry for task A). And CPU41 is
The serial number (3) of the QUE entry 63, which is the final QUE entry, is set in the serial number counter of the control entry 51. As a result, the contents of the control entry 51 are restored. By performing the above processing for all valid tasks in the QUE entry pool 60, the contents of the queue control table 50 and the QUE entry pool 60 are restored.

In the above embodiment, a case has been described in which a serial number counter is provided in the control entry, but the present invention is not limited to this. For example, when generating a QUE entry, the final QUE at that time
By setting the value obtained by adding 1 to the serial number of the entry (intra-task serial number) as the serial number of the generated QUE entry, it is possible to eliminate the need for a serial number counter in the control entry. Furthermore, in the above embodiment, a case has been described in which a sequence number (intra-task sequence number) is applied as information indicating the generation order of QUE entries (for each task), but time information such as a system clock may also be used. It is possible. In short, when restoring the queue control table and QUE entry pool, (for each task)
Any information that can connect QUE entries in the order of generation is sufficient.

Furthermore, in the above embodiment, a case was explained in which the generation order of QUE entries is also completely restored, but in a system where it is not necessary to restore the QUE entries in the same order as they were created, it is sufficient to identify the destination task, and it is sufficient to use the serial number (not to mention the serial number counter). is not necessary.

[Effect of the invention] As detailed above, according to this invention, QUE
When an entry is created or deleted, only the corresponding QUE entry is recorded or deleted in the checkpoint file, and system failures can be dealt with. Therefore, compared to the conventional method in which the entire queue control table and QUE entry pool are subject to checkpoint writing, checkpoint writing time can be shortened and response performance can be further improved.

[Brief explanation of drawings]

FIG. 1 is a correlation diagram of the queue control table, QUE entry pool, and checkpoint file before QUE entry generation in an embodiment of the present invention, and FIG. 2 is a diagram showing the state after QUE entry generation in FIG. 1. , FIG. 3 is a diagram showing the state in which the contents of the checkpoint file are read into the QUE entry after the system failure occurs in FIG.
Figure 4 is a diagram explaining the relationship between tasks and inter-task queues (QUE), and Figure 5 is a diagram explaining the relationship between tasks and inter-task queues (QUE).
Queue control table before QUE entry generation and
FIG. 3 is a correlation diagram between a QUE entry pool and a checkpoint file. 41...CPU, 42...Main storage device, 46...Checkpoint file, 50...Queue control table, 51...Control entry, 60...QUE entry pool, 61-65, 71-75,
82 to 85...QUE entries (intertask queue entries).

Claims (1)

[Scope of Claims] 1. In a system in which each task performs processing by passing inter-task queue information, an inter-task queue entry having the above-mentioned inter-task queue information has a task ID indicating the task to which the entry belongs;
and a queue entry pool formed on a main storage device that holds an intertask queue entry further having a next entry pointer indicating the position of the intertask queue entry to be processed next to the same entry; The queue control table, which has a first queue entry pointer and a last queue entry pointer for each task in the entry pool, is formed on the main storage device, and when the inter-task queue entry is created or deleted, and a checkpoint file in which inter-task queue entries are recorded and deleted, and the inter-task queue entries recorded in the check-point file are read into the queue entry pool after a system failure, and the inter-task queue entries are read into the queue entry pool after a system failure. By setting and concatenating the next entry pointer of user entries for each common task ID, the contents of the queue entry pool are restored, and the first and last keys of each task in the restored queue entry pool are An inter-task queue control method characterized in that the contents of the queue control table are restored by setting the position of the user entry in the queue control table. 2. In a system in which each task performs processing by passing inter-task queue information, an inter-task queue entry having the above-mentioned inter-task queue information, a task ID indicating the task to which the entry belongs;
A main unit that holds intertask queue entries that further includes generation order information indicating the generation order of the same entry within the corresponding task, and a next entry pointer indicating the position of the intertask queue entry to be processed next to the same entry. A queue control table formed on the main storage device, having a queue entry pool formed on the storage device, and a first queue entry pointer and a final queue entry pointer for each task in the queue entry pool. and a checkpoint file in which the corresponding intertask queue entry is recorded and deleted when the intertask queue entry is created or deleted, and each of the intertask queue entries recorded in the checkpoint file, After a system failure, the above queue entries are read into the above queue entry pool, and the next entry pointers of the above inter-task queue entries are set and concatenated in the generation order indicated by the above generation order information for each common task ID. In addition to restoring the contents of the pool, the contents of the table are restored by setting the positions of the first and last queue entries for each task in the restored queue entry pool in the queue control table. An inter-task queue control method.