JPH10293712A - File access processing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the delay of updating during rollback and to improve throughput in exclusive control at the time of deadlock generation and at the time of program abnormal end by originating a request for unlocking before starting the rollback to an exclusive control means. SOLUTION: In the case that an updating cancellation request is originated from a program 11, an updating cancellation means 18 operates the exclusive control means 13, originates an unlocking request before starting the rollback and rolls back the contents of a gathering file 35 to a data file 34 based on a gathering information table 23. Then, after the completion of the rollback, the exclusive control means 13 is operated and the unlocking request is newly originated. That is, in this system, by originating the request for unlocking before starting the rollback to the exclusive control means 13, even a rollback object block is accessed from the other program.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a file access processing system in a computer, and more particularly, to a file access processing system that performs effective exclusive control on a process in which many programs refer to and update the same data file without inconsistency.

[0002]

2. Description of the Related Art Hereinafter, a conventional exclusive control method will be specifically described.

Conventionally, exclusive control of a file is performed by dividing a data file into certain blocks so as to avoid inconsistency in file contents when a plurality of programs update and refer to one data file at the same time. Exclusive control was performed on a per-unit basis.

That is, the updated block is in an update locked state, and the updated locked block cannot be updated or referred to by other programs unless the program is conscious of issuing an update completion instruction, and is in a wait state. Also, the referenced block is in a reference lock state, and the reference locked block can be referred to from other programs but cannot be updated unless an update completion instruction is similarly issued.

Here, the update completion instruction is an instruction to be issued to the OS when the program completes a series of reference and update and the file contents are logically correct. All the blocks locked by this are unlocked. Thus, the locked block can be referenced and updated from another program. Hereinafter, this update completion instruction is referred to as a checkpoint.

As described above, the access to the data file may be delayed due to the exclusive control of the file, which has been a cause of a decrease in throughput. Various proposals have been made to reduce this delay.

[0007] For example, in Japanese Patent Application Laid-Open No. 3-123946, "Exclusive control method of database", a program (= transaction) for accessing a data file is
Update programs that perform reference and update and search programs that perform only reference are categorized. Update programs are managed by multi-version simultaneous execution control using two-phase locks, and search programs are executed by multi-version simultaneous execution using the basic time stamp order. It is configured to be managed by control.

The multi-version simultaneous execution control using the two-phase lock means that when a certain block is updated, it has two contents before and after the update, and if the block being updated is referred to, In this case, the image before the update is referred to, and when the update lock is unlocked, the reference lock is changed to a lock called a guaranteed lock that cannot be referenced or updated.

The multi-version simultaneous execution control using the basic time stamp order means that when a certain block is referred to, time information called a read stamp is stored as block information, and when updated, time information called a write stamp is stored in the block. The information is stored as information, and the program itself also has a time stamp, which is the time information at which the program is started, and exclusive control is performed without contradiction by using the time stamp.

That is, the contents of a new block are accumulated every time a block is updated, and for a reference or update to a certain block, the block having the largest write stamp before the time stamp of the accessing program is selected. In this method, the update is permitted when the read stamp of the block is earlier than the time stamp of the program, and the block is referred to at the time of update according to the rule that update lock cannot be performed on the block at the same time. The purpose was to reduce the delay as much as possible.

In order to eliminate incomplete updating of the data file when the program is abnormal, the contents before updating the target block (hereinafter referred to as an image before updating) are stored in a collection file prepared for each program and each data file when updating the data file. (Hereinafter referred to as "collection"), and automatically write back to a data file when a program error or system error occurs.

When the rollback function operates simultaneously with the exclusive control of the file, since the rollback is also a kind of data file update, the block which has been locked for update is not unlocked until the rollback processing is completed. Was.

When a check point is taken, the locked image is unlocked and the pre-update image in the collected file is discarded.
This rollback function is also used when a deadlock occurs in the exclusive control (a program takes a block and falls into a permanent delay).

[0014]

The above-described conventional exclusive control system has various problems as described below.

A first problem is that during a rollback of a program, the block being rolled back cannot be updated, and if the rollback takes a long time, the throughput may decrease. The reason is that the conventional technology does not consider the rollback and treats it in the same manner as a normal update.

The second problem is that when a large number of update programs are accessing the same file, the possibility that the update programs are stopped is increased, and the total processing time is rather increased. The reason is that multi-version simultaneous execution control using two-phase lock is performed between update programs, and if the update program refers to a block on which update lock is performed, it is guaranteed locked at the time of update completion processing, and the referenced block is updated If you try to do so, you will have to abort the program because it refers to an old version of the block.

A third problem is that when many programs access the same block, images of many blocks are created and the size of the database may increase. The reason is that as long as there is a program that refers to the old version, even if the update lock is released, the referring image remains.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, eliminate delays in file updating during rollback, and improve throughput in exclusive control when a deadlock occurs or when a program terminates abnormally. An access processing system is provided.

Another object of the present invention is to provide a file access processing system capable of avoiding a situation in which the update program has to be stopped and avoiding an increase in processing time.

Still another object of the present invention is to provide a file access processing system capable of preventing an increase in the size of a data file due to a collected file used for rollback.

[0021]

A file access processing system according to the present invention, which achieves the above object, comprises a plurality of programs that simultaneously execute the same data file by exclusive control in units of blocks obtained by dividing and numbering the data file. When a lock request or an unlock request for reference or update is made to the block, an exclusive control unit that manages the block to be accessed by the block number, locks and unlocks the block, An exclusive control table for registering lock information indicating the type of reference or update lock of the block locked by the exclusive control means, and before updating the target block,
Pre-update image collecting means for collecting the pre-update image of the block, a collection file storing the collected pre-update image, and collection information storing information of the block corresponding to the pre-update image collected by the update A table and, at the time of updating the target block, referring to the collection information table, and a pre-update image checking means for checking whether to collect a pre-update image of the target block;
File read / write means for reading or writing the target block with respect to the data file, checkpoint means for unlocking the locked target block by the update completion instruction and discarding the pre-update image, and update lock by the update cancel request Update canceling means for requesting the exclusive control means to unlock the obtained block, and performing update canceling processing for returning blocks of the collected file to the data file based on the collected information table.

According to a second aspect of the present invention, in the file access processing system according to the second aspect of the present invention, the exclusive control unit is configured to execute a lock request for a reference or an update when the lock information of the block for which the lock request has been made is another information. If the lock request and the lock information are registered in the exclusive control table for a program, the lock information of the block for which the lock is requested is added to the exclusive control table, and the reference must be made. For example, it is checked whether the lock-requested block is in the process of canceling the update. If the block is not in the process of canceling the update, the process waits for the unlocking of the block. Acquiring the position information of the block on the collection file, and if the lock request is an update, the collection information table The delete the information of the block by adding lock information of the lock requested block in the exclusive control table, if the lock request is referenced,
The lock information of the block requested to be locked is added to the exclusive control table.

According to a third aspect of the present invention, in the file access processing system, the exclusive control table includes, for each of the plurality of programs, lock information of reference or update lock of the block and information indicating whether update cancellation processing is being performed. The exclusive control means determines whether or not the block requested to be locked is undergoing an update canceling process based on information indicating whether or not the update canceling process is being performed on the table for each program. It is characterized by doing.

According to a fourth aspect of the present invention, in the file access processing system, the exclusive control table includes, for each of the plurality of programs, lock information of block reference or update lock, and information indicating whether update cancellation processing is being performed. A plurality of tables for registering the same. When the unlock request is made, the exclusive control unit checks whether the lock is unlocked before the update cancellation processing. Information indicating that the update is being canceled is added to the table of the program that issued the table unlock request, and the reference lock information of the table is deleted only for the block that has been locked for reference. For example, the lock information of all the blocks on the table of the program that has issued the unlock request of the exclusive control table and And deletes the information indicating that the new cancel processing.

According to a fifth aspect of the present invention, in the file access processing system according to the fifth aspect of the present invention, the exclusive control unit is configured to execute a lock request for a reference or an update when the lock information of the block for which the lock request has been made is another information. If the lock request and the lock information are registered in the exclusive control table for a program, the lock information of the block for which the lock is requested is added to the exclusive control table, and the reference must be made. For example, it is checked whether the lock-requested block is in the process of canceling the update. If the block is not in the process of canceling the update, the process waits for the unlocking of the block. Acquiring the position information of the block on the collection file, and if the lock request is an update, the collection information table The delete the information of the block by adding lock information of the lock requested block in the exclusive control table, if the lock request is referenced,
The lock information of the block whose lock has been requested is added to the exclusive control table, and the pre-update image check unit, if the information of the block is not stored in the collection information table, stores the information of the block in the collection information table. Adding information, the before-update image collecting means,
The pre-update image of the block added to the collection information table is read from the collection file for the other program, and written to the collection file for the program that issued the lock request. If so, the block is written to the data file, and if it is referenced, the block is read from the collection file or the data file for the program that issued the lock request.

[0026]

Next, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG.
The embodiment of the present invention relates to a data processing device 10 operated by program control, a main storage device 20 composed of a semiconductor, and an auxiliary storage device 3 composed of a disk device or the like.
0.

The data processing device 10 includes a program 11
, File access means 12 and exclusive control means 13
, A pre-update image checking unit 14, a pre-update image collection unit 15, a file I / O unit 16, a checkpoint unit 17, and an update canceling unit 18.

The main storage device 20 has an exclusive control table 22
And a collection information table 23. Further, the auxiliary storage device 30 includes a data file 34 divided and managed in blocks of a fixed size, and a collection file 35.

The exclusive control table 22 is a table for storing information on locked blocks, and includes, for each locked program, a block number, a lock type (indicating whether reference lock or update lock), and a role. Information such as a display indicating that a back is being performed is stored.

The collection information table 23 stores the program 11
Is a table for storing the information of the pre-update image collected by the pre-update image collecting means 15 by the update of the pre-update, and stores information such as the position of the collected file, the collected block number, and the block number of the corresponding collected file. doing.

The collection file 35 is a file for storing the pre-update image collected by the pre-update image collection means 15 by updating the program 11.

When the program 11 accesses the data file 34 for reference and update, the file access unit 12 first operates the exclusive control unit 13.

The exclusive control means 13 checks the number of the block to be accessed based on the exclusive control table 22, and determines whether or not the block can be locked.
If the lock is impossible, the process waits until the target block is unlocked. If the lock is possible, information such as the block number and lock type of the target block is registered in the exclusive control table 22 and locked.

The file access means 12 operates the file I / O means 16 at the time of reading, and operates the pre-update image checking means 14 at the time of writing, according to the type of access (read or write).

The pre-update image checking means 14 determines whether the pre-update image of the target block has already been collected from the collection information table 23 corresponding to the request source program.

The file access means 12 operates the file I / O means 16 when referring to or when the pre-update image of the target block has already been collected, and collects the pre-update image when it has not been collected yet. The means 15 is operated.

The pre-update image collection means 15 reads the contents of the target block from the data file 34,
The contents are written to the collection file 35 corresponding to the program 11.

The file I / O means 16 reads the contents of the target block from the data file 34 or writes data to the target block of the data file 34 according to the request.

When the program 11 takes a checkpoint, the file access means 12 operates the checkpoint means 17.

The checkpoint unit 17 issues an unlock request to the exclusive control unit 13, discards all pre-update images in the collection file 35, and deletes the collection information table 2.
3 is initialized.

When an update cancellation request is issued from the program 11, the update cancellation means 18 operates the exclusive control means 13, issues an unlock request before the start of rollback, and based on the collection information table 23, 35
Is rolled back to the data file 34, and after the rollback is completed, the exclusive control unit 13 is operated, and an unlock request is issued again.

A feature of the embodiment of the present invention is that the block locked by the update canceling means 18 is not unlocked until the end of rollback in the prior art, but is unlocked before the start of rollback. By issuing a request to the exclusive control means 13, the rollback target block can be accessed from another program.

Hereinafter, the operation of the embodiment of the present invention configured as described above will be described in detail with reference to FIG. 1 and FIGS.

A request for the program 11 to access the data file 34 or to take a checkpoint is received by the file access means 12. In FIG. 2 showing the processing of the file access means 12, the file access means 12 determines this request (step 20).
1) If the request is a file access request such as reference or update, the exclusive control means 13 is operated (step 202), a lock request for the access target block is issued, and if the checkpoint request is made, the checkpoint means 17 is operated (step 208). .

In FIG. 3 showing the processing of the exclusive control means 13, the activated exclusive control means 13 determines whether the request is locked or unlocked (step 301). It is checked whether the target block exists in the table (step 30).
2). If the target block does not exist in the table for the other program of the exclusive control table 22, that is, if the target block is not locked by another program, it becomes accessible, and the exclusive control table 22 is set as a target lock as an update lock or a reference lock depending on the access type. Add a block (steps 303, 304, 30)
5).

If the target block exists in another program table other than the exclusive control table 22, access is permitted because reference-based access is possible (step 306). In the case of updating and reference and updating, it is checked whether or not there is a display indicating that rollback is being performed in the program that is updating and locking the target block (step 307). Since the access is not possible, it waits for the unlock of the block of the other program (step 308).

If there is a display indicating that rollback is in progress for all programs that have updated and locked the target block, simultaneous access is possible, and the position of the target block on the collection file 35 is obtained from the collection information table 23 (step 30).
9). If the access type is checked and referred to, it is added as a reference lock to the exclusive control table 22 (steps 310 and 304). If the access type is updated, the block is not rolled back. The information of the target block on the collection information table 23 of the program is deleted (step 311) and added as an update lock to the exclusive control table 22 (step 30).
5).

If the request is an unlock request in step 301, it is checked whether the lock is unlocked before the start of rollback (step 312). If the lock is unlocked before the start of rollback, the target program on the exclusive control table 22 is rolled. Only the blocks that have been back-locked by adding the display being backed are deleted from the exclusive control table 22 and unlocked (step 314); otherwise, information and rolls of all blocks of the target program on the exclusive control table Delete the display being backed up (step 31)
3) Unlock the locked block. When the processing is completed, the process returns to the file access unit 12.

In FIG. 2, the file access means 12
Returns from the exclusion control means 13 and operates the file I / O means 16 for reference according to the type of access (steps 203 and 207), and operates the pre-update image check means 14 for update (step 204).

In FIG. 4 showing the processing of the pre-update image checking means 14, the pre-update image checking means 14 is used.
Checks whether there is information on the block to be updated in the collection information table 23 (step 401). If there is no information on the block to be updated, it is necessary to collect a pre-update image. The information is added (step 402), and if there is information on the target block, the process returns to the file access means 12 without doing anything.

In FIG. 2, the file access means 12
Returns from the pre-update image checking means 14 to operate the file I / O means 16 if the pre-update image has been collected (steps 205 and 207), and to collect the pre-update image if it is necessary to collect the pre-update image. Means 15
Is operated (step 206).

In FIG. 5 showing the processing of the pre-update image collection means 15, the pre-update image collection means 15 checks whether the target block exists in the collection file 35 for another program (step 501). , The pre-update image of the target block is read from the collection file (step 502),
If it does not exist in the collection file 35, the target block is read from the data file 35 (step 504). The read pre-update image is written to the collection file 35 (step 503), and the file access unit 1
Return to 2.

In FIG. 2, the file access means 12
Operates the file I / O unit 16 after returning from the pre-update image collection unit 15.

FIG. 6 showing the processing of the file I / O means 16
, The file I / O means 16 first checks whether or not the target block is a reference (step 601). (Steps 602 and 603) If it is in the data file 34, it is read from the data file 34 (Step 6).
02, step 604). If the data file 34 is to be updated, it is written to the target block of the data file 34 (step 60).
5).

In FIG. 2, the file access means 12
Receives the checkpoint request from the program 11, operates the checkpoint unit 17 (step 208).

In FIG. 7 showing the processing of the check point means 17, the check point means 17 first operates the exclusive control means 13 (step 701) to unlock all locked blocks. Next, the collection information table 23 is initialized (step 702), and all pre-update images are discarded.

Next, the operation of the update canceling means 18 will be described with reference to FIG. When the program 11 issues an update cancellation request for the data file 14 automatically or when the program 11 is conscious, for example, when the program 11 ends abnormally, the update cancellation means 18 operates.

The update canceling means 18 firstly receives the exclusive control means 1
3 (step 801), issues an unlock request before the start of rollback, and makes the block locked by reference and update accessible from other programs.
Perform a rollback. That is, the collection information table 23
Are sequentially written back from the collection file 35 to the data file 34 one by one (step 802). Then, when the rollback is completed, the exclusive control means 13 is operated (step 803), an unlock request is issued, and the locked block is actually deleted from the exclusive control table 22.

As described above, according to the embodiment of the present invention, before the rollback starts, the locked block is unlocked, and the rollback target block is made to access the collected file. Simultaneous update to the rollback target block becomes possible.

Conventionally, during rollback, the block to be rolled back cannot be accessed until the rollback is completed, such as access to the update or the like. Therefore, even in the method disclosed in Japanese Patent Application Laid-Open No. 3-123946, the reference program can only be referred to and cannot be accessed. Thus, when the update program is referred to and attempts to update, the update program is stopped. In the method according to the present embodiment, such a delay is eliminated, and the throughput of exclusive control during rollback is improved. Things.

In the method according to the present embodiment, when accessing the block to be rolled back, not only the update but also the collection file to be rolled back cannot be referred to, and the contents at the time of access to the block cannot be updated. Is the same as the content after the rollback is completed, the logical validity of the file content is maintained, and no inconsistency of the file content occurs. Further, by using the rollback function, it is not necessary to take up a new file space, and the capacity of the auxiliary storage device is not reduced.

[0062]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings.

In this embodiment, the program 1 shown in FIG.
1 include programs 11a, 11b, and 11z shown in FIG.
9 accesses the same data file 34 (consisting of block numbers 21 to 35) having the contents shown in FIG.
Indicates the contents of the exclusive control table 22 at that time.

Here, the program 11a has already accessed the block numbers 23, 25 and 26 of the data file 34, and the program 11b has the block number 2
7 and 29 have already been accessed. It is also assumed that the program 11z is in a state where, after accessing the block numbers 30, 31, and 32, the program ends abnormally and rollback is started. Similarly, FIG. 10 shows the contents of the collection information table 23, and FIG. 11 shows the contents of the collection file 35, respectively.

In the states shown in FIGS. 1 and 9 to 12, the program 11z operates the update canceling means 18, and the update canceling means 18 operates the exclusive control means 13 (step 8).
01), issue an unlock request before the start of rollback,
Immediately after it is completed. That is, the exclusive control means 13 is an unlock request (step 301), and is unlocked before the rollback is started (step 31).
2) Only the blocks that have been roll-backed in the table for the program 11z in the exclusive control table 22 with the reference locked are deleted from the exclusive control table 22 and unlocked (step 314), and the update canceling means 18 It is the state returned to.

Similarly, in the state shown in FIG.
When the file access unit 12 tries to refer to the block number 31 of the data file 34, the file access unit 12
3 is operated (steps 201 and 202). Since the exclusive control means 13 is a lock request (step 301),
It is checked whether the exclusive control table 22 has the block number 31 (step 302). At this time, the block number 3 is stored in the table for the program 11z in the exclusive control table 22.
Since the number 1 exists, when the display during rollback is checked (steps 306 and 307), there is a display during rollback, and access is possible.

Then, the position on the collection file to be actually accessed is acquired from the collection information table 23z (step 309), and finally, the block number 31 is added as a reference to the program 11a table of the exclusive control table 22 ( Step 304), file access means 12
Return to

The file access means 12 operates the file I / O means 16 because the access type is referred to (step 203) (step 207). File I /
The O means 16 refers to the access (step 60).
1) Since the block number 31 exists in the collection file 35z (step 602), the block number 42z corresponding to the block number 31 of the data file 34 is read from the collection file 35z (step 303), and the process returns to the program 11a.

Similarly, in the state shown in FIG.
When the user attempts to refer to the block number 22 of the data file 34, the file access means 12 first operates the exclusive control means 13 (steps 201 and 202). The exclusive control unit 13 determines that the request is a lock request (step 30).
1) It is checked whether or not the exclusive control table 22 has the block number 22 (step 302). Since the block number 22 does not exist, the program 11 of the exclusive control table 22
The block number 22 is added to the table for b as a reference (steps 303 and 304), and the file access means 1 is added.
Return to 2.

The file access means 12 operates the file I / O means 16 (step 207) because the access is a reference (step 203). File I /
The O means 16 refers to the access type (step 60).
1) Since the target block exists in the data file 34 (step 602), the content of the block number 22 is read from the data file 34 (step 60).
4) Return to the program 11b.

Similarly, in the state shown in FIG.
When the user attempts to update the block number 32, the file access unit 12 operates the exclusive control unit 13 (steps 201 and 202). Since the exclusive control means 13 is a lock request (step 301), the exclusive control table 22
Check if there is a block number 32 (step 3
02). Since the block number 32 is in the table for the program 11z and further has a display indicating that rollback is being performed (steps 306 and 307), it is determined that the access is possible.

The position of the block number 32 on the collection file 35 (the block number 43z of the collection file 35z) is obtained from the collection information table 23z (Step 309).
The information of the block number 32 is deleted from the collection information table 23z so that the block is not rolled back (steps 310 and 311).
The block number 32 is added to the table for the program 11a as an update (step 305), and the process returns to the file access means 12.

The file access unit 12 operates the pre-update image check unit 14 because the update is an update (steps 203 and 204). The pre-update image checking means 14 checks all the information in the collection information table 23a, but since the block number 32 is not registered (step 401), adds the block number 32 to the collection information table 23a (step 402). The process returns to the file access means 12.

Since the block number 32 has not been collected, the file access means 12 operates the pre-update image collecting means 15 (steps 205 and 206). The pre-update image collection unit 15 reads the block number 32 from the block number 43z of the collection file 35z, writes the content into the block number 43a of the collection file 35a (steps 501, 502, 503), and returns to the file access unit 12. The file access means 12
The file I / O means 16 is operated (step 20).
7) Update the data file 34.

The file I / O means 16 writes the contents specified by the program 11a to the block number 32 of the data file 34 (step 60).
1, 605), and returns to the program 4a.

In the state shown, when the program 11b issues a write request to the block number 21, the file access means 12 operates the exclusive control means 13 (steps 201 and 202). Since the exclusive control unit 13 is the lock request (step 301), the exclusive control table 22
Is checked (step 302), but since the block number 21 does not exist, it is determined that access is possible. Since this is an update (step 303), the block number 21 is added as an update to the table for the program 11b of the exclusive control table 22 (step 305), and the file access unit 1
Return to 2.

Next, the file access means 12 operates the pre-update image checking means 14 (step 20).
3, 204). The pre-update image check unit 14 checks all information in the collection information table 23b, and adds the block number 21 to the collection information table 23b (Step 402) because the block number 21 is not registered (Step 401). Return to the access means 12.

Since the block number 21 has not been collected, the file access unit 12 operates the pre-update image collection unit 15 (steps 205 and 206). The pre-update image collection unit 15 reads the block number 21 from the data file 34 and
5b is written to the block number 43b (step 50).
1, 504, 503), and returns to the file access means 12.

The file access means 12 stores the file I
The / O means 16 is operated (step 207), and the data file 34 is updated. Since the file I / O means 16 is an update (step 601), the contents specified by the program 11b are stored in the block number 21 of the data file 34.
(Step 605), and returns to the program 11b.

In the state shown, when the program 11a attempts to update the block number 25, the file access means 12 operates the exclusive control means 13 (steps 201 and 202). The exclusive control unit 13 checks the exclusive control table 22 because the lock request is a lock request (step 301), and determines that the block number 26 is accessible because only the program 11a locks the block number 25 (step 302). . Then, because the update is an update (step 303), the block number 25 is added as an update lock to the table for the program 11a in the exclusive control table 22, but since the table already exists, nothing is done (step 305) and the file access is performed. Means 12
Return to

Next, the file access means 12 operates the pre-update image checking means 14 (step 20).
3, 204). The pre-update image check unit 14 checks all the information in the collection information table 23a, and returns to the file access unit 12 without doing anything because the block number 25 is registered (step 401).

Since the file access means 12 has already collected the block number 25 (step 205),
Operate the file I / O means 16 (step 20)
7). Since the file I / O means 16 is an update (step 601), the contents specified by the program 11a are written to the block number 25 of the data file 34 (step 606), and the program returns to the program 11a.

In the state shown, when the program 11b attempts to update the block number 25, the file access means 12 operates the exclusive control means 13 (steps 201 and 202). The exclusive control unit 13 checks the exclusive control table 22 because the request is a lock request (step 301). When the exclusive control unit 13 checks the exclusive control table 22, the block number 25 is present in the table for the program 11a (step 302). Since there is no display indicating that the rollback is in progress (step 307), the program 11a waits until the program 11a unlocks the block number 25 (step 3).
08).

Similarly, in the state shown in FIG.
Takes a checkpoint, the file access means 12 determines that the request is a checkpoint request (step 2).
01), the checkpoint unit 17 is operated (step 208). The checkpoint unit 17 first operates the exclusive control unit 13 (step 701) and issues an unlock request. The exclusive control unit 13 determines that the unlock request is made before the rollback is started (step 31).
2), the block numbers 23, 25, 26 locked to the table of the program 11a of the exclusive control table 22
(Step 313), all the locked blocks are unlocked, and the process returns to the checkpoint unit 17. Checkpoint means 17
Deletes the information of the block numbers 26, 26 registered in the collection information table 23a next (step 70).
2) By doing so, the information in the collection information table 23a is initialized, and if the program 11a terminates abnormally, the contents of the blocks in the collection file of the data file 34 are not written back by rollback, and the program 11a Return to

After the state shown in the figure, the update canceling means 18 operated by the program 11z stores the blocks (block numbers 30, 31, 3) registered in the collection information table 23z.
2) is sequentially written back from the collection file 35z to the data file 34 one by one (step 801). After writing back the data of all the blocks existing in the collection information table, the exclusive control means 13 is operated (step 803).
Issue an unlock request.

The exclusive control means 13 deletes the table for the program 11z of the exclusive control table 22 and displays the message indicating that the rollback is being performed because the request is for unlocking (step 301) and the rollback is not started (step 312). Erase (step 313), the program 11z ends.

Although the present invention has been described with reference to the preferred embodiments and examples, the present invention is not necessarily limited to the contents of the above embodiments and examples.

[0088]

According to the exclusive control system of the present invention as described above, the following effects can be obtained.

First, it is possible for a program to update a block being rolled back and to simultaneously access the same block by another program, thereby improving throughput. The reason is that all the blocks to be rolled back are unlocked before the rollback starts, and the access to the blocks from other programs is performed to the collected file.

Second, it is possible to avoid an increase in the processing time due to the suspension of the update program, without falling into a state in which the update program must be discontinued as in the related art. The reason is that the multi-version simultaneous execution control using the two-phase lock is not used, and the contents of the old block are not referred to.

Third, there is no increase in the size of the data file as in the prior art. The reason is that since the reference is performed using the collected file used for rollback, it is not necessary to secure a new file space every time the update is performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a file access processing system according to an embodiment of the present invention.

FIG. 2 is a flowchart showing processing of a file access unit of the file access processing system according to the embodiment of the present invention.

FIG. 3 is a flowchart showing processing of an exclusive control unit of the file access processing system according to the embodiment of the present invention.

FIG. 4 is a flowchart showing a process of a pre-update image check unit of the file access processing system according to the embodiment of the present invention.

FIG. 5 is a flowchart showing a process of a pre-update image collection unit of the file access processing system according to the embodiment of the present invention.

FIG. 6 is a flowchart showing processing of a file I / O means of the file access processing system according to the embodiment of the present invention.

FIG. 7 is a flowchart showing a process of a check point unit of the file access processing system according to the embodiment of the present invention.

FIG. 8 is a flowchart showing a process of an update canceling unit of the file access processing system according to the embodiment of the present invention.

FIG. 9 is a diagram illustrating contents of an exclusive control table of the file access processing system according to the embodiment of the present invention;

FIG. 10 is a diagram exemplifying the contents of a collection information table of the file access processing system according to the embodiment of the present invention.

FIG. 11 is a diagram illustrating contents of a collection file of the file access processing system according to the embodiment of the present invention;

FIG. 12 is a diagram illustrating contents of a data file of the file access processing system according to the embodiment of the present invention;

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 data processing device 20 main storage device 30 auxiliary storage device 11 program 11 a-11 z program 12 file access means 13 exclusive control means 14 pre-update image check means 15 pre-update image collection means 16 file 1/0 means 17 checkpoint means 18 update Canceling means 22 Exclusive control table 23 Collection information table 23a to 23z Collection information table for each program 34 Data file 35 Collection file 35a to 35z Collection file for each program

Claims (5)

[Claims] 1. A lock request or an unlock request for referring to or updating a block of the same data file from a plurality of programs is simultaneously performed by exclusive control in units of blocks obtained by dividing and numbering a data file. In this case, an exclusive control unit that manages a block to be accessed by the block number and locks and unlocks the block, and indicates a type of reference or update lock of the block locked by the exclusive control unit An exclusive control table for registering lock information; a pre-update image collecting means for collecting a pre-update image of the block before a target block is updated; a collection file for storing the collected pre-update image; The information of the block corresponding to the updated pre-update image is stored. A collection information table, a pre-update image check unit that refers to the collection information table at the time of updating the target block, and checks whether to collect an image before update of the target block; and reads or writes the target block to the data file. File read / write means to be executed, checkpoint means for unlocking a target block locked by an update completion instruction and discarding a pre-update image, and exclusive control means for unlocking an update-locked block by an update cancellation request And an update canceling unit for performing an update canceling process for returning the blocks of the collection file to the data file based on the collection information table. 2. The exclusive control unit according to claim 1, wherein a lock request for reference or update is issued, and the lock information of the block for which the lock is requested is registered in the exclusive control table for another program. If the lock request and the lock information refer to each other, the lock information of the lock-requested block is added to the exclusive control table. If not, the update of the lock-requested block is canceled. Check whether the process is in progress, wait for the unlocking of the block if not in the update canceling process, and if the update canceling process is in progress, obtain the position information of the block on the collection file from the collection information table If the lock request is an update, the information of the block in the collection information table is deleted and the lock request is issued. The lock information of a block to which the lock is requested is added to the exclusive control table, and if the lock request is a reference, the lock information of the block for which the lock is requested is added to the exclusive control table. File access processing system. 3. The exclusive control table includes a plurality of tables for registering, for each of the plurality of programs, lock information of reference or update lock of the block and information indicating whether or not update cancellation processing is being performed. 3. The control unit according to claim 2, wherein the control unit determines whether or not the block requested to be locked is in the process of canceling the update, based on information indicating whether or not the update of the table of each program is in the process of canceling the update. File access processing system. 4. The exclusive control table includes a plurality of tables for registering, for each of the plurality of programs, lock information of reference or update lock of the block and information indicating whether or not update cancellation processing is being performed. The control means, when an unlock request is made,
Check whether it is unlocked before the update cancellation processing, if it is unlocked before the update cancellation processing, add information indicating that the update cancellation processing is being performed to the table of the program that issued the unlock request of the exclusive control table, The reference lock information of the table is deleted only for the block that has been reference locked. If the lock is not unlocked before the update cancellation processing, the lock information of all blocks on the table of the program that issued the unlock request of the exclusive control table 2. The file access processing system according to claim 1, wherein the information indicating that the update is being canceled is deleted. 5. The exclusive control unit, wherein a lock request for reference or update is made, and the lock information of the block for which the lock is requested is registered in the exclusive control table for another program. If the lock request and the lock information refer to each other, the lock information of the lock-requested block is added to the exclusive control table. If not, the update of the lock-requested block is canceled. Check whether the process is in progress, wait for the unlocking of the block if not in the update canceling process, and if the update canceling process is in progress, obtain the position information of the block on the collection file from the collection information table If the lock request is an update, the information of the block in the collection information table is deleted and the lock request is issued. Adding the lock information of the block to the exclusive control table; if the lock request is a reference, adding the lock information of the lock-requested block to the exclusive control table; If the information of the block is not stored in the information table, the information of the block is added to the collection information table, and the pre-update image collection unit calculates the pre-update image of the block added to the collection information table. Reading from the collection file for the other program, writing to the collection file for the program that issued the lock request, the file I / O means, if the update, writes the block to the data file; If referenced, the collection file for the program that issued the lock request Other file access processing system according to claim 1, characterized in that reading the blocks from the data file.