JPH0589050A - File recovery control system - Google Patents

Abstract

PURPOSE:To speed up and facilitate the recovery control of a file used for processing a transaction, and to define the capacity of the use file. CONSTITUTION:First and second images are possessed in the respective records of a file area 22. The respective bits of a bit map 12 are made correspondent to the respective records and at the bits '0' and '1', it is displayed whether the latest data are shown in the first image or the second image. Transaction access information 11 registers the identifier of the record updated in the transaction processing for each file. When an updating request in received, a record update part 4 updates the image into the other image not shoeing the latest data while referring to a bit 12, and the identifier of the record is registered on the transaction access information 11. When an approval input is received, a transaction approval processing part 5 inverts the value of the bit map.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a file recovery control system,
In particular, the present invention relates to a file recovery control method for controlling the contents of a file to a state after completion of transaction processing or a state before processing is started, by approval or denial of update of a file used for transaction processing of an electronic computer system.

[0002]

2. Description of the Related Art Conventionally, this type of file recovery control system stores the contents of a file before updating (hereinafter referred to as an image) in another file in a storage device in advance, and when updating the file, a transaction is performed. At the end of the process, the transaction process is approved and the file updated by the process is set as a new file and the saved pre-update image is discarded. On the other hand, due to the denial of transaction processing performed when deadlocks among multiple processes of a transaction, device failure or software failure, or cancellation of all record updates in progress due to transaction processing interruption, etc. The pre-updated image is written to a file, and the state of the file before the start of transaction processing is restored.

[0003]

The above-mentioned conventional file recovery control method, when the contents of a file are updated in order to restore the contents of the file to the state before the transaction processing is started, the update just before the update is performed. The previous image must be stored and stored in a separate file. In addition, since multiple transactions operate at the same time, the pre-update image must be logically associated and uniquely referenced for each transaction, and saved after file recovery due to transaction process approval or rejection. The related pre-update image must be discarded, the data input / output processing to / from the auxiliary storage device or the mass storage device that stores the file is increased, and the file capacity for storing the pre-update image is not fixed. It has the drawback of being leprosy.

[0004]

A file recovery control system of the present invention is a file recovery control system of an electronic computer system for transferring file update data in transaction processing units between a main storage device and a file of an external storage device. In, each record has two images,
One image holds the image before update and the other image holds the image after update at the same time, and which image is the latest approved image according to the value of the bit corresponding to each record of this file Referring to the bitmap provided in the main storage device, the access information of the transaction provided in the main storage device for registering the identification information of the file and the record updated during the transaction, and the bitmap. A search means for searching and outputting the latest image of the record, and updating the record by rewriting the image indicating that the bit of the bitmap is not the latest approved image when updating the record, and accessed the access information. Update method to register the record identifier and transaction record The approval processing means for inverting the value of the bit of the bitmap corresponding to the record accessed by the transaction by approval of the update processing, and the access information corresponding to the file accessed by the transaction are discarded and the corresponding bitmap is not changed. It has a denial processing means.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention.
The embodiment shown in FIG. 1 comprises a main storage area 1, an external storage area 2, a record retrieval section 3, a record update section 4, a transaction approval processing section 5, and a transaction denial processing section 6, and the main storage area 1 is transaction access information. 11
And a bitmap 12, and the external storage area 2 has a bitmap 21 and a file area 22.

FIG. 2 is a diagram showing the configurations of the bitmap 12 and the file area 22 of FIG. File area 22
The bit map 12 and the bit map 12 usually have a plurality of file areas and a bit map corresponding to each file area as a system, but only one is shown for simplicity of description. The file area (file) 22 is composed of a plurality of records, and each record has two images. For example, the record R80 has a first image 221 and a second image 222. On the other hand, the bitmap 12 has a bit corresponding to each record of the file 22. For example, record R
0, R1, to R80 corresponding to bits B0 and B, respectively
1 to B80. If the bit of the bitmap 12 is "0", the latest correct data is stored in the first image of the corresponding record, and if the bit is "1", the latest image of the second image of the corresponding record is stored. It indicates that the correct data is stored. For example, if the bit B80 is “0”, the record R80
The first correct image data 221 stores the latest correct data.

FIG. 3 shows transaction access information 11
In general, the system has a plurality of transaction access information, but FIG. 3 shows one configuration. The transaction access information is provided for every updated file from the start of a transaction until the end of the transaction. The file identifier 111 in which the file identifier is registered is the head, and the identifiers of all the updated records are in order. The first record identifier 112, the second record identifier 113, ... Are registered.

FIG. 4 is a flow chart of the process of the record update unit 4 of FIG. 1. The process of the record update unit 4 will be described with reference to FIG. When the record update input 41 receives a record update request from the outside, it is checked whether the bit of the bitmap 12 corresponding to the requested record is "1" (step 401). Next, the first and second images of the requested record are read from the file area 22 (step 40
2, 405) The bit read in step 401 is "0"
If so, the record to be updated is transferred to the second image and written (step 403). If the bit read in step 401 is "1", the record to be updated is set to the first
The image is transferred and written (step 406). Next, the file identifier and the record identifier of this record are written in the transaction access information 11 in order (step 404). When accessing the same record by processing the same transaction, the record identifier is not registered in the transaction access information. Further, the access to the same record that one transaction is processing from the processing of another transaction is made to wait until the processing of one transaction is completed by the exclusive control.

FIG. 5 is a flow chart of the process of the record search unit 3 of FIG. 1. The process of the record search unit 3 will be described with reference to FIG. When the record search input 31 has a record search request from the outside, it is checked whether the bit of the bitmap 12 corresponding to the requested record is "1" (step 301). When the bit is "0", the first image of the corresponding record in the file area 22 is read, and the read data is sent to the request source (step 302). When the bit is "1", the second image of the corresponding record is read and this data is sent to the request source (step 30).
3).

FIG. 6 is a flow chart of the processing of the transaction approval processing unit 5. The processing of the transaction approval processing unit 5 will be described with reference to FIG. When an instruction to approve the data update between transactions of the transaction is input from the transaction approval input 42, a series of record identifiers 112, 11 is referred to by referring to the transaction access information 11 registered by this transaction.
The value of the corresponding bit of the bitmap 12 corresponding to 3 to is returned (step 501). Next, in preparation for a system failure such as power failure, the bitmap 12 in the main storage area 1 is written in the bitmap 21 in the external storage area 2 (step 50).
2). Next, assuming that all processing of the transaction is completed, the data of the transaction access information 11 registered in the transaction is cleared (step 5
03).

To explain the processing of the transaction denial processing unit 6, when the transaction denial input 43 inputs an instruction to deny the data update between transactions, the transaction access information 11 registered by this transaction is deleted. All the data of the file identifier 111, the first record identifier 112, ... Are cleared. Therefore, the bitmap 12 corresponding to the file area 22 maintains the state before the processing by the transaction is started.

In the above embodiment, each record of the file area (file) is divided into the first image and the second image, one image is made to hold the data immediately before the start of transaction processing, and the other image is made to hold. Although the update data being processed is stored in, the file is divided into the first file and the second file, and the data immediately before the transaction processing is started is stored in one of the records at the same position. The update data being processed is stored in the other record, and which file side of the record holds the data immediately before the processing is started is displayed by the value of the bit corresponding to the bitmap record. As shown in FIG.
The same processing as in the above embodiment can be performed.

[0014]

As described above, according to the present invention, two kinds of images are provided in the record of the file, the update data is stored in the image which is not the latest specified by the bitmap when the record is updated, and it is confirmed by the transaction processing. Alternatively, by confirming the designation of the bitmap by denial, there is an effect that file recovery control can be performed quickly and easily.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a bitmap and a file area in FIG.

FIG. 3 is a configuration diagram of transaction access information of FIG. 1.

FIG. 4 is a flowchart of processing of a record update unit in FIG.

5 is a flow chart of processing of a record search unit in FIG.

6 is a flow chart of processing of a transaction approval processing unit in FIG. 1. FIG.

[Explanation of symbols]

 1 main storage area 2 external storage area 3 record search section 4 record update section 5 transaction approval processing section 6 transaction denial processing section 11 transaction access information 12, 21 bitmap 22 file area 31 record search input 41 record update input 42 transaction approval input 43 Transaction denial input 111 File identifier 112 First record identifier 112 Second record identifier 221 First image 222 Second image B0, B1, ~ B80 bit R0, R1, ~ R80 record

Claims (1)

[Claims] 1. A file recovery control method of a computer system for transferring file update data in transaction processing units between a main storage device and a file of an external storage device, wherein each record has two images. , One file holds the image before update and the other image holds the image after update at the same time,
A bitmap provided in main storage which indicates which image is the most recently approved image by the value of the bit corresponding to each of the records in this file,
Retrieval means for retrieving and outputting the latest image of the record by referring to the access information of the transaction, which is provided in the main storage device for registering the identification information of the file and the record updated during the transaction of the transaction, and the bitmap. And a updating means for updating the record by rewriting the image indicating that the bit of the bitmap is not the latest approved image at the time of updating the record, and registering the identifier of the record that accessed the access information, and the transaction record Approval processing means for inverting the value of the bit of the bitmap corresponding to the record accessed by the transaction by approval of the update processing,
A file recovery control method comprising: a denial processing unit that discards access information corresponding to a file accessed by a transaction and does not change a corresponding bitmap.