JPH0476744A - Computer system with shared memory table recovering function - Google Patents

Abstract

PURPOSE:To improve the productivity, maintenance and operability of an application program for accessing a shared table by providing the computer system with a memory filing means for simulating a disk file interface. CONSTITUTION:The computer system is provided with the memory filing means 1 for simulating the disk file interface, a data base recovering means 2 for executing data base recovery control, a shared memory table 3, a data base file 4, and the application program 5. Since a means for allowing the table 3 in a storage device to pretend to be a file in a magnetic disk device, i.e. the memory filing means 1 for simulating the disk file interface, is used, the contents of the table 3 can be held at an always matched state with a data base without requiring a specific means in each user. Consequently, the productivity, maintenance and operability of the application program for accessing the shared memory table 3 can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a computer system having a database recovery function, and more particularly to a computer system having a shared memory table recovery function.

[Conventional technology]

A conventional computer system having a database recovery function does not have a function to automatically match the contents of a shared table held in a storage device with the contents of a database file held in a magnetic disk device.

[Problem to be solved by the invention]

In a computer system with a conventional database recovery function, when a program is aborted, a file is created between the database file held in the magnetic disk device undergoing recovery processing and the shared table in memory in the storage device that is not undergoing recovery processing. , an inconsistency occurs. Therefore, it is necessary to periodically restore shared tables that have been updated in the middle using special means determined for each user, which improves the productivity, maintainability, and operability of application programs that access shared tables. There was a problem above.

[Means to solve the problem]

A computer system with a shared memory table recovery function of the present invention is a computer system having a database recovery function, in which a memory table on a storage device is converted into a file on a magnetic disk device by simulating a disk file interface of a magnetic disk device. and a database recovery means that performs data recovery control without distinguishing between the database file on the magnetic disk device and the memory table in which the disk file interface is simulated.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a functional block diagram of one embodiment of the present invention,
A memory file conversion means 1 that simulates a disk file interface, a database recovery means 2 that performs database recovery control, a shared memory table 3,
It has a database file 4 and an application program 5.

FIG. 2 is a diagram showing an example of the configuration of a memory filing management table 20 built into the memory filing means 1. As shown in FIG. The number of records in the management table is (2”-1) = 2
It is set at 55. Each first record of the memory filing management table 20 holds shared memory table information. Then, a table name field 21, a record length field 22, a record number field 23,
Shared memory table management section location field 24
and a shared memory table main body location field 25.

FIG. 3 is a diagram showing an example of the configuration of the shared memory table 3. The shared memory table 3 has a configuration that simulates the disk file interface of an actual magnetic disk device, and consists of a shared memory table management section 31 and a shared memory table main body section 32. The shared memory table management unit 31 stores a disk name, disk ID, number of cylinders, number of tracks, and number of sectors as disk device management information, and stores a file name 2 storage location, size, and attributes as file management information. ing. The shared memory table body section 32 contains the original contents of the memory table to be shared, and corresponds to files only included in the simulated disk device.

FIG. 4 is a flowchart showing the processing procedure by which the memory file creation means 1 creates the shared memory table 3.

Shared memory table creation processing starts (step 4)
1), the memory file creation means 1 analyzes the specified parameters at startup (step 42). Then, the designated parameter value is stored in the table name field 21, record length field 22, and record number field 23 of the i-th record of the memory file management table 20 (step 43). Next, check the memory area of shared memory table 3 according to the specified record length and number of records,
Necessary information is stored in the shared memory table management section 31, and all values of the contents of the shared memory table main body section 32 are initialized to zero (step 44). Next, store the values of the shared memory full management section location field 24 and the shared memory table main body location field 25 of the memory file management table 20 (step 45),
Ending the shared memory table creation process (step 46
).

FIG. 5 is a diagram showing an example of the relationship between the memory file management table 20 and the shared memory table 3 after the shared memory table creation process is completed.

The shared memory table management section location field 24 of the memory filing management table 20 corresponds to the shared memory table management section 31 of the shared memory table 3, and the shared memory table body section location field 25 and the shared memory table body section 32 correspond to each other. There is. The deletion of the shared memory table 3 is automatically performed when the shared memory table creation process of the memory file creation means 1 is completed.

FIG. 6 is a flowchart illustrating the database access processing procedure performed in response to a request from the application program 5. At the beginning of the database access process (step 61), the application program 5 issues a database access request (input) to the database recovery means 2.

Output request) is made (step 62). The database recovery means 2 performs access preprocessing (step 63), then issues a file I10 request to the relevant disk device, and identifies the disk device (step 6).
4). If the relevant disk device is an actual magnetic disk device, normal file I10 is performed in database file 4 (steps 65 to 67). If the disk device is the memory filing means 1, the shared memory table 3 is accessed via the memory filing means 1 (steps 70 to 72). In any case, the database file 10 result notification is returned to the database recovery means 2 (step 67 or 72). The database recovery means 1 then performs post-access processing (step 68), and the database access ends (step 69).

[Effects of the Invention As explained above, the present invention provides a means for making a shared memory table on a storage device appear to be a file on a magnetic disk device, that is, simulating a file interface in a computer system having a database recovery function. By introducing the memory file conversion means, the contents of the shared memory table can always be kept consistent with the database without requiring special measures for each user. This reduces the productivity of application programs that access shared memory.

This has the effect of improving maintainability and operability.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram of one embodiment of the present invention, FIG. 2 is a diagram showing an example of the configuration of a memory file management table, and FIG.
The figure shows an example of the configuration of a shared memory table, FIG. 4 is a flowchart showing the procedure for creating the shared memory table in FIG. 2, and FIG. 5 shows an example of the relationship between the memory file management table and the shared memory table. , FIG. 6 is a flowchart showing the database access processing procedure performed in response to a request from an application program. 1...Memory file conversion means, 2...
Database recovery means, 3... Shared memory table, 4... Memory file conversion means, 5.
...Application program, 20...
...Memory file management table, 21...
Table name field, 22...Record length field, 23...Number of records field, 24
. . . Shared memory table management section location field, 25 . . . Shared table body section location field, 31 . . . Shared memory table management section, 32 . . . Shared memory Table main body. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] In a computer system having a database recovery function, a memory file conversion means for making a memory table on a storage device appear to be a file on the magnetic disk device by simulating a disk file interface of the magnetic disk device; A computer system with a shared memory table recovery function, comprising: a database recovery means that performs data recovery control without distinguishing between a database file and the memory table in which the disk file interface is simulated.