JPH04363733A - Abnormality discrimination system for shared database - Google Patents

Abstract

PURPOSE:To exactly, speedily, and easily discriminate the generation of the abnormality of a shared database from the origin of access. CONSTITUTION:As for the processing of performing an access to a shared database 3 from the plural origins of access which are operated on the same data and time, a lock file 4 prepared when the database 3 is used by one of the origins of access (terminals E1, E2,..., En), and a data and time data registering part 42 provided in the lock file 4, are prepared. When one of the terminals E1, E2,..., En performs an access to the database 3, the data and time data in the data and time data registering part 42 are updated in a cycle alpha, and when an access request is generated from an another origin of access, the registered data and time data are compared with the present data and time data, and when a time difference is beyond the cycle alpha, the abnormality of the database is judged.

Description

[Detailed description of the invention]

0001 [Purpose of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for determining abnormalities in a shared database, which makes it possible to quickly determine the occurrence of an abnormality in a database when the shared database is accessed from a plurality of access sources.

0003

2. Description of the Related Art In order to access a shared database from a plurality of access sources such as multiple processes or terminals, exclusive control has conventionally been implemented. According to this exclusive control, when any access source accesses a shared database, a so-called lock file is created to indicate that this database is in use. While this lock file is being created, access requests from other access sources are excluded or kept in a waiting state, and when the access ends and the lock file is deleted, the access requests from other access sources are It accepts access requests.

By the way, if some kind of failure or abnormality occurs in the access processing of the shared database, the lock file may remain without being deleted even though the access processing has been completed.

[0005] When such a situation occurs, according to the conventional method of determining whether a database is in use based on the presence or absence of a lock file, other access sources simply see that the database is in use. It was not possible to determine whether the database was abnormal or not.

[0006]

[Problem to be Solved by the Invention] As described above, according to the above-mentioned conventional exclusive control, it is determined whether or not the database is in use based on the presence or absence of a lock file, so the database becomes abnormal. In some cases, it is not possible to determine the abnormality from other access sources, and the problem is that the database remains in the "in use" state forever, and the occurrence of an abnormality in the database cannot be detected quickly, resulting in a long recovery process. It was supposed to require.

The present invention has been made in view of the above circumstances, and its purpose is to provide a shared database abnormality determination method that can accurately, quickly and easily determine the occurrence of an abnormality in a shared database based on the access source. There is a particular thing.

[0008] [Structure of the invention]

[0009]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a process for accessing a shared database from a plurality of access sources operating on the same date/time, in which the database is accessed by one of the access sources. The lock file created if it is used by the original,
and a date/time data registration section provided in this lock file, and while the database is being accessed from any access source, the date/time data in the date/time data registration section is updated at a cycle α. In addition, when an access request occurs from another access source, the registered date/time data and the current date/time data are compared, and if the difference exceeds the period α, an error is detected in the database. It is characterized by determining that.

0010

[Operation] When the shared database is being used by any access source, a lock file is created and the current date/time data is registered in the date/time data registration section. During access to the shared database, the date/time data in the date/time data registration section is updated and rewritten at intervals of α. In this state, if an access request occurs from another access source, the registered date/time data and the current date/time data are compared, and if the difference exceeds the period α, the database It is determined that some kind of abnormality has occurred. This allows other access sources to quickly learn of the occurrence of an abnormality in the shared database.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of an embodiment of a device to which the shared database abnormality determination method according to the present invention is applied.

As shown in the figure, a plurality of terminals E1, E
2 , ..., En are connected to the shared database 3 via the input/output section 1 and the access management section 2 so as to be accessible. Also, any terminal E1, E2,..., En
The lock file 4 is provided with a lock file 4 that is created when an access request is generated from a user, and this lock file 4 includes a used file name registration section 41 that registers the file name in use.
and a date/time data registration unit 42 for rewritably registering the date and time.

The access management section 2 includes an access section 21 that accesses the database 3 in response to an access request from one of the terminals E1, E2,..., En, and an access section 21 that accesses the database 3 in response to an access request from one of the terminals E1, E2,..., En. A lock file management unit 22 that creates a lock file 4 when an access request occurs and deletes the created lock file 4 when the access request ends, and registers the date/time data using the date/time data supplied from the terminal. A date/time data updating section 23 rewrites the date/time data in the section 42 at a predetermined cycle α, and a date/time data updating section 23 that updates the date/time data in the date/time data registration section 42 with the current date/time data. It also includes a comparison/determination unit 24 that notifies the occurrence of an abnormality in the database 3 when the difference time is equal to or greater than the period α.

Next, the operation of this embodiment will be explained based on the flowcharts of FIGS. 2 and 3.

[0015] Any terminal E1, E2,..., En
When an access request occurs from (step ST1)
, the lock file management unit 22 checks whether the lock file 4 has been created. If the lock file 4 has not been created (step ST2 NO), a lock file is created, the file name to be used is written in the file name registration section 41, and the current date/time data supplied from the access source terminal is /Time data registration section 4
2 (steps ST3, 4), access processing is started (step ST5). Each time a predetermined cycle α arrives during access, the date/time data registration unit 42 uses date/time data supplied from the accessing terminal.
The data within is updated (steps ST6, ST7). When the access from a certain terminal ends, the lock file 4 is deleted (steps ST8, ST9).

On the other hand, in step ST2, if the lock file 4 has already been created, the process advances to step ST10 in FIG. Data registration section 4
2 and the date/time data TM stored in 2 (step ST10).

If the difference time between the current data T and the stored data TM is smaller than the predetermined period α (step ST11Y
Since the database 3 is currently being used by another terminal, the ES) notifies the accessing terminal of this fact (step ST12). If the difference between the current data T and the stored data TM is greater than the predetermined period α (step ST
11NO) means that lock file 4 exists even though the access from the terminal has ended, so it is determined that an error has occurred in database 3 and the accessing terminal is notified of this fact. (Step ST13).

As described above, according to this embodiment, the occurrence of an abnormality in the database can be quickly detected, and the database repair process can be performed quickly. therefore,
By quickly detecting the occurrence of an abnormality in the database 3, it becomes possible to collect data in the database 3 from the terminal, investigate the cause of the abnormality, and automatically repair the database 3.

In this embodiment, the date/time data is supplied from the accessing terminal, but it may also be supplied from the access management section 2 on the database side.

[0020]

[Effects of the Invention] As explained above, according to the present invention, when accessing a shared database, it is possible to accurately, quickly and easily know whether the shared database is being used by another accessor or whether an abnormality has occurred in the shared database. Can be done. Therefore, it is possible to eliminate the conventional problem of waiting for a long time after being determined to be in use, and also to be able to quickly learn of the occurrence of an abnormality, so that repair work can be performed quickly.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a device to which the method of the present invention is applied.

FIG. 2 is a flowchart illustrating the operation of the system of the present invention.

FIG. 3 is a flowchart illustrating the operation of the system of the present invention.

[Explanation of symbols]

1 Input/output section 2 Access management department 3. Shared database 4 Lock file 21 Access section 22 Lock file management department 23 Date/time data update section 24 Comparison/judgment section 41 Used file name registration section 42 Date/time data registration section

Claims (1)

[Claims] Claim 1: In the process of accessing a shared database from multiple access sources operating on the same date/time, a lock file that is created when the database is used by any of the access sources; and a date/time data registration section provided in a lock file, and while the database is being accessed from any access source, the date/time data in the date/time data registration section is updated at a cycle α. When an access request occurs from another access source, the registered date/time data and the current date/time data are compared, and if the difference exceeds the period α, it is determined that the database is abnormal. An abnormality determination method for a shared database characterized by determining.