JPH0962554A - Quiescent point save generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a need of preserving the update contents by generating a quiescent point save, which reflects contents of update performed during saving, just after saving in the case of saving a database in parallel during database update execution. SOLUTION: When a request for saving during execution is issued from a terminal equipment 4, a means 5 for saving during execution requests a data management means 1 to start a journal and saves a data base 3 in a save 6 and requests the data management means 1 to terminal the journal and requests a quiescent point saving means 8 to save a quiescent point. At this time, the quiescent point saving means 8 takes records as input from a journal 7 and sorts inputted records in the descending order of update times and in the ascending order of record numbers and matches them with the save 6 to generate the state of the data base at a point of time, when consistency is secured, as a quiescent point save 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE _{INVENTION 1. Field of the} Invention The present invention relates to a stationary point save creation method, and more particularly to a stationary point save creation method during data update.

[0002]

2. Description of the Related Art Conventionally, this type of save creation method has been used for the purpose of eliminating the suspension of the work referring to the file by creating the latest backup using the old backup file and the update log file. Has been.

For example, Japanese Patent Laid-Open No. 02-039252 discloses a backup generation means, a user instruction input means, an update log file, a backup information extraction means, an old backup file, and an update information extraction means.
By using the update information file, the backup information editing means, and the new backup file, by inputting the update information extraction instruction from the user instruction input means, the new backup file can be executed without stopping the work referring to the file. Describes the technology to output the latest backup information.

[0004]

When a database is saved in parallel while the database is being updated, a time lag is included in the database if the database is restored from this save. As a result, regarding the update processing performed during the save, the updated part and the unupdated part exist in the database, and the reference consistency of the entire database cannot be guaranteed.

[0005] For this case, to obtain the status of the database at a stationary point of the integrity of the guaranteed one reference, _{the following}
There are _challenges . (1) updates that have been made during the execution must be saved as a journal, _there is a problem in operability. (2) It is necessary to reflect the contents of the update made during the execution of the save after restoring from the save, which causes a problem in operability and operability.

_{An object of the present invention is to} save the update contents executed during execution as a journal by creating a save reflecting the update contents executed during the save execution immediately after executing the save. _{eliminating the} need _{is to} eliminate the need to reflect the updates that were made during the save execution after restoring from the save.

[0007]

According to the still point save creation method of the present invention, when a data update request is issued from an application program, the update request content is saved in an update request content buffer, and the application program sends a data commit request. journal and time when an update request content of the same application program performing _the update request contents when transferring from the buffer to the database with the contents of the record that has been updated if in the journal started simultaneously with the update record number updating process when done When a journal start request is made from the save means during execution,
And data management means for the journal starting in Wait journal end request is made from _the running saving unit, when executing the save request is made from the terminal device, and a journal start request for the data management unit, save To the data management means, a journal end request to the data management means, and a quiesce point save request to the quiesce point saving means, and a quiesce point save request from the running save means. To
Enter a journal, sort the records entered in descending order of the update time and sort them in ascending order of the record number, and compare them with a save. And a stationary point saving means for creating the above state as a stationary point saving.

[0008]

BEST _{MODE FOR CARRYING OUT THE INVENTION Next,} a description _{with reference} to the drawings, _{embodiments of the} present invention.

FIG. 1 is a block diagram showing the configuration of an _embodiment of the present invention. _This quiesce point save creation method is a data management means 1, an update request content buffer 2, a database 3, a terminal device 4, a running save means 5, a save 6, a journal 7, and a quiesce point saving means 8. And still point save 9 and application programs 11 and 1
2, ..., _{and a} 1n.

When the data management means 1 receives a data update request from the application programs 11 to 1n, it stores the update request content in the update request content buffer 2. Further, when there is a data commit request from the application programs 11 to 1n, the update request content of the same application program is read from the update request content buffer 2 and written in the database 3, and the update request content from the same application program is updated request content. If it is deleted from the buffer 2 and the journal is being started, the updated contents, the update record number, and the time when the update process is performed are stored. Further, the period from when the journal start request is issued by the running save means 5 to when the journal end request is issued is referred to as the journal start.

The executing save means 5 is a journal start request to the data managing means 1, a saving of the database 3 to the save 6, and a journal to the data managing means when the executing save request is issued from the terminal device 4. A termination request and a stationary point saving request to the stationary point saving means 8 are issued.

The quiesce point saving means 8 enters the journal 7 when the quiesce point saving request is issued from the executing save means 5, and inputs the entered records in descending order with respect to the update time.
Sort and rearrange the record numbers in ascending order, and match this with save 6. At this time, with respect to the record in which the record number appears once or more, only the record having a large update time is matched. When the data of the same record exists in both, the record of the journal 7 is written in the stationary point save 9 when the data of the same record does not exist in both.

Next, a book constructed in this way
_{The operation of the embodiment} will be described.

FIG. 2 shows the initial state at time t0 and time t.
1, the state of the database at time t2 and time t3 (t1 <t2 <t3) is shown. The content of the record number of the record number n in the database in the initial state is r (n, 0). At time t1, the application program m1 makes a data update request and a data commit request for the records having record numbers 1, 2, and 5, and the contents of the records are r (1, t1), r (2, t1), and r, respectively.
It is assumed that it becomes (5, t1). Further, at time t2, the record numbers from the application program m2 are 2, 3,
A data update request and a data commit request regarding the record number of 6 are made, and the contents of the record are r
It is assumed that (2, t2), r (3, t2) and r (6, t2) are obtained. Further, at time t3, the application program m3 makes a data update request and a data commit request for the records with record numbers 2, 4, and 7,
The contents of the record are r (2, t3), r (4, t
3), r (7, t3).

When a running save request is issued from the terminal device 4 at time t0, the running save means 5 operates as _follows . (1) A journal start request is issued to the data management means 1. (2) Save the database 3 to the save 6. (3) A journal end request is issued to the data management means 1. (4) A stationary point saving request is issued to the stationary point saving means 8.

As a result, for example, the above (1) is t0.
_When (2) is performed from time t0 to time t2 ′ _, (3) is performed at time t2 ′, and (4) is performed at time t3 (t0 <t
1 <t2 <t2 '<t3), the contents of the save 6 and the journal 7 are as shown in FIG. 3 at time t2'.

When there is a stationary point save request from the executing save means 5, the stationary point save means 8 operates as _follows . (1) Sort the input records in descending order of update time and in ascending order of record numbers. As a result, the quiesce point saving means 8 internally has the data of the sorted journal information of FIG. (2) The save 6 and the sorted journal information are matched. With respect to the sorted journal information, only records having a large update time are matched with records in which the record number appears once or more. If the data of the same record exists in both, the record of the journal 7 is written, and if the data of the same record does not exist in both, the record of save 6 is written in the quiesce point save 9.

[0018] As a result, the still point save 9 becomes the state of the database at t2, the still point save by _Ru can get.

[0019]

As is apparent from the above _description ,
_{According to the present invention,} it is necessary to save the update contents made during execution as a journal by creating the quiesce point save that reflects the update contents made during the save execution immediately after executing the save. _{the lost,} it is possible to eliminate the need to reflect the updates that were made during the save execution after restoring from the save, is _to improve reliability and operability.

[Brief description of drawings]

FIG. 1 is _a block diagram of an _{embodiment of the} present invention.

2 is a diagram showing a state of the database for each timekeeping _to the embodiment _{of FIG.}

FIG. 3 is a diagram showing contents of save and journal at time t2 ′ in the embodiment of FIG.

4 is a diagram showing sorting of journals by the quiesce point saving means in the embodiment of FIG. 1. FIG.

FIG. 5 is a diagram showing saving by a stationary point saving means and journal matching in the embodiment of FIG.

[Explanation of symbols]

 1 data management means 2 update request content buffer 3 database 4 terminal device 5 running save means 6 save 7 journal 8 quiesce point save means 9 quiesce point save

Claims (1)

[Claims] 1. A stored when the data update request from the application program is performed an update request content update request content buffer, _the update request contents of the same application program when the data commit request is made from the application program When the journal is being started at the same time as the journal is being transferred from the update request content buffer, the contents of the updated record, the update record number, and the time at which the update process was performed are stored in the journal, and the journal start request is sent from the running save means. and data management means for the Wait cracking journal end request from _said executing saving means if it is performed as in starting a journal, when executing the save request is made from the terminal device, starts the journal for said data management means Database to request and save Save, a journal end request to the data management means, a quiesce point save request to the quiesce point save means, a running save means, and a journal when the quiesce point save request is issued from the running save means The state of the database at one quiescent point where the consistency is guaranteed by entering and sorting the entered records in descending order of the update time and ascending order of the record number, and matching this with save. And a static point saving means for creating a static point save as a static point save.