JP2903605B2 - File area management processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] Regarding management of a file area shared by a plurality of transactions in a computer, a file area management processing method capable of shortening the exclusive occupation time of the area management information and improving transaction processing efficiency And has an area management table and a data management unit. The area management table corresponds to each of pages of a predetermined size constituting a predetermined storage area, and the first and second pages of each of the pages are provided. The data management unit is configured to selectively display the status of
In response to a processing request from a transaction, if the processing request is a request to allocate the empty page to the transaction, refer to the area management table and select the page corresponding to the first state display In the case of a request to make the allocated page empty, the page specified by the request is selected, and the status display corresponding to the selected page in the area management table is displayed as a second status display The request and a predetermined record indicating the page are stored as a log of the transaction, and when the transaction ends, the status display determined according to the end status and the log is displayed on the page of the area management table. Is configured to be set as the status display corresponding to.

[Industrial applications]

The present invention relates to management of a file area shared by a plurality of transactions in a computer, and more particularly to a file area management processing method for shortening the exclusive occupation time of area management information.

[Conventional technology]

In the computer, for file area allocation management,
In some cases, a storage area of a magnetic disk storage device or the like is divided into areas of an appropriate fixed size to form pages, and the area is allocated in units of pages.
A state such as empty is managed by providing an area management table in which bit information allocated to each page is displayed.

FIG. 3 shows the configuration of a storage device that uses the area management table, which has a data storage unit 1 and a directory unit 2, each of which is composed of the above-mentioned pages, and each page of the data storage unit 1. The data page is used for storing data, and an area management table is configured by associating each bit of each page (hereinafter referred to as an area management table page) of the directory section 2 with each data page. As the value of each bit of the area management table, for example, a bit corresponding to an allocated busy page is turned on, and a bit corresponding to an empty page is turned off.

When a business program for processing a file adds a data record to a file, etc., if there is no area for storing the data record in the existing data page, a new data page acquisition is performed by the data management unit which performs area management. Request. The data management unit receives the processing request, and if it requests the allocation of a new page, sequentially reads the necessary pages of the directory unit 2 to the main memory, and displays the empty state in the area management table. The bit is searched, a data page corresponding to the bit is allocated, the corresponding bit in the area management table is turned on to indicate a busy state, and a data record is stored in this data page.

In addition, when a page that does not store a record is generated due to deletion of a record stored in a file, a processing request to return the page to the system and make the page empty is issued. An area management table page having a bit corresponding to the page designated as "" is read from the directory unit 2 and the bit is turned off to display an empty state.

[Problems to be solved by the invention]

Here, if the computer is a system that manages a so-called transaction as an execution management unit, the processing result such as file update by each transaction will not be transmitted to other transactions for the first time if that transaction has completed processing normally. Also managed to be effective,
When the transaction ends abnormally, it is necessary to make the file save the state before the transaction is executed without making the update etc. in this transaction effective.

For this reason, even when the area management table page read from the directory unit 2 is accessed for a certain transaction, it is occupied by a predetermined exclusive control until the transaction ends and a necessary update is validated. However, there is a problem in that control is performed so as to prohibit another transaction from accessing the same area management table page, and waiting for this access lowers transaction processing efficiency.

An object of the present invention is to provide a file area management processing method capable of shortening the exclusive occupation time of area management information and increasing the efficiency of transaction processing.

[Means for solving the problem]

 FIG. 1 is a flowchart of a process showing the configuration of the present invention.

The figure is a configuration of a file area management processing method, which has an area management table and a data management unit, and the area management table corresponds to each page of a predetermined size constituting a predetermined storage area, The data management unit is configured to selectively display the first and second states of each of the pages, wherein the data management unit receives the processing request from the transaction, identifies the processing request in processing step 10, and If the processing request is a request to allocate the empty page, the processing step 11 refers to the area management table, selects the page corresponding to the first status display, and sets the allocated page to the empty state. In the case of a request to make a state, the page specified by the request is selected in processing step 14, and the state display corresponding to the selected page in the area management table is set as a second state display in processing step 12. In step 13 A predetermined record indicating the page is saved as a log of the transaction, and when the transaction is completed, the status display determined according to the processing steps 15, 16, 19, and the end status and the log determined according to the log, The status display corresponding to the page of the area management table is set in processing steps 16, 17 to 20.

[Action]

According to the processing method of the present invention, only when the area management table is set so that the state of the data page requested to be processed is set to the second state, and only when the area management table is set at the end of the transaction, It is sufficient if there is exclusive control of the required area management table page, and during the intermediate period, the data page being processed is not treated and selected as if it were being used even if it is referenced by other users. Does not cause inconsistency in processing.

〔Example〕

FIG. 2 shows an example of the configuration of a computer, and a transaction
26 is a data management unit 22 for accessing the database 21 stored in a magnetic disk storage device or the like.
Issue a required processing request to advance the processing.

If the process is a data page update process that changes a record on a certain data page of the database 21, adds a record to the data page, or deletes a record, the data management unit 22 Request to read the data page to be updated for update, update the read page,
Is completed, the updated page is written to the database 21. In the case of the above processing, the period from the reading to the writing of the data page is controlled by a known appropriate exclusive control so that another transaction does not access the same data page.

When there is no room to change or add a record in the data page update process and a new page needs to be added, or as a result of deleting a record, there is no record stored in that page and the page is returned If so, the data management unit 22 is requested to allocate or return a page.

In that case, the data management unit 22 reads the required area management table page from the same directory section in the database 21 into the shared memory area 23 as the area management table page 24, and if it is already read, it reads it. Is used to select a free data page, or to perform a process of setting a used data page to a free page, and, similarly to the case of updating the data page, the request source related to the processing of the area management table page. Only when the transaction is normally completed, the area management table page 24 is written to the directory section of the database 21 to complete the update of the area management table, and otherwise recover to maintain the original state.

Here, the area management table includes bits corresponding to each data page of the storage area storing the database 21 in the same manner as described above. According to the present invention, an updating state is added to the meaning of each bit, and the first state is added. For example, the state is set to off, the second state is set to on, and when turned off, it is displayed that "it is not being updated and it is empty", and when it is turned on, it is shown that it is "in use or being updated".

FIG. 1 shows the flow of processing of the area management table by the data management unit 22. When a request from a transaction is received,
In the processing step 10, the processing of the request is identified, and if a page is allocated, in the processing step 11, an off bit is selected from the area management table page read out to the shared memory area, and the corresponding data page is selected from the page number and the bit position. Decide and notify the requesting transaction. If the page is to be returned, in step 14 the area management table page containing the bit corresponding to the data page specified in the request is read into the shared memory area, and if the area management table page has already been read, To determine the bit corresponding to the specified data page.

Next, in the processing step 12, the determined bit of the area management table page 24 is turned on to display the updating state, and in the processing step 13, a record indicating that the data page is to be allocated or returned is recorded. The data is added to the log data collection area 25 of the request source transaction as log data.

At the end of the transaction, the data management unit 22
Processing step 15 identifies whether the transaction has been completed normally or abnormally. If the transaction has been completed normally, processing step 16 refers to the page allocation / return log in the log data collection area 25 of the transaction to process the request. If the page is identified and the page is to be allocated, the corresponding bit of the area management table page 24 is already displayed as being updated, so that it is used to display the busy state. The contents of the area management table page whose update has been determined in this way are reflected in the directory portion at an appropriate time.

In the case of page return processing, the corresponding bit of the area management table is turned on to indicate that updating is being performed in processing step 17, so that it is turned off to display the empty state, and the area management table at the time of normal termination of the transaction due to an abnormality. Finish updating.

In the case of transaction abnormal termination, processing step
In step 19, the request processing and the page are identified from the log, and in the case of page allocation processing, the corresponding bit of the area management table is displayed as being updated, and in step 20 the processing is turned off and the empty state is displayed. return. In the case of the return process, the display of the in-use state is kept as it is, and the process of the area management table ends.

〔The invention's effect〕

As is apparent from the above description, according to the present invention, in managing a file area shared by a plurality of transactions in a computer, the exclusive occupation time of the area management information can be shortened, so that transaction processing can be made more efficient. There are significant industrial effects.

[Brief description of the drawings]

FIG. 1 is a flowchart of a process showing the configuration of the present invention, FIG. 2 is a block diagram showing a configuration example of a computer, and FIG. 3 is an explanatory diagram of an area management table. In the figure, 1 is a data storage unit, 2 is a directory unit, 10 to 17, 19,
Reference numeral 20 denotes a processing step, 21 denotes a database, 22 denotes a data management unit, 23 denotes a shared memory area, 24 denotes an area management table page, 25 denotes a log data collection area, and 26 denotes a transaction.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References “ACOS Software ACOS-4 / MVP XE Data Management Manual”, 7th edition, NEC Corporation, September 1989, p. 228-233 (58) Field surveyed (Int. Cl. ⁶ , DB name) G06F 12/00

Claims (1)

(57) [Claims] An area management table and a data management unit are provided. The area management table corresponds to each of pages of a predetermined size constituting a predetermined storage area, and includes a first and a second page of each of the pages. 2, the data management unit receives a processing request from a transaction, and when the processing request allocates the empty page to the transaction, With reference to the management table, the page corresponding to the first status display is selected (10, 11), and in the case of a request to make the allocated page empty, the page specified by the request is displayed. (14), the status display corresponding to the selected page in the area management table is set as a second status display (12), and a predetermined record indicating the request and the page is stored as a log of the transaction. (13), the transaction is correct When the process is completed (15), the process of the request and the page are identified by referring to the log (16). If the process is a page allocation process, the status display corresponding to the page in the area management table is displayed in the second mode. With the status display setting of
If the page is to be emptied, the status display corresponding to the page is set to the first status display (17). If the transaction ends abnormally (15), a request is made by referring to the log. If the process is to identify the page (19) and make the page empty, the status display corresponding to the page in the area management table is kept at the second status display setting, and the page allocation process is performed. Then, the status display corresponding to the page is set to the first status display (20), and the status display is returned to the status display before the transaction is executed.