JPH08328946A - Managing method for secondary storage area - Google Patents

Abstract

PURPOSE: To read the managing information of a secondary storage area inside a secondary storage device into a main storage area at high speed. CONSTITUTION: This method is provided with an area 3d dedicated for management information for storing the management information containing an address 3b of a free storage area arranged on a secondary storage area 3a inside a secondary storage device 3 and a size 3c of the free storage area while physically continuing it for the unit of prescribed quantity and when managing the free storage area in a data area inside the secondary storage device while using the management information in the area 3d dedicated for management information, the management information in the area 3d dedicated for management information is read into a main storage device 2 as management information 2a and reconstructed into a desired data structure so that the free storage area can be managed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary storage area management method for managing an empty storage area in a secondary storage area in an electronic computer system, and more particularly to an empty storage area in a secondary storage device in a database management system. Manage 2
The present invention relates to a method of managing the next storage area.

[0002]

2. Description of the Related Art In a multimedia database or the like, which has been attracting attention in recent years, not only simple data such as numerical values and character strings that have been conventionally stored in the database but also variable length and large data such as image data and document data are used. A large amount of data is stored in the database. In this case, in order to handle these long and large amount of data efficiently, 2
It is necessary to handle area information such as empty storage information in the next storage area at high speed.

On the other hand, as a conventional method of managing the free storage area of the secondary storage area, a method of managing the free storage area by linking it with a pointer is known. However, in this management method, since the pointer is sequentially followed to search for a free storage area, it takes access processing time and the free storage areas are often connected discontinuously. There is a problem that it is easy to store the data by dividing it into discrete positions in the storage area.

In order to solve this problem, for example, Japanese Patent Laid-Open No. Hei 2
In Japanese Patent Publication No. 98752, there is described a secondary storage area management method using a binary tree in which an entry of an empty storage area with an address as a key is registered in the binary tree to manage the empty storage area. Without accessing real data,
The free storage area can be searched at high speed.

[0005]

By the way, in order to manage the secondary storage area, it is necessary to store the area information of the secondary storage area also in the secondary storage area, and actually manage the area. When performing the above, it is necessary to read the area information from the secondary storage device into the main storage area.

Therefore, even if the secondary storage area management method disclosed in Japanese Patent Laid-Open No. Hei 2-98752 is used, it is necessary to read the area information of the secondary storage area into the main storage area.

Considering the case of performing secondary storage area management by the secondary storage area management method disclosed in Japanese Patent Laid-Open No. 2-98752, management is performed as actual data is frequently generated and deleted. The number of free storage areas to be increased successively increases, and as a result, the entries required for managing the free storage areas are sequentially generated. Further, in the secondary storage area, since the actual data is also generated from the generation of a certain area management entry to the generation of the next area management entry, the next area management entry is set to 2 When writing in the next storage area, the area management entry is stored in physically discrete locations.

Therefore, when the entire area management entry stored in the secondary storage area is read into the main storage area, it is necessary to read many area management entries in physically discrete locations, which results in In addition, there is a problem that the process of reading the entry for managing the entire area from the secondary storage area into the main storage area becomes slow.

Therefore, the present invention eliminates such problems,
An object of the present invention is to provide a secondary storage area management method capable of reading management information of a secondary storage area in a secondary storage device into a main storage area at high speed.

[0010]

The present invention is a secondary storage area management method for managing an empty storage area in a secondary storage device in an electronic computer system, wherein the secondary storage area (3a in FIG. 1) is provided. Dedicated to the management information, which physically stores the management information including the address (3b in FIG. 1) and the size (3c in FIG. 1) of the empty storage area to be arranged in a predetermined quantity unit. Management information dedicated area (3 in FIG. 1)
d) is provided, and the free storage area in the secondary storage device is managed by using the management information in the management information dedicated area.

When the management information exclusive area is used up, various conventional techniques can be used, but preferably, a new management information exclusive area is secured and the management information exclusive area is expanded by connecting them by a list. It has a mechanism that enables it.

[0012]

In the present invention, as shown in FIG. 1, management information including an address 3b of a free storage area arranged on the secondary storage area 3a in the secondary storage device 3 and a size 3c of the free storage area. When a data area in the secondary storage area 3a is managed by providing a management information dedicated area 3d dedicated to the management information, which is physically contiguously stored in a predetermined quantity unit, the management information is stored in the main storage device 2. The data area 3e in the secondary storage area 3a is managed by constructing a data structure such as a binary tree using the read management information 2a. As a result, the management information in the secondary storage area can be read at high speed.

[0013]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a diagram showing the configuration of a database management system which is an embodiment of the present invention. In FIG. 2, the database management system is configured by connecting the database management devices 11 and 12 and the database device 13 to the network N.

The database device 13 has a secondary storage area m.
And a data area 13a in the secondary storage area m.
And a management information dedicated area 13b. Data area 13
a is managed by being divided into a plurality of data areas in units of pages. The management information dedicated area 13b is a dedicated area for storing management information for managing the data area 13a.

The database management device 11 has a data management unit 11a, and an area management unit 11b in the data management unit 11a. The area management unit 11b uses the data area 13
When managing a free storage area or the like in a, the management information is read from the management information dedicated area 13b of the secondary storage area m, and the data area 13a is read based on the read management information 11c.
Area management. The data management unit 11a refers to the area management of the area management unit 11b and performs processing such as writing, reading, and deleting data in the data area 13a. The database management device 12 is the database management device 11
It has the same configuration as.

Next, the data structure of the management information dedicated area 13b will be described with reference to FIG. FIG. 3 is a diagram showing the data structure and contents of the management information dedicated area 13b. The management information dedicated area 13b shows a page offset and an empty area within the page for each page in the data area 13a. The management information that includes them is stored as a pair. Each management information is stored in the management information dedicated area 1
In 3b, they are stored physically continuously.

If there is no area for storing new management information in the management information dedicated area 13b, a new management information dedicated area 14b is provided to store new management information. At this time, the address of the new management information dedicated area 14b is stored at the end of the management information dedicated area 13b.

Next, referring to FIG. 4, the area management unit 11b.
The area management performed by will be described. Area management unit 11b
As described above, the management information dedicated area 13b is accessed to read the management information stored in the management information dedicated area 13b, and the read management information is stored in the management information 11
Store as c. Then, the area management unit 11b performs area management based on the read management information 11c.

For example, FIG. 4A shows an array structure constructed based on the read management information 11c with the page offset of each page as an index. Thus, by using the array structure in which the page offset is used as an index, it is possible to efficiently search the free area size of a specific page.

Further, FIG. 4B shows a construction of a binary tree data structure in which the address of an empty area is used as a key based on the read management information 11c. As a result, the free area size of the specific page can be searched efficiently.

In this way, the area management unit 11b constructs a data structure most suitable for management by the data management unit 11a based on the management information 11c read from the management information dedicated area 13b of the secondary storage area. We are trying to manage data efficiently.

Next, referring to the flowchart of FIG.
The management processing procedure of the data management unit 11a will be described.
In FIG. 5, the data management unit 11a is the area management unit 11
Exclusive control is performed on the management information dedicated area 13b in the database device 13 via b (step 101).
This exclusive control (lock control) is performed by the database device 13
Is shared by the database management device 12, so that the area to be read is locked so as not to be updated while the data to be read is being read.

Thereafter, the data management section 11a judges whether or not the exclusive right can be secured by the exclusive control (step 1
02), the processing of step 101 is repeated until the exclusive right can be secured.

When it is determined in step 102 that the exclusive right can be secured, the area management unit 11b reads the management information including the address of the free storage area and the size of the free storage area from the dedicated management information area 13b (step 103). ).
Then, a data structure such as a binary tree using the address of the free storage area or the size of the free storage area as a key is constructed (step 104), and a desired data is constructed based on the management information having the constructed data structure. The address and size of the free storage area are searched, and data management and processing are performed on the data area indicated by the search result (step 10).
5). For example, processing such as data writing, deletion, and reading is performed. After that, it is determined whether or not the free storage area is changed based on the data management (step 106). If the free storage area is changed, the free storage area management information 11c is changed and the changed management information 11c ( (Empty storage area entry) is stored in the management information dedicated area. On the other hand, if there is no change in the management information of the free storage area in step 106, the process proceeds to step 108.

In step 108, the exclusive control process performed in step 101, that is, the lock is released, and this process ends.

Next, referring to the flowchart of FIG.
Management information dedicated area 13b in the database device 13
The area securing process of will be described.

In FIG. 6, the database device 13 is
When management information (free storage area entry) for a new free storage area is generated, it is judged whether or not there is a free area in the current management information dedicated area 13b (step 201). Management information dedicated area 13
The newly created free storage area entry is stored in b (step 202), and this processing ends.

On the other hand, if there is no free area in step 201, it is judged whether or not the secondary storage area m needs to be further expanded (step 203). That is, it is determined whether or not there is an area in the secondary storage area m for securing the new management information dedicated area 14b. As a result, if the expansion of the secondary storage area is not necessary, the allocation for securing the new management information dedicated area 14b is performed (step 205), and if the expansion of the secondary storage area is required, the secondary storage area After expansion (step 204), the management information dedicated area 14b is allocated in step 205.

Thereafter, a new management information dedicated area 14b is set as the last entry of the current management information dedicated area 13b.
The start address of the is stored (step 206). Then, a new free storage area entry is stored in the new management information dedicated area 14b (step 207), and this processing ends.

As described above, in this embodiment, the management information about the free storage area in the data area in the secondary storage area in the database device 13 is stored in the management information dedicated area all together. Therefore, the area management unit 11b in the database management device 11 can read the management information at high speed. In particular, when the database is shared, it is necessary to read the sequential management information each time, so that the effect of being able to read the management information at high speed is great.

[0032]

As described above in detail, according to the present invention, the management information including the address of the free storage area arranged on the secondary storage area and the size of the free storage area is physically allocated in a predetermined quantity unit. The management information dedicated area dedicated to the management information that is continuously stored is provided, and the free storage area in the secondary storage device is managed using the management information in the management information dedicated area. It has an advantage that information can be read at high speed.

In particular, when the secondary storage area functions as a shared database, it is necessary to read new management information every time the database is used, so that the management information can be read at high speed.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of the present invention.

FIG. 2 is a diagram showing a configuration of a database management system that is an embodiment of the present invention.

FIG. 3 is a diagram illustrating a management information dedicated area 13b and its contents.

FIG. 4 is a diagram showing an example of a data configuration in an area management unit 11b.

FIG. 5 is a flowchart showing a management processing procedure of the data management unit 11a.

FIG. 6 is a flowchart showing a process of storing an empty storage area entry in a management information dedicated area in the database device 13;

[Explanation of symbols]

1 ... Central processing unit 2 ... Main storage unit 2a ... Management information
3 ... Secondary storage device 3a ... Secondary storage area 3b ... Free storage area address 3c ... Free storage area size 3d ... Management information dedicated area B ... Network bus

Claims (1)

[Claims] 1. A method of managing a secondary storage area for managing an empty storage area in a secondary storage device in an electronic computer system, comprising: an address of an empty storage area arranged on the secondary storage area; A management information dedicated area dedicated to the management information for physically storing the management information including the size in a predetermined quantity unit is provided, and the management information in the management information dedicated area is used to store the management information in the secondary storage device. A method for managing a secondary storage area, characterized by managing an empty storage area.