JP5358469B2 - Database management method, database management apparatus, database management program, and database management system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate quick table manipulation in terms of operation while suppressing I/O between a database management device and a database device. <P>SOLUTION: Upon receiving a definition request, a processor of the database management device changes table definition information so that a specific table is targeted for special processing. The processor selects an index that is set on the table based on index definition information related to the table, and registers the index in the index definition information so that the index is targeted for special processing. Furthermore, the processor places the index in a specialized memory based on the index definition information while transferring the table from a buffer to the specialized memory based on the table definition information. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a database management method, a database management apparatus, a database management program, and a database management system, and is particularly suitable when applied to a database management system related to a technique using a so-called memory database (memory DB).

  With the development of the information society, many companies offer online services using databases. For example, bank ATM systems and road / railway route search systems are examples of online services. In recent years, with the intensification of competition between companies, each company is expanding its services, extending the service provision time, and providing online services all the time to differentiate themselves from other companies.

  In addition, with the increase in terminals that use online services, such as Internet terminals and mobile phones, the amount of access to online services is increasing. Therefore, for example, in online services that process a large amount of data reference requests from terminals such as road and railway route search services, databases having the same contents are arranged in a plurality of devices, and reference requests from terminals are distributed. Processing. In this way, if a large number of servers are prepared to perform processing by distributing reference requests, the system tends to be expensive.

  In the conventional database management system, since the above-described reference requests are aggregated and processing is performed at a high speed, the price of the memory may drop, and there is no database device that is an external storage device for storing the database. There is a technique for suppressing I / O to an external storage device by placing a memory on top and accessing only data on this memory (hereinafter referred to as “memory DB”) (see Non-Patent Document 1). In the conventional database management system, a table managed by the database of the database device is arranged in the memory DB, so that I / O between the database device and the database management device is suppressed, and the access speed to the database device is low. I make up for it.

Kenneth Salem, Hector Garcia-Molina, “System M: A Transaction Processing Tested for Memory Resident Data”, IEEE Transactions on Knowledge. Vol. 2, no. 1. March 1990

  However, conventionally, in order to realize a high-speed operation on the table, a second database management system for managing the memory DB is introduced and operated and managed separately from the first database management system provided with the database device. There was a need. For this reason, access concentrates on only some of the tables that are operated to implement the online service, so even if it is desired to use the tables as memory DBs, there is a problem that it takes a lot of operational effort. It was.

  The present invention has been made in consideration of the above points, and a database management method capable of easily operating a table at high speed while suppressing I / O between the database management apparatus and the database apparatus, A database management apparatus, a database management program, and a database management system are proposed.

  In order to solve such a problem, in the present invention, a database management method in a database management apparatus for operating the table via a buffer with a database apparatus equipped with a database having at least one table, When the processor of the database management apparatus receives a definition request in which a specific table is specified, a table definition changing step for changing table definition information so that the specific table is a target of special processing; and the specific table When the index is set in the processor, the processor selects the index set for the specific table based on the index definition information regarding the specific table, and the selected index is the target of the special processing. An index determination step for registering in the index definition information so that And a processor that moves the specific table from the buffer to the special memory based on the table definition information, and places the selected index in the special memory based on the index definition information. It is characterized by that.

  According to the present invention, there is provided a database management device that operates a table via a buffer with a database device in which a database having at least one table is mounted, wherein the definition request specifies a specific table. When the definition request is accepted by the definition request accepting unit and the definition request accepting unit, the table definition information is changed so that the specific table is subject to special processing, while the index is set in the specific table. If so, the index definition information is selected so that the index set for the specific table is selected based on the index definition information for the specific table, and the selected index is subject to the special processing. A definition information management unit to be registered in the database, and a database application that accepts access requests to the database device. A buffer for temporarily storing the table when operating the table between the access accepting unit and the database device, a special memory provided separately from the buffer, and the table definition information based on the table definition information A database access control unit configured to move a specific table from the buffer to the special memory, and to place the selected index in the special memory based on the index definition information.

  Further, in the present invention, there is provided a database management program that operates in a database management device that operates the table via a buffer with a database device in which a database having at least one table is mounted, the database management program When a definition request in which a specific table is specified is received by the processor of the apparatus, a table definition changing step for changing the table definition information so that the specific table is subject to special processing, and an index is added to the specific table. If set, the processor is caused to select the index set for the specific table based on the index definition information for the specific table, and the selected index is to be the target of the special processing. An index determination step to be registered in the index definition information; An arrangement step of causing the processor to move the specific table from the buffer to the special memory based on the table definition information, and to place the selected index in the special memory based on the index definition information. It is characterized by making it.

  According to the present invention, there is provided a database management system comprising a database device on which a database having at least one table is mounted, and a database management device for operating the table via a buffer between the database devices. The database management device is configured to receive a definition request in which a specific table is specified, and when the definition request is received by the definition request reception unit, the specific table is subject to special processing. While the table definition information is changed, if an index is set for the specific table, the index set for the specific table is selected based on the index definition information for the specific table and the selected table is selected. Registered in the index definition information so that the index is subject to the special processing. A definition information management unit, a database access receiving unit that receives an access request to the database device, a buffer that temporarily stores the table when operating the table with the database device, and the buffer A special memory provided separately, and the specific table is moved from the buffer to the special memory based on the table definition information, while the selected index is arranged in the special memory based on the index definition information And a database access control unit.

  According to the present invention, it is possible to easily operate a table at high speed while suppressing I / O between the database management device and the database device.

It is a figure which shows the outline of the database management method by 1st Embodiment. It is a block diagram which shows schematic structure of the database management system in 1st Embodiment. It is a declaration sentence which shows an example of the definition request | requirement for making memory DB. It is a figure which shows an example of table definition information. It is a figure which shows an example of index definition information. It is a flowchart which shows an example of the procedure contained in memory DB conversion processing. It is a figure which shows an example of the procedure of memory DB release processing. It is a flowchart which shows an example of the procedure included in memory DB release processing.

  3100: Terminal, 3200: Host computer, 3300: Network, 3400 ... Database management device, 3410 ... Processor, 3420 ... Memory, 3422 ... Definition request accepting unit, 3423 ... Definition information managing unit, 3424 ...... Disk DB management unit, 3425 ... Memory DB management unit, 3426 ... DB access reception unit, 3427 ... DB access control unit, 3430 ... DB buffer, 3440 ... Memory DB, 3441 ... Table, 3442 ... ... index, 3450 ... table definition information, 3460 ... index definition information, 3500 ... database device, 3511 ... table, 3512 ... index.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(1) First Embodiment (1-1) Overview of Database Management Method FIG. 1 shows an overview of a database management method according to the first embodiment. This database management method is realized by executing a database management program in the database management apparatus. In the following description, the database management program represents an executable program, not the program code itself. This database management device is equipped with a processor to be described later, and this processor passes through a so-called DB (database) buffer having a buffering function with a database device having a database having at least one table. And manipulate the table. This database management method includes the following table definition change step, index determination step, and arrangement step.

  In the table definition change step, when the processor receives a definition request in which a table 3441 to be a target of special processing (corresponding to memory DB (database) described later) in the present embodiment is specified, the table 3441 is specially processed. The table definition information is changed so as to be processed (SP100). When this definition request is described in SQL, for example, “ALLOCATE MEMORY TABLE FOR INDEX IDX1” is obtained.

  In the index determination step, when the index 3442 is set in the table 3441, the processor selects the index 3442 set with respect to the table 3441 based on the index definition information with respect to the table 3441, and the selected index 3442 is registered in the index definition information so as to be subject to special processing (SP200).

  In the placement step, the processor moves the table 3441 from the DB buffer 3430 as an example of the buffer to the memory DB 3440 as an example of the special memory based on the table definition information, while the index 3442 selected based on the index definition information. Are arranged in the memory DB 3440 (SP300). In the present embodiment, performing such processing is called “memory DB conversion”. Note that “move” in the present embodiment refers to deleting copy source data after copying a table or data to a copy destination.

(1-2) Configuration of Database Management System in First Embodiment FIG. 2 shows a schematic configuration of the database management system 3000 in the first embodiment. The database management system 3000 includes a database device 3500 and a database management device 3400, and a host computer 3200 and a terminal 3100 are connected to the database management device 3400 via a network 3300. A database management device 3400 is connected to the database device 3500.

  The database device 3500 is provided with a database for managing at least one table. The database device 3500 includes, for example, a magnetic disk device, and a database 3510 is generated in the storage area of the magnetic disk device. The database 3510 manages a large number of data in units of columns and rows for each table 3511. In the first embodiment, such a database on the magnetic disk device is referred to as a “disk database”. In the following description, this disk database is abbreviated as “disk DB”. The structure of the table 3511 is defined by table definition information 3450. In the database 3511, an index 3512 can be set for each table 3511. The structure of the index 3512 is defined by the index definition information 3460.

  On the other hand, the terminal 3100 makes a definition request to the database management apparatus 3400 via the network 3300. The host computer 3200 is a computer on which at least one application (hereinafter also referred to as “user application”) 3210 (corresponding to “UAP” in the drawing) on the user side is operating. The user application 3210 makes a database access request (hereinafter referred to as “DB access request”) to the database management apparatus 3400, and the database management apparatus 3400 operates the table 3511 with the database apparatus 3500.

  On the other hand, the database management device 3400 includes a processor 3410, a bus 3470, a memory 3420, a database buffer 3430, and a memory database 3440. The database management device 3400 includes a network interface (not shown) for connecting to the network 3300. Furthermore, the database management apparatus 3400 may include the table definition information 3450 and the index definition information 3460 described above in a storage unit (not shown). The table definition information 3450 and the index definition information 3460 are not limited to the database management device 3400, but may be stored in other devices, for example, the database device 3500.

  The processor 3410 controls the operation of the database management program 3421 stored in the memory 3420 and controls the entire database management apparatus 3400. The database management program 3421 includes, as its functions, a definition request receiving unit 3422, a definition request management unit 3423, a disk database management unit (hereinafter referred to as “disk DB management unit”) 3424, a memory database management unit (hereinafter referred to as “memory DB management unit”). ”3425, a database access request reception unit (hereinafter referred to as“ DB access request reception unit ”) 3426, and a database access control unit (hereinafter referred to as“ DB access control unit ”) 3427.

  The definition request reception unit 3422 receives a definition request issued by the user application 3210. The definition request management unit 3423 manages the table definition information 3450 and the index definition information 3460, and updates the table definition information 3450 and the index definition information 3460 based on the received definition request.

  The DB access request reception unit 3426 receives a DB access request issued by the user application 3210 and passes it to the DB access control unit 3427. This DB access request is described in so-called SQL.

  The DB access control unit 3427 analyzes the DB access request and controls the disk DB management unit 3424 and the memory DB management unit 3425. The DB access control unit 3427 is normally controlled using the disk DB management unit 3424. However, if there is a definition request, the table 3511 of the DB buffer 3430 is stored in the disk DB management unit 3424 based on the definition request. The table 3441 is generated in the memory DB 3440 and the table 3511 of the DB buffer 3430 is deleted.

  The disk DB management unit 3424 manages the disk DB 3510 of the database device 3500 using the DB buffer 3430 under the control of the DB access control unit 3427. The disk DB management unit 3424 changes the structure of at least one of the table 3511 and the index 3512 of the disk DB 3510 in response to the definition request. On the other hand, the disk DB management unit 3424 adds, updates, or deletes data in the table 3511 of the disk DB 3510 via the DB buffer 3430 in response to the DB access request (hereinafter simply referred to as “operation”). I do. The DB buffer 3430 is a volatile semiconductor memory that can temporarily store data.

  The disk DB management unit 3424 uses the DB buffer 3430 to perform control for exchanging data in the table 3511 with the disk DB 3510 in units of pages that can store a plurality of data records, for example. When an index 3512 is set in this table 3511, the disk DB management unit 3424 operates the table 3511 using this index 3512.

  The memory DB management unit 3425 manages the memory DB 3440 under the control of the DB access control unit 3427. The memory DB management unit 3425 changes the structure of at least one of the table 3441 and the index 3442 of the memory DB 3440 in response to the definition request. On the other hand, the memory DB management unit 3425 adds, updates, or deletes data in the table 3441 of the memory DB 3440 (hereinafter simply referred to as “operation”) in response to a DB access request. When an index 3442 is set in the table 3441, the memory DB management unit 3425 operates the table 3441 using the index 3442. The memory DB 3440 is a volatile semiconductor memory that can temporarily store data.

  As described above, the memory DB management unit 3425 uses the index 3442 in which the index 3512 of the disk DB 3510 is arranged in the memory DB 3440 to control the operation on the table 3441 moved from the DB buffer 3430. Here, the correspondence relationship between the table 3441 and the index 3442 on the memory DB 3440 is defined in the index definition information 3460.

(1-3) Memory DB Definition Request FIG. 3 shows an example of a definition request for creating a memory DB. As the definition request for creating the memory DB, for example, “ALLOCATE MEMORY TABLE T1 FOR INDEX IDX1” can be cited.

  The first part “ALLOCATE MEMORY TABLE” is the first part of the declaration request of the definition request for making the memory DB, and is a declaration for moving the table (for example, the table 3511) existing in the DB buffer 3430 to the memory DB 3440. Part. The second part “T1” is a table name for identifying the table 3511 in the first embodiment. The third part “FOR INDEX” is a declaration part for describing an index to be placed in the memory DB 3440 in accordance with the movement of the table 3441. The fourth part “IDX1” represents the name of the index, and corresponds to the index 3512 (index 3442 after moving to the memory DB 3440) in the first embodiment.

(1-4) Table Definition Information FIG. 4 shows an example of the table definition information 3450. This table definition information 3450 corresponds to the table definition information 3450 shown in FIG. The table definition information 3450 includes specific execution necessity information regarding whether or not it is a target of the memory DB processing for at least one table, and includes a table name and a memory DB conversion flag as column names.

  In the illustrated example, the memory DB flag is “YES” corresponding to the table name “T1”, and the memory necessity information is “NO” corresponding to the table name “T2”. When the memory DB conversion flag is “YES”, it indicates that the setting corresponding to the table corresponding to the table name “T1” is to be converted to a memory DB, while when it is “NO”, The table corresponding to the name “T2” indicates that the memory DB is not set.

  When the processor 3410 receives the definition request, the processor 3410 refers to the table definition information 3450, and based on the memory DB creation flag corresponding to the table specified in the definition request, the processor 3410 may target the table for memory DB creation. Or excluded.

(1-5) Index Definition Information FIG. 5 shows an example of the index definition information 3460. This index definition information 3460 corresponds to the index definition information 3460 shown in FIG. The index definition information 3460 shown in FIG. 5 includes a memory DB flag as specific execution necessity information regarding whether or not it is a memory DB processing target for each at least one table, and includes an index name as a column name, It includes a table name and a memory DB flag. Here, the index memory DB conversion flag in the index definition information 3460 indicates that when the table is converted to the memory DB, the corresponding index created for the disk DB is also converted to the memory DB.

  In the illustrated example, the memory necessity information is “YES” corresponding to the index name “IDX1” and the table name “T1”, and the memory DB is corresponding to the index name “IDX11” and the table name “T1”. The storage flag is “NO”, and the memory DB conversion flag is “NULL (no setting)” corresponding to the index name “IDX2” and the table name “T2”. When the memory DB flag is “YES”, it indicates that the memory DB is set for the table corresponding to the table name and the index name, while when it is “NO”, the table is changed to the table. The table corresponding to the name and index name indicates that the memory DB is not set.

  When the processor 3410 described above receives the definition request, the processor 3410 creates a memory DB for each combination of the table and the index based on the memory DB creation flag corresponding to the combination of the table and the index specified in the definition request. Included or excluded.

(1-6) Specific Processing Content of Memory DB Conversion FIG. 6 shows an example of a procedure included in the memory DB processing. This memory DB processing is executed when the processor 3410 operates each module (such as the definition request receiving unit 3422) of the database management program on the memory 3420. The memory DB processing is executed while the database management apparatus 3400 is operating, that is, online. Here, “online” indicates that a business service that accompanies access to the database is available. The online memory DB makes it possible to enjoy the merit of the memory DB, that is, the high speed without interrupting the use of the business service of the end user.

(1-6-1) Acquisition of Memory DB Targets When performing memory DB conversion, if the terminal 3100 issues a definition request for executing memory DB conversion to the database management apparatus 3400, database management is performed. In the device 3400, the definition request accepting unit 3422 receives the definition request (SP100) and passes it to the definition information managing unit 3423. Here, as a request sentence of a definition request for executing the memory DB conversion (hereinafter also referred to as “memory DB conversion request sentence”), a description as shown in FIG. 3 can be given. The definition information management unit 3423 analyzes the definition request, and acquires the table name that is the object of the memory DB creation from the memory DB creation request statement (SP101). Furthermore, the definition information management unit 3423 acquires the index name to be converted to the memory DB from the memory DB conversion request statement (SP102).

(1-6-2) Table Definition Information Change The definition information management unit 3423 refers to the table definition information 3450 and identifies a table definition information entry corresponding to the acquired index name (SP103). Further, the definition information management unit 3423 changes the memory DB flag of the specified table definition information entry to “YES (performs memory DB)” (SP104).

(1-6-3) Determination of Index for Memory DB Definition The definition information management unit 3423 refers to the index definition information 3460 and specifies the index definition information entry corresponding to the index name acquired as described above (SP105). ). Further, the definition information management unit 3423 changes the memory DB flag of the entry including the index name to be converted into the memory DB among the specified index definition information entries to “YES” (SP106).

(1-6-4) Data Arrangement / Movement to Memory DB The DB access control unit 3427 specifies, in the memory DB management unit 3425, the page of the table 3441 to be converted into the memory DB from the page group on the DB buffer 3430. The specified page is stored in the memory DB 3440, and the page on the DB buffer 3430 is discarded (SP107). For example, if the page here is a table 3441, it indicates at least one table data block constituting the table 3441.

  Further, the DB access control unit 3427 causes the disk DB management unit 3424 to arrange data that has not been moved in step SP107 from the disk DB 3510 to the memory DB 3440 (SP108). That is, when attempting to move a table from the DB buffer 3430 to the memory DB 3440 and the table does not exist in the DB buffer 3430, the DB access control unit 3427 places the table 3441 from the database device 3500 in the memory DB 3440.

  Here, when the table 3511 is moved from the DB buffer 3430 to the memory DB 3440 and the table 3511 does not exist in the DB buffer 3430, the DB access control unit 3427 transfers the table 3511 to the memory DB management unit 3425 from the database device 3500. The table 3511 is arranged in the memory DB 3440.

(1-7) Effects of First Embodiment As described above, in the first embodiment, first, when the processor 3410 of the database management apparatus 3400 receives a definition request in which a specific table is specified, Then, the table definition information 3450 is changed so that the table becomes a target of the memory DB as special processing (corresponding to the table definition change step). Next, when an index is set for the table, the processor 3410 selects the index set for the table based on the index definition information 3460 for the table, and the index becomes a target for making the memory DB. Thus, it is registered in the index definition information 3460 (corresponding to the index determination step). The processor 3410 moves the table from the DB buffer 3430 to the memory DB 3440 based on the table definition information 3450, and arranges the selected index in the memory DB 3440 based on the index definition information 3460 (corresponding to an arrangement step). .

  With the configuration as described above, the database management apparatus 3400 is connected to the database apparatus 3500 via the DB buffer 3430, instead of operating the table 3511 arranged in the database apparatus 3500, the database having a low access speed. A table 3441 arranged in the memory DB 3440 built in the database management device 3400 is operated without going through the device 3500. Then, after making the above definition request, the database management apparatus 3400 does not need to access the database apparatus 3500 when operating the table 3441, so that the table can be operated faster than before.

  Moreover, even when the index 3442 is set in the table 3441, the database management apparatus 3400 operates the table 3441 using the index 3442 because the index 3442 is also arranged in the memory DB 3440. In this case, the table 3441 can be operated at a higher speed than in the past.

  In the first embodiment, when the processor 3410 tries to move the table 3551 from the DB buffer 3430 to the memory DB 3440 as described above, if the table does not exist in the DB buffer 3430, the database device The table 3511 from 3500 is arranged in the memory DB 3440.

  In this case, the table (page) may not exist in the DB buffer 3430 depending on the timing. Even in such a case, the table 3441 can be surely arranged in the memory DB 3440.

  In the first embodiment, the table definition information 3450 includes, for each at least one table 3441, a memory DB flag as specific execution necessity information regarding whether or not it is a target of the memory DB processing. It is out. In addition, in the table definition changing step, when the processor 3410 accepts the definition request, the table 3441 is referred to based on the memory DB conversion flag corresponding to the table 3441 designated by the definition request with reference to the table definition information 3450. Are subject to memory DB conversion processing or are not subject to processing. In this way, it is possible to execute the memory DB processing only for the necessary table 3441.

  Further, in the first embodiment, the index definition information 3460 is converted into a memory DB as another execution necessity information regarding whether or not the combination of the table 3441 and the index 3442 should be the target of the memory DB processing. Contains a flag. Further, in the index determination step, when the processor 3410 accepts the definition request, the processor 3410 refers to the index definition information 3460, and based on the memory DB conversion flag corresponding to the combination of the table 3441 and the index 3442 specified in the definition request. Thus, the combination of the table 3441 and the index 3442 is excluded from or subject to memory DB processing. In this way, it is possible to set whether or not to execute the memory DB processing only for the necessary index 3442.

(2) Second Embodiment Since the second embodiment performs substantially the same configuration and operation as the first embodiment, in the following description, the description of the substantially similar configuration and operation will be given. The description will be omitted with a focus on differences from the first embodiment. In the second embodiment, the database management device 3400 has the same configuration as that of the first embodiment, but the terminal 3100 makes a definition request for releasing the memory DB to the database management device 3400, The difference is that the following processing is performed in response to the definition request.

(2-1) Overview of Database Management Method In the database management apparatus 3400 that has received such a definition request, the processor 3410 executes the following memory DB release processing. This memory DB release processing includes the following arrangement release step. In this arrangement release step, the processor 3410 releases the arrangement of the table already arranged in the memory DB 3440 and also releases the arrangement of the index 3441 already arranged in the memory DB 3440 in the arrangement step described above.

  FIG. 7 shows an example of the procedure of memory DB release processing. This memory DB release processing is executed by the processor 3410 as necessary after the memory DB conversion processing as described above as part of the database management method.

  First, the outline of the memory DB release processing will be described. In this memory DB release processing, when the processor 3410 receives a definition request in which a table 3441 to be released from memory DB is specified, The table definition information 3450 is changed so as to release the database. Further, in this arrangement release step, after the processor 3410 stores the table 3441 arranged in the memory DB 3440 in the DB buffer 3430, the processor 3410 deletes the table 3441 of the memory DB 3440, and the index 3442 arranged in the memory DB 3440 as the database device. Move to 3500.

  More specifically, the database management method in the present embodiment includes the following table definition change step, index release step, and placement release step as the memory DB release processing.

  In the table definition change step, when the processor 3410 receives a definition request in which a table 3441 to be released from the memory DB is specified, the table definition information 3450 is changed so that the table 3441 is a target of the memory DB release process. (SP400). If this definition request is described in SQL, for example, “DEALLOCATE MEMORY TABLE T1” is obtained. The first part “DEALLOCATE MEMORY TABLE” is a declaration statement in which a definition request indicating that the memory DB should be released is described in SQL. The second part “T1” represents a table name to be released from the memory DB, and corresponds to the table 3441.

  In the index release step, when an index is set in the table 3441, the processor 3410 selects an index set for the table 3441 based on the index definition information 3460 for the table 3441, and the index 3442 It is registered in the index definition information 3460 so as to be subject to the memory DB release processing (SP500).

  In the arrangement release step, the processor 3410 stores the table 3441 from the memory DB 3440 into the DB buffer 3430 based on the table definition information 3450, and deletes the table 3441 of the memory DB 3440 (SP600). On the other hand, in this arrangement release step, the processor 3410 generates an index 3442 corresponding to the table 3441 in the disk DB 3510 based on the index definition information 3460 (SP600).

(2-2) Specific example of memory DB release processing FIG. 8 shows an example of a procedure included in the memory DB release processing. This memory DB release processing is executed when the processor 3410 operates each module (such as the definition request receiving unit 3422) of the database management program on the memory 3420. The memory DB release processing is executed while the database management apparatus 3400 is operating, that is, online.

(2-2-1) Acquisition of Memory DB Release Processing Target When performing memory DB release processing, the terminal 3100 issues a definition request for executing memory DB release to the database management device 3400 Then, in the database management apparatus 3400, the definition request accepting unit 3422 receives the definition request (SP400A) and delivers it to the definition information managing unit 3423.

  Here, the definition request for executing the memory DB release (hereinafter referred to as “memory DB release request statement”) is described in SQL, for example, “DEALLOCATE MEMORY TABLE”. The definition information management unit 3423 analyzes the definition request, and acquires the table name that is the target of the memory DB release from the memory DB release request statement (SP401).

(2-2-2) Change of Table Definition Information at Release The definition information management unit 3423 refers to the table definition information 3450 and specifies a table definition information entry corresponding to the acquired table name (SP402). Furthermore, the definition information management unit 3423 changes the memory DB conversion flag of the specified table definition information entry from “YES” to “NO (cancel memory DB conversion)” (SP403).

(2-2-3) Determination of Index to be Deregistered as Memory DB The definition information management unit 3423 refers to the index definition information 3460 and specifies the index definition information entry corresponding to the table name acquired as described above ( SP404). Furthermore, the definition information management unit 3423 changes the memory DB flag of all the entries in the identified index definition information entry to “NULL” (SP405).

(2-2-4) Data Placement / Movement from Memory DB to DB Buffer The DB access control unit 3427 causes the disk DB management unit 3424 to discard the page and index 3442 of the table 3441 on the memory DB 3440 (SP406). . At this time, a frequently accessed page may be selected from pages on the memory DB 3440 of the table 3441 to be released from the memory DB, and the selected page of the table 3441 may be stored in the DB buffer 3430. Thereby, the next data access in the table 3441 can be speeded up using the DB buffer.

(2-2-5) Index Re-creation Step Finally, the processor 3410 generates an index 3442 corresponding to the table 3441 stored in the DB buffer 3430 in the database device 3500 based on the index definition information 3460.

(2-3) Effects of the Second Embodiment According to the second embodiment, the table definition information 3450 and the index definition information 3460 are changed as in the first embodiment as necessary. It is possible to return from the memory DB state to the state where the memory DB state is released.

(3) Other Embodiments The above embodiment is an example for explaining the present invention, and is not intended to limit the present invention only to these embodiments. The present invention can be implemented in various forms without departing from the spirit of the present invention. For example, in the above-described embodiment, the processing of various programs is described sequentially, but this is not particularly concerned. Therefore, as long as there is no contradiction in the processing result, the processing order may be changed or the operation may be performed in parallel.

Claims (9)

A database management method in a database management device for operating the table via a buffer with a database device equipped with a database having at least one table,
When the processor of the database management apparatus receives a definition request in which a specific table is specified, a table definition change step of changing table definition information so that the specific table is a target of special processing;
When an index is set for the specific table, the processor selects an index set for the specific table based on index definition information regarding the specific table, and the selected index is An index determination step for registering in the index definition information so as to be subject to special processing;
An arrangement step in which the processor moves the specific table from the buffer to the special memory based on the table definition information, and places the selected index in the special memory based on the index definition information. A database management method characterized by the above. In the placing step,
When the processor tries to move the specific table from the buffer to the special memory, if the specific table does not exist in the buffer, the specific table is placed in the special memory from the database device. The database management method according to claim 1, wherein: The table definition information is:
For each of the at least one table, including specific execution necessity information regarding whether or not it is a target of the special processing,
In the table definition changing step,
When the processor receives the definition request, the processor refers to the table definition information, and determines the specific table based on the specific execution necessity information corresponding to the specific table specified in the definition request. The database management method according to claim 1, wherein the database management is performed or excluded from special processing. The index definition information is
For each combination of the table and the index, including another execution necessity information regarding whether or not to be the target of the special processing,
In the index determination step,
When the processor receives the definition request, the processor refers to the index definition information, and determines the specific table based on the specific table specified in the definition request and the other execution necessity information corresponding to the index. The database management method according to claim 3, wherein each combination of a table and the index is excluded from or targeted for the special processing. The processor includes a special processing releasing step of releasing the arrangement of the specific table already arranged in the special memory and releasing the arrangement of the index already arranged in the special memory. Item 2. The database management method according to Item 1. In the special processing release step,
When the processor accepts a definition request in which the specific table is specified, a table definition information change step upon release for changing the table definition information so that the special processing is canceled for the specific table;
A deletion step of deleting the specific table and the index arranged in the special memory after the processor stores the specific table arranged in the special memory in the buffer;
The index re-creation step of generating the index corresponding to the specific table stored in the buffer on the database device based on the index definition information. Management method. A database management device for operating the table via a buffer with a database device on which a database having at least one table is mounted,
A definition request accepting unit that accepts a definition request in which a specific table is specified;
When a definition request is accepted by the definition request accepting unit, the table definition information is changed so that the specific table is a target of special processing. On the other hand, if an index is set for the specific table, the specific table A definition information management unit that selects an index set for the specific table based on the index definition information for the table, and registers the index in the index definition information so that the selected index is a target of the special processing; ,
A database access receiving unit that receives an access request to the database device;
A buffer for temporarily storing the table when operating the table with the database device;
A special memory provided separately from the buffer;
A database access controller that moves the specific table from the buffer to the special memory based on the table definition information, and places the selected index in the special memory based on the index definition information. A database management device characterized by the above. A database management program that operates in a database management device that manipulates the table via a buffer with a database device in which a database having at least one table is mounted,
A table definition changing step for changing the table definition information so that the specific table is subject to special processing when receiving a definition request in which the specific table is designated by the processor of the database management device;
When an index is set for the specific table, the processor is caused to select an index set for the specific table based on the index definition information for the specific table, and the selected index is An index determination step for registering in the index definition information to be subject to special processing;
An arrangement step of causing the processor to move the specific table from the buffer to the special memory based on the table definition information, and to place the selected index in the special memory based on the index definition information. A database management program characterized by having A database management system comprising a database device on which a database having at least one table is mounted, and a database management device that operates the table via a buffer between the database devices,
The database management device includes:
A definition request accepting unit that accepts a definition request in which a specific table is specified;
When a definition request is accepted by the definition request accepting unit, the table definition information is changed so that the specific table is a target of special processing. On the other hand, if an index is set for the specific table, the specific table A definition information management unit that selects an index set for the specific table based on the index definition information for the table, and registers the index in the index definition information so that the selected index is a target of the special processing; ,
A database access receiving unit that receives an access request to the database device;
A buffer for temporarily storing the table when operating the table with the database device;
A special memory provided separately from the buffer;
A database access controller that moves the specific table from the buffer to the special memory based on the table definition information, and places the selected index in the special memory based on the index definition information. A database management system characterized by

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