JPH07104806B2 - Database processing system - Google Patents

Description

Detailed Description of the Invention TECHNICAL FIELD OF THE INVENTION

The present invention relates to a database processing system, and in particular, a database (DB) when a failure occurs.
For the database access unit (DBU) used as a processing unit that restores the contents of the DBU to the state before the start of processing, the initialization processing such as buffer acquisition and the end processing such as buffer return accompanying the generation and termination of Start declaration (ATT
ACH instruction) and end declaration (DETACH instruction) are not executed in synchronism with each other, but are executed in synchronization with the occurrence and end of transactions to shorten the occupied period of buffers in the memory and improve memory utilization efficiency. It relates to a dynamic generation method of a database access unit that improves the performance.

[Technical background]

In the database processing system, the access process to the database is performed with the database access unit DBU as a basic unit. A DBU (database access unit) is an application / business program (APL) that accesses a database (DB) as shown in Fig. 4, and encounters a failure during a specified processing period that includes access to the DB. In this case, it means a logical processing unit that causes the system (DBMS) to restore the contents of the DB to the state before the processing period, and requests a guarantee for the validity of the DB. Here, the APL declares the start of access to the database by the ATTACH command at the beginning of the processing range (for example, the shaded area in Fig. 4) that you want to guarantee the validity of the DB, and at the end point.
Declare the end of access to the database with the DETACH command. Regarding the APL DB access processing within the DBU enclosed by the start declaration and end declaration, the system (DBMS) guarantees the validity of the DB against failures and the like that occurred during this time. For example this
When an error is encountered in the DBU, the DBMS guarantees to the APL that the contents of the DB are in the state immediately before the start declaration. The contents are guaranteed to be in the state immediately after the termination declaration was issued. At the time of starting the DBU, the initial setting of the mechanism for acquiring the DB pre- and post-update information for guaranteeing the processing (that is, guaranteeing the DB) is performed. In general, in an online database system, since quick response performance is important, when the DBU start declaration is made,
Preparations are made for loading directories (index tables) and various indexes, securing access buffer areas, etc., so that the overhead for each transaction does not increase when a transaction is subsequently input. FIG. 1 shows an outline of such a conventional processing system. In the figure, 1 is a database processing system, 2 is a database management system DBM, and 2a is ATTACH.
Processing program, 2b DETACH processing program, 3 internal memory, 4 file management system, 5 database, 6 to 8 application programs of users A to C, 9 and 10 buffers secured on DASD, Indicates. For user A, a job (application program 6) that does not use the database is processed, and the buffer is not secured. User B
With respect to the above, the ATTACH instruction is issued, the DBU for accessing the database is generated, and the buffer 9 is secured by the ATTACH processing program 2a. User C
For, by finishing the database processing,
This shows a state in which the DETACH instruction has been issued, the DBU has ended, and the DETACH processing program 2b has returned the buffer 10. Similarly, in the internal memory 3, the generated DBU
The necessary area is secured and returned every time. Generally, in large real-time systems such as banking, the number of applications can be 100-200 and transactions can reach 1 million transactions per hour when concentrated. On the other hand, some applications are used very infrequently.
Some occur only a few times a day or at a limited time during the month. The size of the buffer depends on the application, but normally, several pages to several tens of pages are secured with one page having 256 KB. As in the real-time system of the banking department mentioned above, where transactions occur continuously and with high density and a short response time of a few seconds or less is required, in the morning the ATTA is started at the same time as the system starts operating.
The CH command is issued to generate a DBU, and the buffer is secured until the end of the work.
However, in a TSS system where processing is performed in an interactive manner, the actual efficiency of use of the buffer secured by DBU generation is often very poor, and such interactive processing does not require high-speed response. Often. Furthermore, in a function-distributed multi-computer system, a computer that shares a function with a low transaction distribution ratio reserves a buffer at the same time as another computer that shares a function with a high transaction distribution ratio when generating a DBU. There was a problem of low efficiency.

[Object and Structure of the Invention]

In the static DBU generation method in the conventional system described above, D
Immediately after a BU start declaration is made, initialization processing such as acquiring a buffer in the memory is performed, and after the DBU end declaration is made, termination processing such as returning the buffer is performed.
Therefore, from the time the DBU is declared to the end to the end
There is a problem that the area of the memory remains occupied by the buffer and the utilization efficiency of the memory decreases. An object of the present invention is to improve memory efficiency when generating a DBU. In the conventional system, regardless of the occurrence and end of a transaction, for example, the DBU start declaration of all APLs is made in the morning and initialization processing is performed, and at the end of the service (eg, in the evening).
In the present invention, the initialization process and the end process are separated from the DBU start declaration and the end declaration, and the transaction is generated and ended after the DBU start declaration. A dynamic DBU generation method that is executed in synchronization is adopted. That is, it is possible to specify whether static DBU generation is dynamic DBU generation in the parameter of "DBU start declaration (ATTACH)". With dynamic DBU generation specification, initialization processing such as buffer acquisition is not performed at the time of start declaration, "Initialization processing + execution of DB access instruction" when a transaction (a series of processing units including a DB access instruction) is accepted
On the other hand, the end processing is executed at the end of the transaction without waiting for the end declaration of the DBU, and the function of enabling the release of the buffer is provided. According to the present invention, an area such as a buffer can be acquired for a required period, and the memory can be effectively used. As a configuration for this purpose, the present invention uses a period defined by a start declaration and an end declaration of a database access issued by an application as a logical processing unit to perform initialization processing such as securing a buffer area related to database access and occurrence of a failure. Database access unit that performs database recovery processing in case of
In a database processing system that manages a database access process using a DBU, immediately after receiving the above-mentioned database access start declaration, either statically generate a DBU for performing the above initialization process or receive the start declaration. Even if a transaction is received during system operation after the start declaration is made without executing the initialization processing, the initialization processing is executed Dynamically manages for each application whether DBU is dynamically generated DBU generation instruction means, and the dynamic DBU for the application that issued the start declaration when the start declaration of the database access is received.
A start declaration recording unit that suppresses the execution of the initialization process and records that the start declaration is issued when the generation instructing unit instructs the DBU to be dynamically generated; and the dynamic DBU generation instructing unit If static creation of DBU is instructed in, the initialization processing is executed by receiving the start declaration of the database access, and if dynamic creation of DBU is instructed, a transaction from the application is started. When a start declaration from the application is recorded in the start declaration recording means at the time of performing the DBU start means for executing the initialization processing, and the dynamic DBU generation instruction means is instructed to statically generate the DBU. If the database access end declaration is received, DBU end processing such as buffer return is executed,
In addition, if DBU dynamic generation is instructed, the DB will be deleted when the transaction from the application is terminated.
DBU terminating means for executing U termination processing.

Examples of the invention

FIG. 2 shows an example in which the present invention is applied to a function distributed type multiple computer system. In the figure, 11 to 14 indicate computer CPU ₁ , CPU ₂ , CPU ₃ , and CPU ₄ , respectively, which form a distributed network. 15 is a database file I, 16 is a database file I
Reference numerals I and 17 to 19 denote signal line paths. CPU ₁ and CPU ₃ are computer for message processing, and CPU ₂ and
CPU ₄ is a computer for business processing. Also, CPU ₁ and CPU ₂ , CP
U ₃ and CPU ₄ are located in the same area. CPU
₄ has the function of processing all transactions input to CPU ₃ using database II, but CP
U ₂ and database I have a processing function to balance the load amount for transactions with some characteristics of transactions input to CPU ₁ , for example, those for special data. It has not been. They are CP
It relies on U ₄ and Database II for its processing.
Therefore, CPU ₁ analyzes the transaction characteristics and
For some transactions, control to direct the processing to CPU ₄ . Traditionally, when DBUs were generated for applications that process these transactions, CPU ₂ and CPU ₂
Buffers were allocated to both ₄ at the same time. However, the ratio of transactions distributed from CPU ₁ to CPU ₄ is smaller than that of transactions distributed to CPU ₂ , so normally the buffer reserved for this for CPU ₄ is used more frequently. Lowers memory efficiency. In the embodiment of the present invention, in order to solve this point, each path is provided with one attribute that is conditioned by the application. For example, in one application, when the ATTACH instruction is issued, the path from CPU ₁ to CPU ₂ is given. DBU generation is allowed unconditionally for 17, while for the path 19 going from CPU ₁ to CPU ₄ , the ATTACH instruction transmission is temporarily suspended and a transaction using this path 19 occurs. For the first time, the ATTACH instruction that was previously held is transmitted to the CPU ₄ together with the GET instruction. Therefore, the CPU ₄ first generates the DBU by the ATTACH instruction transmitted with the occurrence of the transaction, executes the buffer reservation, and immediately executes the GET instruction to read the record and execute the transaction processing. To do. Further, the DBU of the CPU ₄ is terminated upon completion of the transaction. In this way, the DBU is generated and terminated for each transaction distributed by the application 19 to the CPU ₄ by a certain application, so that the memory efficiency is significantly improved. Of course, other applications can be set to generate static DBU between CPU ₁ and CPU ₄ . FIG. 3 is a specific explanatory diagram of a control function for static DBU generation and dynamic DBU generation between the CPU ₁ and the CPU ₄ in the embodiment of FIG. In the figure, 11 is CPU ₁ and 14 is CP
U ₄ and 20 are user application processing units, 21 is a database management system DBM, 22 is an ATTACH processing program, 2
Reference numeral 3 is a command stack program, 24 is a GET processing program, 22a, 24a and 24b are determination processing for identifying whether DBU dynamic generation / static generation is set, and 25 is a communication program. In addition, a signal line shown by a solid line is a flow of transmission data, and a signal line shown by a chain line is a flow of received data.
′, Is the process flow when DBU static generation, ′,
, ', Indicate the flow of processing when DBU is dynamically created. In this embodiment, the setting of DBU dynamic generation / static generation is performed by a user's instruction or control information incorporated in an application in advance. Identification information is added to the command or control signal sent from the application processing unit 20 to the DBM21 in order to instruct the DBM21 whether to dynamically generate the DBU or to statically generate it.
In 1, the determination processing 22a, 24a, 24b is used to identify the DBU dynamic generation / static generation and separate the control. In addition, dynamic DBU generation for each application /
Register one of the static generation in the table in advance and manage it,
When the DBM 21 is activated by the application processing unit 20, it is possible to adopt a suitable method according to the purpose, such as a method of determining by referring to the table. When dynamic generation of DBU is not required, that is, when static generation of DBU is specified, when the user issues an ATTACH command, the ATTACH processing program 22
In the determination processing 22a, it is determined that the DBU is statically generated, and the CPU ₄
Is instructed to execute ATTACH processing. The CPU ₄ carries out the ATTACH process, and makes it possible to accept access to the DB thereafter. Then, the execution result is answered by the route of '. Next, when a GET instruction is issued due to the occurrence of a transaction, as shown by the route of, in the determination processing 24a of the GET processing program 24, it is determined that static generation of DBU is instructed, and the CPU ₄ is instructed to execute the GET processing. Execution is commanded. CPU ₄
Is already in a state where access to the DB can be started, so GET
Execute the process. The execution result of the GET process is answered by the route '. Since the subsequent transaction end is determined to be statically generated in the determination process 24b in the route of, the DETACH process is not commanded. Finally, when the DETACH instruction is issued, at the root of, CPU ₄
In, the DETACH process is executed unconditionally, the end of access to the database is declared, and access to the DB is not accepted until the ATTACH process is executed thereafter. When DBA dynamic generation is specified and the ATTACH command is issued from the user (APL), it is determined that dynamic generation is instructed in the determination processing 22a of the ATTACH processing program 22 at the route of Control is transferred to the stack program 23. The ATTACH instruction is temporarily stored in the command stack by the program 23 and is answered with '. However, unlike the case of the DBU static generation in FIG. 3, nothing is instructed to the CPU ₄ . Next, user with DBU dynamic generation specified (APL)
After the ATTACH command is issued and processed by the, a GET command is issued due to the occurrence of a transaction, it is determined that dynamic generation is instructed in the determination processing 24a of the GET processing program 24 by the route. If the dynamic generation is instructed here, the command stack is then referred to, the ATTACH instruction is taken out, and the CPU ₄ is instructed to execute the ATTACH and GET processing together with the GET instruction. CPU ₄ is A
The TTACH process is executed, the buffer is secured, and the DB is accessible, and then the GET process is performed to access the DB. The execution result is answered with '. At the end of transaction processing, GE
The determination processing 24b of the T processing program is activated. If it is determined that the dynamic generation is instructed here, the CPU ₄
TACH processing is commanded and the end of access to the DB is declared,
Performs processing such as releasing the buffer area reserved for DB access. As described above, based on the condition setting from the application side, it is determined whether the DBU is dynamically generated or statically generated, and when the dynamic generation is instructed, the transaction is synchronized with the generation and end of the transaction. DBU is generated and terminated. In general, service characteristics such as the tolerance for the response time from when the user or application issues an access request to the DB until the response is returned from the system are matters that the system does not understand, so the response time is long. However, it is appropriate for the user to set whether to generate DBU dynamically to improve memory efficiency or to statically generate DBU to reduce memory time but reduce response time. It is also possible to set according to the conditions on the side, for example, the management table described above or the contents specified by the manager, and it is included in the scope of the present invention. Although the above-described embodiment relates to the distributed multiple computer system, the basic configuration and function in the database management system DBM in this embodiment can be commonly applied to other uses such as a time-sharing system. It is a thing.

According to the present invention, a user can flexibly design a memory according to an acceptable level of service characteristics on the user side, the efficiency of the memory can be improved, and the distributed system can be achieved. In the case of applying to the above, since the utilization of the memory is enhanced, the number of times of communication can be expected to be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a conventional database processing system, FIG. 2 is a block diagram of a distributed multi-computer system, FIG. 3 is a functional block diagram of an embodiment system, and FIG. 4 is an explanatory diagram of DBU. . In the figure, 11 and 14 are CPUs, 20 is an application processing unit, 21 is a database management system, 22 is an ATTACH processing program, 24 is a GET processing program, 22a, 24a and 24b are determination processing, and 25 is a communication program.

Front page continuation (72) Inventor Koichi Sato 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (1)

[Claims] 1. Initialization processing such as securing a buffer area related to database access and database restoration when a failure occurs, with a period defined by a start declaration and an end declaration of database access issued by an application as a logical processing unit. In a database processing system that manages database access processing using a database access unit DBU that executes processing, etc., a DBU that executes the initialization processing immediately after receiving the start declaration of the database access is generated statically, Even if the start declaration is received, the initialization processing is not performed, and when the transaction is received during the system operation after the start declaration is made, the application that determines whether to dynamically generate the DBU that performs the initialization processing is received. Dynamic DBU generation instruction means for managing each Said dynamic DBU for the application that issued the start declaration upon reception of the base access start declaration
A start declaration recording unit that suppresses the execution of the initialization process and records that the start declaration is issued when the generation instructing unit instructs the DBU to be dynamically generated; and the dynamic DBU generation instructing unit If static creation of DBU is instructed in, the initialization processing is executed by receiving the start declaration of the database access, and if dynamic creation of DBU is instructed, a transaction from the application is started. When a start declaration from the application is recorded in the start declaration recording means at the time of performing the DBU start means for executing the initialization processing, and the dynamic DBU generation instruction means is instructed to statically generate the DBU. If the database access end declaration is received, DBU end processing such as buffer return is executed,
In addition, if DBU dynamic generation is instructed, the DB will be deleted when the transaction from the application is terminated.
DBU terminating means for executing U termination processing, and a database processing system.