JP2014194818A - Server and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a server and a program which reduces a time lag of a distribution of data while accumulating information by using a database.SOLUTION: A database driver transmits a database command representing an operation of a database to a database server process for managing the database. The database driver includes: means for determining whether or not the database server process executes a change operation of data stored in a specific area of the database when the database command is analyzed and the database command is transmitted to the database server process; and means for transferring the data based on the change operation to a process different from the database server process when determining the change operation is executed.

Description

  The present invention relates to a technology for linking a database management system and another system.

  Various data have been handled by computer systems. In many cases, data input to a computer system is temporarily stored in a database managed by a database management system, and then transmitted to a device or other system that requires the data. One reason why data is once stored in the database in this way is that the database has a powerful recovery function. Thereby, even if a failure occurs, data can be prevented from being lost. Since the recovery function is provided, data can be reliably delivered via the database.

  In addition to the recovery function, the database also has an access control function, and it is possible to flexibly set data access restrictions for unauthorized persons. Thus, it is possible to provide a specific type of data only to a specific person via the database. In addition, it is possible to perform an auditing operation as to whether there has been an unauthorized access relatively easily (see, for example, Patent Document 1).

US Pat. No. 7,426,512

  On the other hand, information such as stock price and foreign exchange rate is accumulated in securities trading business and foreign exchange business. On the other hand, as represented by algorithm trading, buying and selling orders promptly according to changes in stock price and foreign exchange rate, etc. There is also a need to do. In this case, if information such as a stock price or a foreign exchange rate is distributed via a database, there may be a time lag in information distribution.

  Therefore, an object of one embodiment of the present invention is to further reduce the time lag of data distribution while accumulating information using a database.

  According to an embodiment of the present invention, a database driver that transmits a database command representing an operation to a database to a database server process that manages the database, the database command transmitted to the database server process is analyzed. Means for determining whether or not a change operation of data stored in a specific area of the database is executed by the database server process when the database command is transmitted to the database server process; When it is determined that is executed, a database driver is provided that includes means for transferring data based on the change operation to a process different from the database server process.

  According to an embodiment of the present invention, a computer that transmits a database command representing an operation to a database to a database server process that manages the database, the database command that is transmitted to the database server process is analyzed, and the database command Means for determining whether or not a change operation of data stored in a specific area of the database is executed by the database server process when a database command is transmitted to the database server process; If it is determined, a program is provided for causing data based on the change operation to function as means for transferring the data to a process different from the database server process.

  According to the present invention, it is possible to reduce the time lag of data distribution while accumulating information using a database. Further, synchronization of data update from a database having a specific format or model to a database of another format or model can be ensured.

It is a functional block diagram of database server 100 concerning one embodiment of the present invention. It is a flowchart of the process of the database driver 107 when transmitting the database command which concerns on one Embodiment of this invention. It is a flowchart of the process of the database driver 107 when receiving the result of execution from the database server process 104 concerning one Embodiment of this invention. It is a functional block diagram of a system concerning modification 1 of the present invention.

  Hereinafter, a database server according to an embodiment of the present invention will be described in detail with reference to the drawings. In addition, embodiment shown below is an example of embodiment of this invention, and this invention is not limited to these embodiment.

<Embodiment>
[overall structure]
FIG. 1 shows a functional block diagram of a database server 100 according to an embodiment of the present invention. The database server 100 according to the present embodiment can be provided by operating a computer. The computer has hardware 101, kernel space 102, and user space 103.

  The hardware 101 is a physical entity of a computer. The hardware 101 includes, for example, a CPU, a ROM, a RAM, a secondary storage device, an input / output interface, and the like. The CPU executes instructions constituting the program. The ROM is a read-only memory and stores a program that is executed first when the computer is started. When the computer is activated, a program to be executed first is read from the ROM, and instructions constituting the program are executed by the CPU, so that an operation for booting the computer is started. The RAM is a readable / writable memory, and temporarily stores a program constituted by instructions executed by the CPU, or temporarily stores data necessary for executing the program. The secondary storage device is a device for permanently storing programs and data. The input / output interface is an interface with the outside of the computer for performing input / output of a program, etc., and for performing display and data input accompanying execution of the program.

  The kernel space 102 is a storage space where the operating system operates. The operating system is a kind of program and has a function of abstracting and providing the hardware 101 to processes existing in the user space 103. The operating system also manages processes and resources of the computer.

  One of the functions provided by the operating system operating in the kernel space 102 is an interprocess communication function. The inter-process communication is a function for a plurality of processes to communicate and transmit / receive information. For example, pipes, sockets, shared memory, message queues, etc. are used to implement interprocess communication.

  The user space 103 is an address space in which a process generated using a process management function of an operating system operating in the kernel space 102 exists. The process is a unit for executing the program by setting the CPU mode to the user mode. On the other hand, the kernel space 102 is an address space for executing a program with the CPU mode set to the kernel mode or the like.

  When a process using the hardware 101 occurs or a process using a function of the kernel space 102 needs to be performed, the process issues a system call to the operating system operating in the kernel space 102. Request.

  In FIG. 1, a database server process 104, a client process 105, and a reception process 109 are shown in the user space 103. A database driver 107 is incorporated in the client process 105. Note that processes other than this may exist in the user space 103. A plurality of reception processes 109 may exist.

[Database server process 104]
The database server process 104 is a process for executing a program for realizing a database management system. In other words, it is a process of executing a program for performing operations on the database, specifically storing data in a RAM or a secondary storage device according to a predetermined schema, and executing a program for reading, changing or deleting. A schema is a database structure. For example, in a relational database management system, a schema includes information representing the structure of a table. For example, such information includes information such as the name of the table, the names of the fields constituting the table, the data type, and the presence / absence of an index. Further, such information may include information indicating the status of access authority for a table or the like.

  In the embodiment of the present invention, the database is not limited to a relational database, and various databases such as an XML database, an object-oriented database, a database using a network data model, and a database using a hierarchical data model are used. Can do.

  The database server process 104 receives an operation request for the database from the client process 105 using the inter-process communication function provided by the operating system operating in the kernel space 102, and returns a result of executing the operation. . For example, when a table creation request is received from the client process 105, the database server process 104 executes a table creation process and returns a result of the execution. In addition, when the database server process 104 receives a request for adding data, the database server process 104 executes processing for storing the data in a table, and when a search request is received, searches the data stored in the table for data that satisfies the search condition. When the data change request is received, the data change process stored in the table is executed. When the data deletion request is received, the data deletion process is executed. Then, the database server process 104 returns a result of execution of each process.

  The “execution result” includes information indicating whether or not the process has been successfully executed. For example, when a data deletion request is received, the “result of execution of the data deletion process” indicates whether or not the data deletion process has been successfully executed and, if successful, how many data Contains information indicating whether has been deleted.

  Since the database server process 104 is a process for executing a program for realizing the database management system as described above, the database server process 104 is activated prior to an operation on the database. The database server process 104 performs necessary initialization after startup. The necessary initialization includes a request for realizing necessary inter-process communication for the operating system operating in the kernel space 102. Further, after initialization, the database server process 104 issues a system call for receiving a request for an operation on the database from another process through inter-process communication, and enters a wait state.

  When the database server process 104 receives a database command from the client process 105 and executes the received database command, it issues a system call to record the contents of the database command in hardware such as a secondary storage device. One of the purposes is for logging. For example, the transaction can be rolled back when the database server process 104 performs an operation on the database during the transaction. Another purpose is to reflect in the database operations on the database performed after the point of failure.

[Reception process 109]
The reception process 109 receives data transmitted by the client process 105 by issuing a system call. This data is a part of the client process 105 and is transmitted from the transfer module 108 described later. As a general example of the reception process 109, a process of transmitting received data to a system having a different data storage format or data model from the database managed by the database server process 104 can be cited.

  Examples of such systems with different data storage formats and data models include Hadoop and Key Value Store. Further, such systems with different data storage formats and data models may be operated on the database server 100 or may be operated on a server different from the database server 100. At this time, the reception process 109 may convert the data transmitted from the client process 105 so that the data conforms to the data format of the transmission destination system such as Hadoop or KeyValue Store, and then transmit the data to the transmission destination. Good. When the conversion rule is stored in the storage device of the database server 100 or the like, the reception process 109 may read the rule, perform conversion according to the read rule, and transmit data.

  As a specific example, when the client process 105 receives foreign exchange rate information or stock price information and transmits the received information to the database server process 104, the receiving process 109 Distributes rate information and stock price information to the process of performing transactions using rate information and stock price information. Further, the reception process 109 may be a process itself for performing a transaction using rate information or stock price information.

[Client process 105]
The client process 105 includes a client module 106 and a database driver 107. The client module 106 is a module for executing an operation on the database in the client process 105. When the client module 106 needs to perform an operation on the database, the client module 106 calls a function of the database driver 107 or calls a method. The client process 105 sends a database operation request. This database operation request is transmitted from the database driver 107 to the database server process 104 via interprocess communication. Further, when a result of execution of processing for a database operation request is transmitted from the database server process 104 via inter-process communication, the client process 105 receives it using the database driver 107.

  The database driver 107 is usually provided as a library. That is, the client process 105 program is incorporated when it is compiled or built. The database driver 107 may be provided as a dynamic library. In this case, when the program of the client process 105 is compiled or built, information such as the function and method of the database driver 107 is incorporated, and the substance of the function and method is expanded in the user space or the like when the client process 105 is executed. It may come to be.

  The database driver 107 includes a transfer module 108. The transfer module 108 transmits data based on the database operation request to the reception process 109.

  If the database server process 104 is configured to manage a relational database, the client process 105 makes a system call for performing a database operation request using a database language such as SQL or a function call corresponding to the database language. Issue. As a result, the client process 105 transmits a database operation request based on a communication protocol defined with the database server process 104 via inter-process communication, and receives a result of execution of processing for the request.

  More specifically, the client process 105 issues a system call in the database driver 107 for transmitting a database command representing a request for an operation to the database to the database server process 104. As a result, the inter-process communication module in the kernel space 102 starts processing, and the database server process 104 becomes ready to receive a database command, so that it can run from the wait state. In addition, the client process 105 enters a waiting state in order to receive a reply from the database server process 104.

  When the database server process 104 performs a process of executing a request represented by the database command, it issues a system call for transmitting the result of the execution of the process. As a result, the inter-process communication module in the kernel space 102 starts processing, and the client process 105 becomes ready to receive the result of execution of the processing, so that it can run from the waiting state.

  In the present embodiment, the database driver 107 analyzes a database command which is a request for database operation in addition to the above-described operation. This analysis is a process in which the database driver 107 predicts and determines whether or not an operation for changing data stored in a specific area of the database is performed by executing a database command by the database server process 104. The database driver 107 inquires of the database server process 104 whether or not an operation for changing data stored in a specific area of the database is performed by executing the database command, and performs this determination based on the result. Also good. For example, such a query may be performed by executing a SQL statement that does not perform data manipulation by the database server process 104, such as a dynamic SQL PREPARE statement.

  If the database driver 107 determines that an operation for changing data stored in a specific area of the database has been performed, the database driver 107 obtains the changed data based on the database command and passes the changed data to the transfer module 108. . The transfer module 108 transfers the changed data passed from the database driver 107 to the reception process 109.

  Note that the database driver 107 may determine that an operation for changing data stored in a specific area of the database has been performed, or may satisfy a predetermined condition. For example, if the database is a relational database, a change operation is performed on a specific table and a specific column of specific row data is set as a case where this “predetermined condition” is satisfied. For example, a change operation may be performed. Specifically, the former includes the addition of row data to a specific table and the deletion of row data in a specific table, and the latter includes the row data stored in a specific table. For example, some changes.

  Further, this “predetermined condition” may be set by the reception process 109 or the database server process 104.

[Data transmission example]
Hereinafter, a case where the INSERT statement and the UPDATE statement are executed in the database server 100 will be described. For example, when data (V1, V2, V3) is added to a table R having C1, C2, and C3 as columns, the client process 105
INSERT INTOR (C1, C2, C3) VALUES (V1, V2, V3);
The SQL statement or the function corresponding to it is executed. In this case, a database command representing this SQL statement is transmitted from the client module 106 and transmitted to the database server process 104 via the database driver 107 and interprocess communication.

  When the database server process 104 receives the database command representing the INSERT statement, it adds data (V1, V2, V3) to the table R and adds data (V1, V2, V3) to the table R. Issue a system call to write the changes.

  On the other hand, when “data stored in a specific area of the database” is set as data added to the table R, the database driver 107 indicates that the database command transmitted from the client module 106 is in response to the table R. It is determined that the data addition is indicated, and data (V1, V2, V3) is transferred to the transfer module 108. The transfer module 108 transfers the received data (V1, V2, V3) to the reception process 109. At this time, the value of the primary key may be included so that the data added by the INSERT statement can be specified.

  Note that the database driver 107 may pass a part of V1, V2, and V3 to the transfer module 108 instead of passing the data (V1, V2, V3) to the transfer module 108. In this case, a part of V1, V2 and V3 is transferred to the reception process 109. Further, the database driver 107 may add additional data such as time data such as the time of determination to the data to be transmitted as described above.

Further, if the column C1 of the table R is a primary key column, the database driver 107 can also store V1, which is the value of the primary key column. By doing so, the most recently added data of the table R is specified by the value of C1 being V1. At this time, the client process 105
UPDATE R SET C2 = V4, C3 = V5 WHERE C1 = V1;
Is executed, the database server process 104 executes the corresponding SQL command and writes the values (V1, V4, V5) representing the data after the data change. Issue a system call for

  On the other hand, the database driver 107 determines that it represents a change to the row whose column value is V1 in the data of the table R, and obtains the changed data (V1, V4, V5) and (V1, V4, V5) is transferred to the transfer module 108. The transfer module 108 transfers the received data (V1, V4, V5) to the reception process 109. At this time, the value of the primary key may be included so that the data added by the INSERT statement can be specified.

  The database driver 107 may pass part or all of V4 and V5 to the transfer module 108 instead of passing the data (V1, V4, V5) to the transfer module 108. In this case, part or all of V4 and V5 is transferred to the reception process 109. Further, the database driver 107 may add additional data such as time data such as the time of determination to the data to be transmitted as described above.

[Operation of Database Driver 107]
Next, the processing of the database driver 107 will be described separately for a case where a database command is transmitted to the database server process 104 and a case where an execution result is received from the database server process 104. First, processing of the database driver 107 when a database command is transmitted to the database server process 104 will be described.

  FIG. 2 is a flowchart of processing of the database driver 107 when transmitting a database command according to an embodiment of the present invention. First, the database driver 107 waits for a database command to be transmitted from the client module 106 (step S110; No). When a database command is transmitted from the client module 106 (step S110; Yes), the database driver 107 analyzes the database command and determines whether it represents a data operation on a specific table (step S120). Here, as an example of determining whether or not “data stored in a specific area of the database” is described as determining whether or not “a data operation is performed on a specific table”.

  If the analyzed database command represents a data operation on a specific table (step S120; Yes), the database driver 107 obtains data after the data operation (step S130). The transfer module 108 receives the data obtained by the database driver 107 and transfers the received data to the reception process 109 (step S140).

  Subsequently, after the process of step S140 or when the database command analyzed in step S120 does not represent a data operation for a specific table (step S120; No), the database driver 107 proceeds to the database server process 105. A database command is transmitted (step S150). If there is no instruction to end the process shown in FIG. 2 (step S160; No), the database driver 107 returns to step S110 to continue the process, and if there is an instruction to end the process shown in FIG. In S160; Yes, the process is terminated.

  Next, processing of the database driver 107 when receiving an execution result from the database server process 104 will be described.

  FIG. 3 is a flowchart of the processing of the database driver 107 when receiving the execution result from the database server process 104 according to an embodiment of the present invention. First, the database driver 107 waits for a database command process execution result to be transmitted from the database server process 104 (step S210; No). When the execution result is transmitted (step S210; Yes), the database driver 107 transmits the execution result of the database command processing to the client module 106 (step S220). If there is no instruction to end the process shown in FIG. 3 (step S230; No), the database driver 107 returns to step S210 and continues the process, and if there is an instruction to end the process shown in FIG. In S230; Yes, the process is terminated.

  As described above, in the database server 100 according to the present embodiment, the database driver 107 in the client process 105 analyzes the database command transmitted from the client module 106, and the data stored in a specific area of the database is changed. Is determined, the changed data is obtained, the changed data is transferred to the transfer module 109, and can be received by the reception process 109. As a result, the reception process 109 can obtain data without waiting for the database server process 104 to store the data in the database, and can reduce the time lag of data distribution. It is also possible to convert the distributed data by the reception process 109 or the database driver 107.

<Modification>
As mentioned above, although embodiment and the Example of this invention were described, this invention can be implemented in various aspects as follows.

[Modification 1]
In the embodiment described above, the database server 100 is realized by one computer, but may be realized by a plurality of computers. For example, it may be realized by two computers as shown in FIG.

  FIG. 4 is a functional block diagram of a system according to the first modification of the present invention. In the example shown in FIG. 4, a first computer 700A having hardware 701, kernel space 702, and user space 703, and a second computer 700B having hardware 711, kernel space 712, and user space 713 are used. The present invention can be implemented. In this case, the database server process 704 may operate in the user space 703 of the first computer 700A, and the client process 705 and the reception process 709 may operate in the user space 713 of the second computer 700B. The function of each process in the modification 1 is the same as the function of each process in the embodiment.

  The database command transmitted from the client process 705 to the database server process 704 is transmitted via the kernel space 712, hardware 711, communication network 800, hardware 701 of the first computer 700A, and kernel space 702 of the second computer 700B. Sent from the client process 705 to the database server process 704.

  As a result of executing the processing of the database command transmitted from the database server process 704 to the client process 705, the result of executing the processing of the database command is the kernel space 702, hardware 701, communication network 800, second network of the first computer 700A. The data is transmitted from the database server process 704 to the client process 705 via the hardware 711 and the kernel space 712 of the computer 700B.

DESCRIPTION OF SYMBOLS 100 ... Database server, 101, 701, 711 ... Hardware, 102, 702, 712 ... Kernel space, 103, 703, 713 ... User space, 104, 704 ... Database server, 105, 705 ... Client process, 106, 706 ... Client module, 107, 707 ... Database driver, 108, 708 ... Transfer module, 109, 709 ... Reception process, 700A ... First computer, 700B ... Second computer, 800 ... Communication network

Claims (2)

A server that sends a database command representing an operation to a database to a database server process that manages the database,
When the database command to be transmitted to the database server process is analyzed, and the database command is transmitted to the database server process, an operation for changing data stored in a specific area of the database is executed by the database server process Means for determining whether or not
Means for transferring data based on the change operation to a process different from the database server process when it is determined that the change operation is executed;
When determining whether the change operation is performed, determine whether the database command is due to the addition of data to a particular table of the database;
The data based on the change operation is all or part of the data added to the specific table,
Storing the value of the primary key added to the specific table;
When determining whether or not the change operation is executed, it is determined whether or not a change operation of data of the specific table specified by the stored primary key is executed,
The data based on the change operation is a server that is a value after the change operation is executed. A computer for sending a database command representing an operation to a database to a database server process for managing the database;
When the database command to be transmitted to the database server process is analyzed, and the database command is transmitted to the database server process, an operation for changing data stored in a specific area of the database is executed by the database server process Means for determining whether or not
When it is determined that the change operation is executed, the data based on the change operation is functioned as means for transferring to a process different from the database server process,
A program for determining whether or not the database command is due to the addition of data to a specific table of the database when determining whether or not the change operation is executed;
The data based on the change operation is all or part of the data added to the specific table,
Further to the computer,
Storing the value of the primary key added to the specific table;
When determining whether or not the change operation is executed, a program for determining whether or not the change operation of the data of the specific table specified by the stored primary key is executed,
The data based on the change operation is a program that is a value after the change operation is executed.

Images