Hitachi, Ltd.

The University of Tokyo

Seisuke Tokuda

Akira Shimizu

Nobuo Kawamura

Shinji Fujiwara

Kazuhiko Mogi

Masaru Kitsuregawa

Kazuo Goda

Kazutomo Ushijima

Michiko Yoshida

Michiko Tanaka

Takaki Nakamura

Norihiro Hara

A database management system (DBMS) generates a query execution plan including information representing one or more database (DB) operations necessary for executing a query and executes the query based on the query execution plan. In the execution of the query, the DBMS dynamically generates a task for executing a DB operation and executes the dynamically generated task. The DBMS executes a task in a plurality of threads executed by a processor core.

Database management system, computer, and database management method

A database management system (DBMS) manages a database existing in a second storage device with an access speed lower than that of a first storage device. In an execution of a query, the DBMS dynamically generates tasks two or more executable tasks in parallel. The DBMS generates task start information which is information representing a content of the execution of the task, manages the task start information, and executes a content represented by the task start information by the task. The task start information includes a data address set existing in the second storage device. The DBMS controls movement of the data address sets between the first storage device and the second storage device based on a management state of the task start information. In addition, the DBMS selects the task start information based on whether or not the data address set exists in the first storage device.

A database management system (DBMS) generates a query execution plan including information indicating one or more database (DB) operations necessary to execute the query. The DBMS dynamically generates a task for executing the DB operation in execution of the query. The DBMS performs a determination processing of simultaneous-task-generation number when newly creating a task. The determination processing of simultaneous-task-generation number is to calculate the number of simultaneous task generation, which is the number of tasks that can be generated simultaneously, based on the number of tasks which can be newly generated, a first memory resource amount which is the amount of memory resources necessary to be allocated per task newly generated, and a second memory resource amount which is the number of memory resources that can be newly allocated. The number of tasks generated dynamically and simultaneously is equal to or smaller than the calculated number of simultaneously generatable tasks.

A database management system (DBMS) generates a query execution plan including information representing one or more database (DB) operations necessary for executing a query, and executes the query in accordance with the query execution plan. In the execution of the query, the DBMS dynamically generates tasks for executing the DB operations and executes the dynamically generated tasks. The query execution plan includes a plurality of query blocks, which are sets of one or more DB operations. When newly generating a task, the DBMS executes determination processing of simultaneous-task-generation number. The determination processing of simultaneous-task-generation number is to calculate, targeting each of the query blocks, the number of simultaneous task generation, which is the number of tasks simultaneously generatable as tasks for executing the query block. The number of the dynamically generated tasks is equal to or smaller than the number of simultaneous task generation.

A computer system, comprising: a computer for outputting a result in response to a request; and a storage system for storing data output based on the request, the computer including: a request reception module for receiving the request; a processing procedure generation module for generating a plurality of processing procedures including an order of access to the data stored in the plurality of storage devices; a data division module for dividing the data; an information obtaining module for obtaining load information indicating a load condition of the storage system; an allotment determination module for determining, based on the obtained load information, allotments for allocating the divided data to be processed by the generated plurality of processing procedures; and a processing execution module for executing, based on the determined allotments, the generated plurality of processing procedures in parallel.

Computer system, data retrieval method and database management computer

It is provided a database processing method including: a first step of receiving a query request instructing to output the requested data as query results in a designated order; a second step of generating a query execution plan including an order of accessing tables for storing the data based on the received query request; a third step of acquiring the data requested based on the query request from the database based on the generated query execution plan; a fourth step of generating intermediate results including the acquired data; a fifth step of sorting the generated intermediate results in the designated order; a sixth step of judging, for each of the intermediate results, whether an order of the sorted intermediate results has been determined; and a seventh step of outputting the intermediate results whose order has been determined as the query results in order from a head thereof.

Database processing method, database processing system and database server

According to this invention, a data arrangement method, the computer connected to a storage system which provides a plurality of logical storage devices comprising a plurality of physical storage devices arranges data in a logical storage volume constructed by integrating the plurality of logical storage devices. The method includes: a step wherein the computer receives an instruction to build the logical storage volume using the plurality of logical storage devices or to rebuild the constructed logical storage volume; a step wherein the computer obtains information about the plurality of physical storage devices constituting each of the plurality of logical storage devices included in the received instruction; and a step wherein the arrangement position of data into the logical storage volume is determined on the basis of the obtained information about the plurality of physical storage devices.

Data arrangement method and data management system for improving performance using a logical storage volume

Provided is a database system in which sorting of query results is sped up. The database system stores storage location information in which storage locations of the pieces of data are recorded in a given order. When there is no second task, which is executed based on data that is fetched in a first task, whether every piece of data requested in a third task, which is executed before the first task, has been fetched is determined. In the case where every piece of data requested in the third task has been fetched, data fetched in the first task is output. In the case where some of the data requested in the third task has not been fetched, data fetched in the first task is kept in a temporary buffer until every piece of data requested in the third task is fetched, and then output.

Database processing system and method

Provided is a database processing system including: a computer for outputting data in response to a received query request; and a storage system including a storage device for storing the data, in which: the storage device stores a plurality of partial indices indicating a storage location of the data; the data stored in the storage device is grouped; and the computer is configured to: receive the query request for the data; acquire one of the plurality of partial indices; specify, based on the query request for the data and the acquired one of the plurality of partial indices, a location at which the requested data is stored; and send a request to acquire the data stored at the specified location to the storage system. Accordingly, in the database processing system, a time period necessary to input and output the data is shortened.

Database processing method and database processing system

At least two devices having different characteristics are provided as one file system, and the file system stores a file in a device according to the file purpose. In file system operation, a device characteristic acquiring unit acquires characteristic information of the respective devices by using a device characteristic database, a device characteristic acquiring interface, and stores the information in the device characteristic holding. In file operation for preparing file management information in file storing process, a file purpose interpreting unit interprets the purpose and attribute of the file and registers a characteristic flag representing the characteristic of the file in the file management information. In file operation for actually writing a file, a storage device decision unit decides a file storage location device on the characteristic flag in the file management information and information of the device characteristic holding unit to perform a device free region securing process.

Storage system

Provided is a database management system obtains storage mapping information which associates addresses in a plurality of physical disk drives within the storage system and addresses in logical disk drives including these physical disk drives, to create queues individually for each of the plurality of physical disk drives. The database management system receives a plurality of read requests which request to read data out of the physical disk drives via the logical disk drives provided by the storage system, sorts the read requests by their destination, and accumulates the read requests in the respective queues associated with the request destination physical disk drives. The database management system reallocates the accumulated read requests into an order that shortens the data read time in each physical disk drive, and then issues the read requests to the storage system.

Method for reading data with storage system, data managing system for storage system and storage system

Provided is a database management system coupled to a storage system comprising a first storage device for storing a database file and a control file, a second storage device for storing a journal corresponding to an update history of the data stored in the first storage device, and a third storage device for storing a log file; generating the journal upon receiving an update instruction; and recording the generated journal to the second storage device in correspondence with a check point. The database management system records the log to the third storage device in correspondence with identification information of the generated check point, restores data stored in the storage system by employing a journal stored in the second storage device before check point, and applies the log stored in the third storage device after the check point to restore a database file.

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Ebina, Japan

Seisuke Tokuda