Abstract: An index tree search method, by a computer, for searching an index tree included in a database provided by the computer which includes processors executing a plurality of threads and a memory, the index tree search method comprising: a first step of allocating, by the computer, search ranges in the index tree to the plurality of threads; a second step of receiving, by the computer, a search key; a third step of selecting, by the computer, a thread corresponding to the received search key; and a fourth step of searching, by the computer, the index tree with the selected thread using the received search key.

Abstract: A blockwise-erase nonvolatile storage device for storing a database includes extended logical-to-physical conversion information that associates, for each of a plurality of logical addresses, a timestamp, a physical address, and a reference counter with each other. Each reference counter indicates the number of referring sources to refer to data associated with both the logical address and the timestamp that are associated with the reference counter. On the basis of the conversion information, it is determined whether a target logical address has associated therewith a timestamp older than the latest timestamp and whether the reference counter associated with both the target logical address and the older timestamp indicates that there is no referring source. If so, then the blockwise-erase nonvolatile storage device manages, as an erasable physical area (invalid physical area), the physical area at the physical address associated with both the target logical address and the older timestamp.

Abstract: A database management system generates a log each transaction during execution of a plurality of transactions and stores the generated logs in log storage areas. The database management system records sequence numbers of logs at least in the generated logs of transactions belonging to a set of transactions of which results are different depending on a transaction execution order.

Abstract: Provided is a log management method in which, with a computer system provided with a processor, a memory, and a storage device, the processor executes a prescribed process and stores in the storage device a log which includes a description of the process, said method comprising a first step of the processor generating the log which includes the description of the prescribed process, a second step of the processor writing the log to a log file of the storage device, and a third step of the processor determining the end of the log region which stores the log and writing same to the log file of the storage device.

Abstract: A blockwise-erase nonvolatile storage device for storing a database includes extended logical-to-physical conversion information that associates, for each of a plurality of logical addresses, a timestamp, a physical address, and a reference counter with each other. Each reference counter indicates the number of referring sources to refer to data associated with both the logical address and the timestamp that are associated with the reference counter. On the basis of the conversion information, it is determined whether a target logical address has associated therewith a timestamp older than the latest timestamp and whether the reference counter associated with both the target logical address and the older timestamp indicates that there is no referring source. If so, then the blockwise-erase nonvolatile storage device manages, as an erasable physical area (invalid physical area), the physical area at the physical address associated with both the target logical address and the older timestamp.

Abstract: Provided is a log management method in which, with a computer system provided with a processor, a memory, and a storage device, the processor executes a prescribed process and stores in the storage device a log which includes a description of the process, said method comprising a first step of the processor generating the log which includes the description of the prescribed process, a second step of the processor writing the log to a log file of the storage device, and a third step of the processor determining the end of the log region which stores the log and writing same to the log file of the storage device.

Abstract: An index tree search method, by a computer, for searching an index tree included in a database provided by the computer which includes processors executing a plurality of threads and a memory, the index tree search method comprising: a first step of allocating, by the computer, search ranges in the index tree to the plurality of threads; a second step of receiving, by the computer, a search key; a third step of selecting, by the computer, a thread corresponding to the received search key; and a fourth step of searching, by the computer, the index tree with the selected thread using the received search key.

Abstract: 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.

Abstract: 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.

Abstract: A database management system generates a log each transaction during execution of a plurality of transactions and stores the generated logs in log storage areas. The database management system records sequence numbers of logs at least in the generated logs of transactions belonging to a set of transactions of which results are different depending on a transaction execution order.

Abstract: 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.

Abstract: The present invention is a method of managing a database, which manages a graph database and a relational database on a computer provided with a processor and memory, wherein the computer acquires frequency of reference for each type of node of a graph database, extracts types of nodes for which the reference frequency is greater than or equal to a threshold, converts the extracted nodes to a table structure, and then retains the same as an intermediate table, and upon receiving an inquiry by the relational database, references the intermediate table.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A shared-nothing database management system employs a method of adding and removing a database server without significantly affecting the processing performance for accessing a table from a user or an application. A scheduler module creates a schedule which separately handles the addition of a CPU resource and the addition of a storage I/O resource, and a server is added in accordance with the created schedule. A common disk is used to remove a disk at an arbitrary timing. Further, a data region is previously subdivided on the common disk to eliminate a movement of data associated with the addition of a server.

Abstract: A document search apparatus capable of an index-type search and a scan-type search performs a search in a combination of the two search types while compensating for the disadvantages of the two search types with each other. A search query for index-type search and a search query for scan-type search are constructed based on a search query consisting of a logical formula of keywords. Then, a character 2-gram for performing an index search is set to shorten the whole search time, and the index-type search is performed. Finally, a scan-type search is performed on this search result of the index-type search.

Abstract: A database management system has a plurality of database servers and data can be transferred between them by partitioning a data area into small areas and altering allocation of the small areas to the database servers. After altering the configuration, there occurs degradation in processing speed that accompanies re-creation of the index. If this problem is solved by using conventional techniques, noticeable degradation in processing speed will occur to a specific query at the time of a steady state operation. Accordingly, an index created for each of the small areas and an index to all of the small areas are allocated to the database server and used in combination.