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 method for producing alumina comprising the steps of mixing an aqueous medium in an amount of 20 parts by weight or more and 300 parts by weight or less with 100 parts by weight of a first dry powdery aluminum hydroxide prepared by an aluminum alkoxide method to give a wet powdery aluminum hydroxide; drying the wet powdery aluminum hydroxide by an agitation drying system to give a second dry powdery aluminum hydroxide; and calcining the second dry powdery aluminum hydroxide to give alumina having a high bulk density.

Abstract: ?-Alumina powder is provided having a purity of 99.99% by weight or more, a specific surface area of from 0.1 to 2.0 m2/g, a relative density of from 80 to 95%, a closed porosity of 4% or less, and a loosed bulk density of 2.4 g/cm3 or more, which is measured by a method for measuring physical properties of alumina powder according to JIS R9301-2-3 (1999).

Abstract: 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.

Abstract: There is provided a process for the preparation of a alumina precursor powder from aluminum hydroxide powder obtained by hydrolysis of aluminum alkoxide which precursor enables to provide alumina powder with a high volumetric efficiency. Such process comprises mixing aluminum hydroxide powder obtained by hydrolysis of an aluminum alkoxide with the following aqueous medium so as to obtain an aluminum hydroxide mixed slurry and then drying the aluminum hydroxide mixed slurry: aqueous medium: water or a medium mixture of water and a water-soluble alcohol wherein a water content in said medium mixture is not less than 15 parts by weight to 100 parts by weight of the medium mixture.

Abstract: A method for rapidly executing a series of remote procedure calls between a client and a server, comprising an RPC optimizer (101) that inputs an IDL source code (103) and client source codes (102, 102?, . . . ) so as to define as a new remote procedure a group of remote procedures to be performed by the client in an additional server source code (107). In turn, the RPC optimizer outputs a new IDL source code (106) to which an interface of the remote procedure is added, and new client source codes (105, 105?, . . . ) modified so as to use the remote procedure. This reduces communications involving a plurality of remote procedures to a single communication pass, thereby implementing high-speed communication between the client and the server.

Abstract: ?-Alumina powder having a purity of at least 99.99% by weight, a specific surface area of from 0.1 to 2.0 m2/g, a relative density of from 55 to 90%, and a closed porosity of 4% or less, wherein in a weight-based particle size distribution obtained by the dry sieving test according to JIS K0069 (1992), an amount of particles having a particle size of less than 75 ?m is 5% by weight or less; an amount of particles having a particle size exceeding 2.8 mm is 15% by weight or less; and at least one frequency maximum peak appears in a particle size range of 100 ?m or more and to less than 850 ?m. This ?-alumina powder can be charged in a crucible at a high bulk density, from which sapphire having a few voids can be produced without causing the oxidation of a crucible in a heat melting step.

Abstract: Provided is a backup method including a step (S1) of reading a log which is a data update difference, and identifying a data storage area (page) of backup data, a step (S2) of determining high/low reusability of the identified data storage area, a step (S3) of storing a log corresponding to a data storage area determined to be low in reusability in a log storage area preset on a memory, and a step (S4) of applying a log corresponding to a data storage area determined to be high in reusability to the identified data storage area in a cache area set on the memory, and updating the data storage area. Thus, by further reducing the number of I/O times in an external storage system of a standby system which backs up data by log transfer, it is possible to reduce introduction costs of a backup system and its normal-time operation's costs at normal times.

Abstract: A method of managing data by a storage system having first and second volumes according to a command from a server computer, including receiving a data access command from the server computer; specifying a data area that is designated in the data access command and reading data in the data area from the first volume; judging whether the data access command contains a data evacuating instruction; judging whether the data in the data area has been evacuated to the second volume when the data read command contains the data evacuating instruction; evacuating the data in the data area to the second volume when the data in the data area has not been evacuated to the second volume; and sending the data in the data area to the server computer. The invention reduces loads on the storage system when a differential snapshot is used.

Abstract: To generate backup data based on a log while a power consumption of a standby system is reduced, provided is a method for data backup in which a first computer system transmits a data update record, a second storage system of a second computer system receives and then stores the data update record, and a second computer of the second computer system generates a copy of data contained in the first computer system based on the stored data update record, the method for data backup, including: monitoring the data update record transmitted by the first computer system, and stopping, when a predetermined first condition is satisfied, the second computer; and starting, when a predetermined second condition is satisfied, the second computer, thereby generating the copy of the data contained in the first computer system based on the stored data update record.

Abstract: A method for duplicating transactions in a disaster recover system is disclosed. In this method, transactions and queries input to a primary database system are copied to a secondary database system and both database systems execute the queries and save the results permanently to each database, thereby maintaining duplicated data. When executing a query on the primary database system, if the query is a commit, the primary system simultaneously copies uncopied queries placed in a queue to the secondary database system and then executes the query. By using this processing procedure, the invention realizes a disaster recovery system which carries out copying transactions from one site to another site without losing the transactions, while reducing the influence of copy operation on the transaction processing performance.

Abstract: The invention relates to a method of virtualizing a plurality of network storages into a single-view file system for a client and obtains information about an object's storage location without inquiring of a resource manager. The method determines a network storage that should store an object based on a hash value generated from a logical identifier for the object to be accessed. While accessing the object, the method computes the hash value for the object's logical identifier to determine a network storage that should process an access request. Consequently, the method eliminates the need to inquire the object's storage location when the access request is issued. Further, the method eliminates the need to maintain the object's storage location when the number of servers is increased or decreased, thus providing easy management.

Abstract: Database synchronization processing is completed within a reasonable time, using narrow-band network that connects a primary site to a secondary site, to reduce the running cost of a system. A primary DBMS has a transaction executing unit for reading a primary DB of a primary storage system to update data as requested in an update request, and a write unit for writing the updated data in the primary storage system. The primary storage system includes an unnecessary information removing unit for overwriting an unused area in the written data successively with one of a preset character and a preset value. The primary storage system is connected, via a network, to a second storage system which stores a copy of the primary DB. The primary storage system is connected to the network via a network device which has a data compression unit for compressing a succession of the same value.

Abstract: When a public line is used for a remote copy function of storage in a disaster recovery (DR) system, the online performance is degraded due to the increase and decrease of the line utilization rate. Therefore, it is desired to change the remote copy function depending on the line utilization rate. Also, there is the possibility of data loss if disaster occurs during the copy between storage devices. Therefore, it is desired to perform the processing to detect the data status immediately before the occurrence of the disaster. By switching the synchronous transmission and the asynchronous transmission in accordance with the increase and decrease of the response time of the remote copy function between storage devices, the online performance of the primary site can be maintained without being influenced by the line utilization rate, and the data loss can be detected based on the used remote copy function.

Abstract: Provided is a technique of setting up a disaster recovery system. In a log-based disaster recovery system including a first site for processing data and a second site for storing a backup of the first site, the first site has a volume where data is stored and a volume that is made quiescent. The disaster recovery system accepts data updates while sequentially copying initial data from the quiescent volume to the second site. A copy of a log of the first site is kept in the second site and is synchronized with the original log. When data of the first site is updated and corresponding initial data has not been copied to the second site, the data to be updated is preferentially copied to the second site. A log is applied to the copied data, thereby matching data of the second site with data of the first site.

Abstract: A recovery of a secondary DB is executed by a log including a update difference of a primary DB, and a command is executed by adding the command to the log and analyzing the log by a secondary site. An operation command execution in the secondary site is applied to the DB having the consistency in the transaction at the same timing as a primary site or an intended timing, by transferring and executing the operation command via the log. In the case that the command is constituted by a snap shot generating instruction, a plurality of volumes of a mirror set forming a secondary storage apparatus are set to a pair state and the secondary DB is written in each of the volumes and synchronized, and the mirror set is set to a split state after the synchronization is finished, whereby a secondary DB is stored.

Abstract: Even when information lifecycle management is applied to management object data of a database management system, inquiry service performance offered by the database management system can be guaranteed. Data arrangement managing system performs data arrangement settings in respect of management object data of the database management system and has a data arrangement setting creating module for determining possible data arrangement candidates and a data arrangement setting exchanging module for transferring the data arrangement candidates to the database management system. In the database management system, in respect of the individual data arrangement candidates transmitted to the database management system, execution profiles of service presupposing the candidates are created which are decided as to whether to satisfy a condition on database performance designated by a user and a narrowing down module narrows down the candidates to only data arrangement candidates satisfying the condition.

Abstract: In a storage device, a method is provided for preventing the risk of data loss and a significant decrease of writing speed due to area shrinkage when erased erase blocks have become fewer. A process of allocating a new page includes determining whether the length of a deallocated pages list is longer than n pages. If the list length is longer, one page is allocated from the deallocated pages list. If the list length is shorter, a capacity shortage error returns. Deleting a file using an erased pages list includes determining whether a page to be processed is emptied by deleting the file. If not so, the file is deleted from the page. If so, the contents of the last page-a in occupied pages are copied to the page, the page-a is written with data for erasure, and any erase block included in the page-a is made erasable.

Abstract: Since no control of accesses made by a computer as accesses to a storage apparatus is executed, the computer can be used illegally to steal and improperly change data stored in the storage apparatus. Thus, an access-control mechanism external to the computer is constructed to solve this problem. That is to say, the control of accesses is executed in the storage apparatus and a network apparatus for each program executed by the computer. In order to enhance the implementability of such control of accesses, the control is executed without extending a variety of protocols of communications among the computer, the network apparatus and the storage apparatus. By implementing the control of accesses in this way, a program other than programs specified in advance is not capable of making an access to data stored in the storage apparatus. Thus, even if the computer is used illegally, data stored in the storage apparatus can be prevented from being stolen and changed improperly.

Abstract: A technology capable of preventing a problem which occurs when log writing of a preceding transaction fails while reducing waiting time of a subsequent transaction is provided. A database control method for releasing locking of data held by a transaction upon reception of a transaction completion instruction from an operation terminal or the like by a database is provided. The database includes an exclusive control module, a log output module, and a log buffer. The log output module stores a transaction completion log in the log buffer upon reception of the transaction completion instruction from the operation terminal. The exclusive control module releases locking held by the transaction upon reception of storage of the transaction completion log in the log buffer.