Method and system of database management for replica database
First Claim
1. A data processing unit including a database management system operating on an external storage unit provided with multiple storage areas for storing data, a multiple write mechanism allowing multiple writes of same data, a multiple write cancellation mechanism separating multi-written areas at a desired time to allow independent reading and writing as different control areas, and a physical copy mechanism that allows copying of data stored in the multiple storage areas, the data processing unit comprising:
- a first data synchronizing system for writing in a data cache, and then to the multiple storage areas in the external storage unit, unwritten data, and for delaying writing updated data to the multiple storage areas;
a first data synchronization canceling system for restarting an update of the data under control of the first data synchronizing system;
a second data synchronizing system for erasing all data in the data cache when all transactions in progress are completed, and for temporarily prohibiting access by a newly generated transaction while the erasing is occurring; and
a second data synchronization canceling system for restarting data access under control of the second synchronizing system.
1 Assignment
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Accused Products
Abstract
When a database area multi-written or replicated in an external storage unit is separated, a database management system writes consistent data into the external storage unit. A method and system capable of controlling a timing of separating the replicated database area is provided. Furthermore, new data directory information necessary to access the replicated database is dynamically added based on the data directory information of the replication source database. A method and system capable of selecting whether to access the database which is the source of the replication or access the replicated database are provided. Thus, when the database area multi-written or replicated in an external storage unit is separated and physical replicated databases are created, it is possible to maintain consistency of the replicated databases while continuing transaction processing.
65 Citations
7 Claims
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1. A data processing unit including a database management system operating on an external storage unit provided with multiple storage areas for storing data, a multiple write mechanism allowing multiple writes of same data, a multiple write cancellation mechanism separating multi-written areas at a desired time to allow independent reading and writing as different control areas, and a physical copy mechanism that allows copying of data stored in the multiple storage areas, the data processing unit comprising:
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a first data synchronizing system for writing in a data cache, and then to the multiple storage areas in the external storage unit, unwritten data, and for delaying writing updated data to the multiple storage areas; a first data synchronization canceling system for restarting an update of the data under control of the first data synchronizing system; a second data synchronizing system for erasing all data in the data cache when all transactions in progress are completed, and for temporarily prohibiting access by a newly generated transaction while the erasing is occurring; and a second data synchronization canceling system for restarting data access under control of the second synchronizing system. - View Dependent Claims (2)
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3. A data processing unit including a database management system operating on an external storage unit provided with multiple storage areas for storing data, a multiple write mechanism allowing multiple writes of same data, a multiple write cancellation mechanism separating multi-written areas at a desired time to allow independent reading and writing as different control areas, and a physical copy mechanism that allows copying of data stored in the multiple storage areas, and including a first data synchronizing system for writing in a data cache, and then to the multiple storage areas in the external storage unit, unwritten data, and for delaying writing updated data to the multiple storage areas, and a first data synchronization canceling system for restarting an update of the data under control of the first data synchronizing system, the first data synchronizing system including:
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a first function which allows updating of the transactions through the data cache in response to a data access request from a transaction; a second function which allows updating of the transactions then in progress, but prohibits updating the newly generated transaction; a third function which allows referencing of all transactions and updating of the transaction in progress, but prohibits updating the newly generated transaction; a fourth function which allows referencing all transactions, and allows updating all transactions, but only in the data cache; a fifth function which allows updating the transaction in progress, and prohibits updating a newly generated transaction; and a sixth function which allows updating the transaction in progress, and delays updating the newly generated transaction. - View Dependent Claims (4, 5)
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6. A data processing unit wherein in a database management system operating on data in an external storage unit having multiple storage areas for storing data, having a multiple write mechanism allowing multiple write of same data, and having a multiple write cancellation mechanism that separates multi-written areas at a specified time to allow independent reading and writing as different control areas, and having a physical copy mechanism that allows copying of data stored in respective areas, the data processing unit comprising:
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a data directory information dynamic copying subsystem for copying, based on data directory information registered in the database management system, common information independent of an access path of the storage area, and rewriting the common information only of the access path to the storage area to another storage area, and for dynamically adding second data directory information which includes a new name of first data directory information of a source of the common information; a data directory information dynamic registering subsystem capable of registering the second data directory information in the database management system; and an access target allocating subsystem for changing a database access request from an application program to be executed according to the first data directory information to cause the database access request to be executed according to the second data directory information. - View Dependent Claims (7)
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Specification