Method and System of Database Management for Replica Database
First Claim
1. In a database management system, a data processing unit for handling a plurality of transactions in parallel, comprising:
- a plurality of storage areas for storing data;
a copy mechanism for copying data from a data cache into the plurality of storage areas;
a data synchronizer; and
a data synchronizer canceller,wherein the data synchronizer canceller identifies first transactions that are in progress at a first time, writes data on the data cache written by the first transactions into each of at least two storage areas when said each first transaction ends, and delays writing of data generated by second transactions which start after the first time to the storage areas until a second time,wherein the data synchronizer canceller stops the data synchronizer at the second time which is after all of the first transactions have ended and restarts writing the delayed data and new data generated by the second transactions to one of the at least two storage areas,wherein at least one of the at least two storage areas is separated from a control of the copy mechanism in response to a separate storage instruction during the period between the time when all first transactions have ended and the second time.
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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.
16 Citations
8 Claims
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1. In a database management system, a data processing unit for handling a plurality of transactions in parallel, comprising:
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a plurality of storage areas for storing data; a copy mechanism for copying data from a data cache into the plurality of storage areas; a data synchronizer; and a data synchronizer canceller, wherein the data synchronizer canceller identifies first transactions that are in progress at a first time, writes data on the data cache written by the first transactions into each of at least two storage areas when said each first transaction ends, and delays writing of data generated by second transactions which start after the first time to the storage areas until a second time, wherein the data synchronizer canceller stops the data synchronizer at the second time which is after all of the first transactions have ended and restarts writing the delayed data and new data generated by the second transactions to one of the at least two storage areas, wherein at least one of the at least two storage areas is separated from a control of the copy mechanism in response to a separate storage instruction during the period between the time when all first transactions have ended and the second time. - View Dependent Claims (2, 3, 4)
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5. In a database management system operating in a data processing unit which handles a plurality of transactions in parallel, a data processing method comprising:
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storing data in a plurality of storage areas; copying data from a data cache into the plurality of storage areas; identifying first transactions that are in progress at a first time; writing data on the data cache written by the first transactions into each of at least two storage areas when said each first transaction ends; delaying writing of data generated by second transactions which start after the first time to the storage areas; after all first transactions have ended, separating at least one storage area in response to a storage separate instruction; and restarting writing the delayed data and new data generated by the second transactions to one of the at least two storage areas, which is not separated after the separating step is completed. - View Dependent Claims (6, 7, 8)
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Specification