发明名称 |
Sharing snapshots for consistent reads |
摘要 |
A method and apparatus for supplying data from a database to a group of transactions is provided. A value is maintained for the group of transactions. The value indicates a target snapshot of the database. When a transaction within the group of transactions accesses a data item, it is determined whether the transaction can use the target snapshot. If the transaction can use the target snapshot, then the transaction is supplied a version of the data item that belongs to the target snapshot. If the transaction cannot use the target snapshot, then the transaction is supplied a version of the data item other than the version of the data item that belongs to the target snapshot. Trying to supply data from the same snapshot to all of the transactions in the group increases the likelihood that the transactions will be able to use the same version of any given data item. Consequently, fewer reconstruction operations will have to be performed, and dynamic memory is less likely to become filled with different versions of the same data items.
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申请公布号 |
US5956731(A) |
申请公布日期 |
1999.09.21 |
申请号 |
US19970842169 |
申请日期 |
1997.04.23 |
申请人 |
ORACLE CORPORATION |
发明人 |
BAMFORD, ROGER;KLOTS, BORIS;SWART, GARRET |
分类号 |
G06F9/46;G06F17/30;(IPC1-7):G06F17/30 |
主分类号 |
G06F9/46 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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