Oracle入门教程：Redo 和Undo的区别和联系详细解释-Mysql Tutorial-php.cn

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Oracle入门教程：Redo 和Undo的区别和联系详细解释

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Jun 07, 2016 pm 05:06 PM

oracle database

Oracle入门教程：Redo 和Undo的区别和联系详细解释

管理目标是避免出现两种错误：

vORA-01650: unable to extend rollback segment

vORA-01555: snapshot too old

管理方式落实为正确配置三个参数和一个还原表空间属性：

UNDO_MANAGEMENT

UNDO_TABLESPACE

UNDO_RETENTION

RETENTION GUARANTEE

9.5 提交和回滚处理

commit操作需要的时间很“平”，与事务的大小没有直接关系。

rollback操作所需的时间与事务所修改的数据量直接相关。

因此在设计事务时，不要考虑事务的大小和多少，而应以所执行的操作是否构成一个逻辑工作单元作依据。

提交前后完成的操作

，

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