undo保留时间的几个相关参数

参考文档： https://docs.oracle.com/cd/E11882_01/server.112/e40402/initparams265.htm#REFRN10225 https://docs.oracle.com/cd/E11882_01/server.112/e40402/initparams264.htm#REFRN10224 MOS 文档 ID 1526122.1 MOS 文档

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