一直打RU补丁，未真正了解过RUR与RU之前关系，今天有机会与小伙伴讨论，修正了之前误区，特此记录。

从 2017 年 7 月开始，Oracle 对数据库和 GI(Grid Infrastructure) 12.2 及之后版本的主动修补程序进行了更改。Oracle 从 12.2 版本开始补丁不在使用 PSU、SPU 的称呼了，取而代之的为 RU (Release Updates) 和 RUR (Release Update Revisions)

（1）RU、RUR均可独立打，均为累积性。RUR无需前置RU即可独立打补丁。

（2）RUR与RU可以互相转换打补丁序列，但需要遵循补丁后两位之和大于已打补丁，例如：

Example 1:
    source - 18.2.2     <<<<< sum of second and third fields is "4"
    destination - 18.5.0     <<<<< sum of second and third fields is "5"
    conclusion: destination "5" is greater than or equal to source "4" so it is OK to move

Example 2:
    source - 18.2.2     <<<<< sum of second and third fields is "4"
    destination - 18.3.0     <<<<< sum of second and third fields is "3"
    conclusion: destination "3" is less than source "4" so a patch application error is issued

（3）RUR最多可以有两次，即对RU的生命周期延长两个季度。

详细请参考附件以及下面链接：

Release Update Introduction and FAQ (Doc ID 2285040.1).pdf

https://www.modb.pro/db/27255

Oracle 12.2之后补丁RU RUR概要