已索引

涉及版本

Oracle 文档 2335265.1 对 DB Link 和 SCN 补丁做了详细说明。现摘要如下：

文档 Note 2361478.1 对 Oracle databases versions 12.1.0.1, 11.2.0.3 and earlier 应该升级哪些 PSU 做了详细描述。

Oracle Database versions 12.1.0.1, 11.2.0.3, 11.1.0.7, 10.2.0.5 & 10.2.0.4 are strongly recommended to be patched to the patchset/PSU levels mentioned below before June 2019 to resolve potential future issues in terms of interoperability of dblinks.

补丁修改内容

These patches increase the database's current maximum SCN (system change number) limit. With the patches applied, this change in current maximum SCN limit will happen automatically starting 23rd June 2019.

Please note that the patches only increase the max limit but the current SCN is not impacted. So, if all your databases don’t have any major change in transaction rate, the current SCN would still remain below the current maximum SCN limit and database links between newer (or patched) and unpatched databases would continue to work.

如果不打补丁会如何？

If this patch is not applied, the unpatched database will have a lower SCN rate or lower current max SCN limit. The newer or patched databases will have higher SCN rate or higher current max SCN limit. When you open a dblink between these two databases, it has to sync the SCN levels of both the databases and if the SCN increase needed in the unpatched database for this sync is beyond it’s allowed SCN rate or current max SCN limit, then the dblink connection cannot be established. This situation will not rise immediately after the change, but can potentially arise any time after 23rd June 2019. And the dblink connections involving two unpatched databases or two older releases are not affected by this change.

P.S.

如果没有打补丁导致新老系统之间的数据库连接出现问题，将老系统打上补丁即可。

数据库版本 11.2.0.4, 12.1.0.2 and 12.2.0.1 不需要做任何事情，已经包含了所需要的所有补丁。