文档解释
ORA-19694: some changed blocks were not found in the change tracking file
Cause: A backup or copy found that some changed blocks had not been recorded in the change tracking file. The details of which files and blocks are affected will be in an Oracle trace file.
Action: This indicates that there is a problem with the change tracking feature. Disable change tracking and re-start the backup.
ORA-19694表示由于某些变更块没有找到更改跟踪文件，导致更改跟踪文件无法替换文件。
官方解释
通常情况下，此错误是使用exp/imp迁移数据库时遇到的。
一般处理方法及步骤
1、检查exp/imp时操作是否正确；
2、检查源、目标数据库数据文件是否正确；
3、检查更改跟踪文件是否正确；
4、重新检查跟踪文件，看是否有漏掉的段被跟踪；
5、尝试使用替换原始数据文件的功能。
