ORA-38755: Flashback is already turned on for this tablespace.
Cause: An attempt was made to turn on flashback database logging for a tablespace that already has flashback turned on.
Action: No action required.
ORA-38755是Oracle数据库的一个错误，在运行某一个命令时出现。当用户希望在一个表空间上启用flashback功能时，出现此错误表示该表空间上已经启用了flashback功能。