All Oracle Error CodesOracle DBA Forum

ORA-01622:

thread number must be specified - default not specific
Cause: The thread was not specified when adding a log, and the currently mounted thread was chosen by default at mount time. Since the current thread was not specified explicitly the user cannot know which thread the log will be added to.
Action: Explicitly specify the thread number either in the INIT.ORA parameter "thread", or in the add command.