Cause: Attempt to open thread failed because it is necessary to switch
redo generation to another online log, but all the other logs are
being cleared or need to be archived before they can be used.
Action: If the ALTER DATABASE CLEAR LOGFILE command is still active then
wait for it to complete. Otherwise reissue the CLEAR command. If
there are other online logs for the thread, that are not being
cleared, then archive the logs.