ORA-01624

Error: ORA-01624: log string needed for crash recovery of thread string

Causa: A log cannot be dropped or cleared until the thread's checkpoint has advanced out of the log.

Acción: If the database is not open then open it. Crash recovery will advance the checkpoint. If the database is open force a global checkpoint. If the log is corrupted so that the database cannot be opened, it may be necessary to do incomplete recovery until cancel at this log.