Oracle : Ошибка ORA-38740

"Usable blocks value %s is not valid."
*Cause: A flashback database log file header contained a usable
blocks value greater than the file size. The flashback
database log file file is corrupt.
*Action: If you are doing a FLASHBACK DATABASE, then the flashback
cannot be performed because of the corrupted log. A restore
and an incomplete recovery must be performed instead.

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