Oracle : Ошибка ORA-28593

"agent control utility: command terminated with error"
*Cause: An error occurred during the processing of the command. There
could be several causes. A SET or an UNSET command could have
been issued after the agent was started. This is illegal. The
user may have attempted to start two agents with the same SID
value or the user could have attempted to shutdown an agent
that is no longer running.
*Action: If the user wishes to issue a SET or an UNSET command, he should
make sure the agent is shutdown first by issuing the SHUTDOWN

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