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ORA-01353:

existing Logminer session
Cause: An attempt was made to execute DBMS_LOGMNR_D.SET_TABLESPACE while a Logminer session(s) was active.
Action: First cause all Logminer sessions to be closed. A Logminer session can exist as a result of executing DBMS_LOGMNR.START_LOGMNR or as the result of using Oracle features such as Data Guard SQL Apply or Streams which use Logminer. Next, execute DBMS_LOGMNR_D.SET_TABLESPACE.