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ORA-49100: Failed to process event statement […]

SQL> alter session set events 'sql_trace [sql:8x615vyks733p] wait=false, bind=false, planstat=never';
ORA-49100: Failed to process event statement [sql_trace [sql:8x615vyks733p] wait=false, bind=false, planstat=never] 
ORA-49104: [PLANSTAT] is not a valid argument for event [sql_trace]

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