用数据泵做导入时，报如下错误：
ORA-39001: invalid argument value
ORA-01775: looping chain of synonyms
ORA-01775: looping chain of synonyms
调查：
SQL>select owner, object_name, object_type, status from dba_objects where object_name like '%SYS_IMPORT%';
OWNER
------------------------------
OBJECT_NAME
---------------------------------------------------------------------------
OBJECT_TYPE STATUS
------------------- -------
PUBLIC
SYS_IMPORT_FULL_01
SYNONYM VALID
OWNER
------------------------------
OBJECT_NAME
---------------------------------------------------------------------------
OBJECT_TYPE STATUS
------------------- -------
PUBLIC
SYS_IMPORT_FULL_01
SYNONYM VALID
原因：SYS_IMPORT_FULL_01是impdp时产生的同义词。如果impdp正常完成退出，它会被自动清除掉。如果，impdp异常中断，它会保留。
解决方案：
把它手动drop掉，再做IMPDP导入。
SQL>drop public synonym sys_import_full_01;
针对不同schema级别的导入，对应的同义词是sys_import_schema_01