各位大侠，请教个问题，我的物化视图在刷新时报：
BEGIN dbms_mview.refresh('TB_DATA','c'); END;
*
ERROR at line 1:
ORA-12008: error in materialized view refresh path
ORA-12801: error signaled in parallel query server
ORA-02063: preceding 2 lines from DL_CCC
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2255
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2461
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2430
ORA-06512: at line 1
怎么解决？
