ORACLE cannot fetch plan for SQL_ID

今天做SQL执行计划测试的时候，发现sqlplus无法正常打印执行计划，根据网上资料整理如下：

.....

SYS@orcl> select *
  2     from table(
  3           dbms_xplan.display_cursor( format=> 'allstats last' )
  4           )
  5   /


PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------
SQL_ID  9babjv8yq8ru3, child number 0


BEGIN DBMS_OUTPUT.GET_LINES(:LINES, :NUMLINES); END;


NOTE: cannot fetch plan for SQL_ID: 9babjv8yq8ru3, CHILD_NUMBER: 0
      Please verify value of SQL_ID and CHILD_NUMBER;
      It could also be that the plan is no longer in cursor cache (check v$sql
_plan)

注意： 标红的SQL_ID确实不存在，原因是SQLPLUS打开了SERVEROUTPUT ,TOM的解释如下：

do you see the sql it is showing - dbms_output.get_lines.... 

the last sql your session executed was in fact that call - sqlplus does that when you have set serveroutput on 


issue  解决方法：

set serveroutput off 

and try it...   再次查询

-------------------------------

Dylan    Presents.