多个表关联或者有视图套视图，快速检查SQL语句中所有的表统计信息是否过期
现有如下SQL：
select * from emp e,dept d where e.deptno=d.deptno;
先用explain plan for命令，在plan_table中生成SQL的执行计划：
SQL> explain plan for select * from emp e,dept d where e.deptno=d.deptno;
Explained.
然后使用下面脚本检查SQL语句中所有的表的统计信息是否过期：
SQL> select owner, table_name, object_type, stale_stats, last_analyzed
from dba_tab_statistics
where (owner, table_name) in
(select object_owner, object_name
from plan_table
where object_type like '%TABLE%'
union
select table_owner, table_name
from dba_indexes
where (owner, index_name) in
(select object_owner, object_name
from plan_table
where object_type like '%INDEX%'));
OWNER TABLE_NAME OBJECT_TYP STALE_STATS LAST_ANALYZED
---------- ---------- ---------- --------------- ------------------
SCOTT DEPT TABLE NO 05-DEC-16
SCOTT EMP TABLE YES 22-OCT-16
最后可以使用下面脚本检查SQL语句中表统计信息的过期原因：
select *
from all_tab_modifications
where (table_owner, table_name) in
(select object_owner, object_name
from plan_table
where object_type like '%TABLE%'
union
select table_owner, table_name
from dba_indexes
where (owner, index_name) in
(select object_owner, object_name
from plan_table
where object_type like '%INDEX%'));