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在9i中因为某个执行计划因为Oracle Peeking绑定变量的控制导致现有的执行计划不正确,需要清除掉这条sql语句的执行计划.在10g中提供了dbms_shared_pool.purge,但是在9i中未提供好的方法。

一般来说可以通过对相关表的DDL操作,收集统计信息,授权操作可以实现清除对于表执行计划.注:这些操作不会只清空特定SQL执行计划,而是会清除该表相关的所有执行计划,所以操作需要慎重(影响肯定比flush shared_pool小)

模拟测试数据

SQL> create table t_xifenfei (id number,name varchar2(100));

Table created.

SQL> insert into t_xifenfei values(1,'www.xifenfei.com');

1 row created.

SQL> commit;

清除执行计划1:修改表结构

SQL> alter system flush shared_pool;

System altered.

SQL> select * from t_xifenfei;

ID NAME

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

1 www.xifenfei.com

SQL> select sql_text,HASH_VALUE from v$sqlAREA where sql_text like '%xifenfei';

SQL_TEXT HASH_VALUE

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

select * from t_xifenfei 1067507827

SQL> select OPERATION from v$sql_plan where hash_value=1067507827;

OPERATION

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

SELECT STATEMENT

TABLE ACCESS

SQL> alter table t_xifenfei add fei varchar2(10);

Table altered.

SQL> alter table t_xifenfei drop COLUMN fei;

Table altered.

SQL> select sql_text,HASH_VALUE from v$sqlAREA where sql_text like '%xifenfei';

SQL_TEXT HASH_VALUE

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

select * from t_xifenfei 1067507827

SQL> select count(*) from v$sql_plan where hash_value=1067507827;

COUNT(*)

----------

0

清除执行计划2:重新收集统计信息

--DBMS_STATS收集统计信息

SQL> alter system flush shared_pool;

System altered.

SQL> select * from t_xifenfei;

ID NAME

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

1 www.xifenfei.com

SQL> select sql_text,HASH_VALUE from v$sqlAREA where sql_text like '%xifenfei';

SQL_TEXT HASH_VALUE

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

select * from t_xifenfei 1067507827

SQL> select OPERATION from v$sql_plan where hash_value=1067507827;

OPERATION

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

SELECT STATEMENT

TABLE ACCESS

SQL> EXEC DBMS_STATS.gather_table_stats(user,'T_XIFENFEI');

PL/SQL procedure successfully completed.

SQL> select sql_text,HASH_VALUE from v$sqlAREA where sql_text like '%xifenfei';

SQL_TEXT HASH_VALUE

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

select * from t_xifenfei 1067507827

SQL> select OPERATION from v$sql_plan where hash_value=1067507827;

no rows selected

--analyze收集统计信息(不推荐)

SQL> alter system flush shared_pool;

System altered.

SQL> select * from t_xifenfei;

ID NAME

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

1 www.xifenfei.com

SQL> select sql_text,HASH_VALUE from v$sqlAREA where sql_text like '%xifenfei';

SQL_TEXT HASH_VALUE

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

select * from t_xifenfei 1067507827

SQL> select OPERATION from v$sql_plan where hash_value=1067507827;

OPERATION

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

SELECT STATEMENT

TABLE ACCESS

SQL> analyze table t_xifenfei compute statistics;

Table analyzed.

SQL> select sql_text,HASH_VALUE from v$sqlAREA where sql_text like '%xifenfei';

SQL_TEXT HASH_VALUE

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

select * from t_xifenfei 1067507827

SQL> select OPERATION from v$sql_plan where hash_value=1067507827;

no rows selected

清除执行计划3:创建INDEX

SQL> alter system flush shared_pool;

System altered.

SQL> select * from t_xifenfei;

ID NAME

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

1 www.xifenfei.com

SQL> select sql_text,HASH_VALUE from v$sqlAREA where sql_text like '%xifenfei';

SQL_TEXT HASH_VALUE

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

select * from t_xifenfei 1067507827

SQL> select OPERATION from v$sql_plan where hash_value=1067507827;

OPERATION

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

SELECT STATEMENT

TABLE ACCESS

SQL> create index i_txifenfei on t_xifenfei(id) online;

Index created.

SQL> drop index i_txifenfei ;

Index dropped.

SQL> select sql_text,HASH_VALUE from v$sqlAREA where sql_text like '%xifenfei';

SQL_TEXT HASH_VALUE

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

select * from t_xifenfei 1067507827

SQL> select OPERATION from v$sql_plan where hash_value=1067507827;

no rows selected

清除执行计划3:GRANT/REVOKE操作

SQL> alter system flush shared_pool;

System altered.

SQL> select * from t_xifenfei;

ID NAME

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

1 www.xifenfei.com

SQL> select sql_text,HASH_VALUE from v$sqlAREA where sql_text like '%xifenfei';

SQL_TEXT HASH_VALUE

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

select * from t_xifenfei 1067507827

SQL> select OPERATION from v$sql_plan where hash_value=1067507827;

OPERATION

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

SELECT STATEMENT

TABLE ACCESS

SQL> GRANT SELECT ON T_XIFENFEI TO SYSTEM;

Grant succeeded.

SQL> select sql_text,HASH_VALUE from v$sqlAREA where sql_text like '%xifenfei';

SQL_TEXT HASH_VALUE

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

select * from t_xifenfei 1067507827

SQL> select OPERATION from v$sql_plan where hash_value=1067507827;

no rows selected

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操作有风险，动手需谨慎

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最权威、专业的Oracle案例资源汇总之Oracle数据库9I中清除特定表相关执行计划案例