首页 / 数据库 / MySQL / Oracle 11g如何清除share pool中某条SQL的执行计划
以前在Oracle 10g数据库上,如果遇到绑定窥探导致执行计划慢的情况,想要清除某条SQL的执行计划,让它硬解析,找了很久都没有找到直接操作share pool的方法(总不能alter system flush shared_pool),只能通过对表ddl使SQL硬解析。现在终于找到了,使用sys.dbms_shared_pool.purge,在11g下可以直接使用,但在10g上需要alter session set events "5614566 trace name context forever"。SQL> select * from v$version;BANNER -------------------------------------------------------------------------------- Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production PL/SQL Release 11.2.0.1.0 - Production CORE 11.2.0.1.0 Production TNS for Linux: Version 11.2.0.1.0 - Production NLSRTL Version 11.2.0.1.0 - Production SQL> drop table test purge; SQL> create table test as select * from dba_objects; SQL> exec dbms_stats.gather_table_stats(user,"test"); SQL> select /*gg*/count(*) from test; COUNT(*) ---------- 79747 SQL> col SQL_TEXT format a35 SQL> col ADDRESS format a18 SQL> col HASH_VALUE format a10 SQL> select s.SQL_TEXT, s.ADDRESS, s.HASH_VALUE||"" from v$sqlarea s where sql_text like "select /*gg*/count(*) from test%"; SQL_TEXT ADDRESS S.HASH_VALUE||"" ----------------------------------- ------------------ -------------------------------- select /*gg*/count(*) from test 0000000300B06D70 728448230 SQL> exec sys.dbms_shared_pool.purge("0000000300B06D70,728448230","c"); PL/SQL 过程已成功完成。 SQL> select s.SQL_TEXT, s.ADDRESS, s.HASH_VALUE||"" from v$sqlarea s where sql_text like "select /*gg*/count(*) from test%"; 未选定行更多Oracle相关信息见Oracle 专题页面 http://www.linuxidc.com/topicnews.aspx?tid=12本文永久更新链接地址