保证优化器是CBO模式下,执行DBMS_SQLTUNE包进行sql优化需要有advisor的权限：
这里对DBMS_SQLTUNE不做描述，请看实验：
create table aaa as select a. from sys.all_objects a;
create table bbb as select a. FROM dba_tables a;
运行多次 模拟数据：
insert into aaa select a. from dba_objects a;
insert into bbb select a. FROM dba_tables a;
commit;
SQL> DECLARE
my_task_name VARCHAR2(30);
my_sqltext CLOB;
BEGIN
my_sqltext := 'select count(*) from aaa a, bbb b where a.object_name=b.table_name';
my_task_name := DBMS_SQLTUNE.CREATE_TUNING_TASK(
sql_text => my_sqltext,
user_name => 'XXX', -- 大写
scope => 'COMPREHENSIVE',
time_limit => 60,
task_name => 'tuning_sql_test',
description => 'Task to tune a query on a specified table');
DBMS_SQLTUNE.EXECUTE_TUNING_TASK( task_name => 'tuning_sql_test');
END;
/
SQL> exec dbms_sqltune.execute_tuning_task('tuning_sql_test');
SQL> SELECT task_name,status FROM USER_ADVISOR_TASKS WHERE task_name ='tuning_sql_test';
SQL> SET LONG 999999
SQL> set serveroutput on size 999999
SQL> SET LINESIZE 100
SQL> SELECT DBMS_SQLTUNE.REPORT_TUNING_TASK( 'tuning_sql_test') from DUAL;
SQL>exec dbms_sqltune.drop_tuning_task('tuning_sql_test');