옵티마이져 #
RBO : Rule based Optimizer
CBO : Cost Based Optimizer
script history #
sqlplus system/test123@abc SQL> create user 본인이름 identified by test123; SQL> GRANT dba to 본인이름; SQL> conn 본인이름/test123@abc SQL> show user SQL> create table emp as select * from scott.emp; SQL> create table dept as select * from scott.dept; SQL> explain plan for select ename,dname from emp,dept where emp.deptno = dept.deptno; SQL> select operation, options , object_name from plan_table; SQL> select * from table (dbms_xplan.display); ************************** SQL> set autot on SQL> select ename,sal from emp where deptno= 10; SQL> set autot traceo SQL> select * from dept;