#34_140730_TUNING_INVISIBLE INDEX

# INVISIBLE INDEX

n 수행 예제

SQL> demobld.sql SQL> create index emp_sal on emp(sal); SQL> alter index emp_sal invisible; SQL> select index_name,visibility from user_indexes; INDEX_NAME                     VISIBILIT ------------------------------ --------- EMP_SAL                        VISIBLE SALES500_RN                    VISIBLE SALES500_CHANNEL_PROFIT        VISIBLE SALES500_CHANNEL_ID            VISIBLE SALES500_AMOUNT_SOLD           VISIBLE ……………………………………………………… - invisible 유무 확인 SQL> select /* index(emp emp_sal) */ ename, sal, deptno      from emp      where sal=3000; - invisible 상태이기 때문에 full scan을 수행하는 것을 확인할 수 있다

문제30. 다시 emp_sal 인덱스를 옵티마이저가 보이도록 설정하고 보이는지 확인하시오

ALTER INDEX EMP_SAL visible;

select index_name,visibility from user_indexes;