Mega Code Archive
Set autotrace traceonly explain for bitmap index
<![CDATA[
SQL>
SQL> CREATE TABLE EMP(
2 EMPNO NUMBER(4) NOT NULL,
3 ENAME VARCHAR2(10),
4 JOB VARCHAR2(9),
5 MGR NUMBER(4),
6 HIREDATE DATE,
7 SAL NUMBER(7, 2),
8 COMM NUMBER(7, 2),
9 DEPTNO NUMBER(2)
10 );
Table created.
SQL> INSERT INTO EMP VALUES(2, 'Jack', 'Tester', 6,TO_DATE('20-FEB-1981', 'DD-MON-YYYY'), 1600, 300, 30);
1 row created.
SQL> INSERT INTO EMP VALUES(3, 'Wil', 'Tester', 6,TO_DATE('22-FEB-1981', 'DD-MON-YYYY'), 1250, 500, 30);
1 row created.
SQL> INSERT INTO EMP VALUES(4, 'Jane', 'Designer', 9,TO_DATE('2-APR-1981', 'DD-MON-YYYY'), 2975, NULL, 20);
1 row created.
SQL> INSERT INTO EMP VALUES(5, 'Mary', 'Tester', 6,TO_DATE('28-SEP-1981', 'DD-MON-YYYY'), 1250, 1400, 30);
1 row created.
SQL> INSERT INTO EMP VALUES(7, 'Chris', 'Designer', 9,TO_DATE('9-JUN-1981', 'DD-MON-YYYY'), 2450, NULL, 10);
1 row created.
SQL> INSERT INTO EMP VALUES(8, 'Smart', 'Helper', 4,TO_DATE('09-DEC-1982', 'DD-MON-YYYY'), 3000, NULL, 20);
1 row created.
SQL> INSERT INTO EMP VALUES(9, 'Peter', 'Manager', NULL,TO_DATE('17-NOV-1981', 'DD-MON-YYYY'), 5000, NULL, 10);
1 row created.
SQL> INSERT INTO EMP VALUES(10, 'Take', 'Tester', 6,TO_DATE('8-SEP-1981', 'DD-MON-YYYY'), 1500, 0, 30);
1 row created.
SQL> INSERT INTO EMP VALUES(13, 'Fake', 'Helper', 4,TO_DATE('3-DEC-1981', 'DD-MON-YYYY'), 3000, NULL, 20);
1 row created.
SQL>
SQL> CREATE TABLE DEPT(
2 DEPTNO NUMBER(2),
3 DNAME VARCHAR2(14),
4 LOC VARCHAR2(13)
5 );
Table created.
SQL>
SQL> INSERT INTO DEPT VALUES (10, 'ACCOUNTING', 'NEW YORK');
1 row created.
SQL> INSERT INTO DEPT VALUES (20, 'RESEARCH', 'DALLAS');
1 row created.
SQL> INSERT INTO DEPT VALUES (30, 'SALES', 'CHICAGO');
1 row created.
SQL> INSERT INTO DEPT VALUES (40, 'OPERATIONS', 'BOSTON');
1 row created.
SQL>
SQL> alter table dept add constraint dept_pk primary key(deptno);
Table altered.
SQL>
SQL> create bitmap index emp_bm_idx on emp( d.dname)from emp e, dept d where e.deptno = d.deptno
2 /
SQL> begin
2 dbms_stats.set_table_stats( user, 'EMP', numrows => 1000000, numblks => 300000 );
3 dbms_stats.set_table_stats( user, 'DEPT',numrows => 100000, numblks => 30000 );
4 end;
5 /
PL/SQL procedure successfully completed.
SQL>
SQL> set autotrace traceonly explain
SQL>
SQL> select count(*) from emp, dept where emp.deptno = dept.deptno and dept.dname = 'SALES'
2 /
Execution Plan
----------------------------------------------------------
Plan hash value: 1546158010
------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost |
------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 35 | 50088 |
| 1 | SORT AGGREGATE | | 1 | 35 | |
|* 2 | HASH JOIN | | 10M| 333M| 50088 |
|* 3 | TABLE ACCESS FULL| DEPT | 1000 | 22000 | 4554 |
| 4 | TABLE ACCESS FULL| EMP | 1000K| 12M| 45533 |
------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("EMP"."DEPTNO"="DEPT"."DEPTNO")
3 - filter("DEPT"."DNAME"='SALES')
Note
-----
- cpu costing is off (consider enabling it)
SQL>
SQL> set autotrace off
SQL>
SQL> drop table emp;
Table dropped.
SQL> drop table dept;
Table dropped.
SQL>
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