1、在本地创建本地命名，连接到讲师机数据。
在 e:appadministratorproduct11.2.0dbhome_1 etwordadmin nsnames.ora
文件中加入以下内容
test =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 172.16.11.209)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = orcl)
)
)
用sqlplus 测试是否可以连接
sqlplus test/test@test
连接到:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
With the Partitioning, Automatic Storage Management, OLAP, Data Mining
and Real Application Testing options
SQL>
2、用test/test 用户登录PL/SQL Developer
打开一个SQL窗口
delete from plan_table;
commit;
explain plan for
SELECT
c2.order_num,c2.customer_id, c2.create_date, c1.product_spec
FROM product c1, order_mat c2, order_detl c3
where c3.order_id=c2.order_id and c1.product_id=c3.product_id and
c1.product_spec='QSP3N4'and c2.create_date between
to_date('2009-01-01','yyyy-mm-dd') and to_date('2009-12-01','yyyy-mm-dd');
SELECT * FROM table(DBMS_XPLAN.DISPLAY);
看相关的执行计划，发现有大量的全部扫描和hash jion
Plan hash value: 3203830265
--------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 18 | 1314 | 49435 (1)| 00:09:54 |
| 1 | NESTED LOOPS | | | | | |
| 2 | NESTED LOOPS | | 18 | 1314 | 49435 (1)| 00:09:54 |
|* 3 | HASH JOIN | | 122 | 4026 | 49191 (1)| 00:09:51 |
|* 4 | TABLE ACCESS FULL | PRODUCT | 1 | 20 | 694 (1)| 00:00:09 |
| 5 | TABLE ACCESS FULL | ORDER_DETL | 21M| 261M| 48431 (1)| 00:09:42 |
|* 6 | INDEX UNIQUE SCAN | ORDER_UK_ID | 1 | | 1 (0)| 00:00:01 |
|* 7 | TABLE ACCESS BY INDEX ROWID| ORDER_MAT | 1 | 40 | 2 (0)| 00:00:01 |
--------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
3 - access("C1"."PRODUCT_ID"="C3"."PRODUCT_ID")
4 - filter("C1"."PRODUCT_SPEC"='QSP3N4')
6 - access("C3"."ORDER_ID"="C2"."ORDER_ID")
7 - filter("C2"."CREATE_DATE">=TO_DATE(' 2009-01-01 00:00:00', 'syyyy-mm-dd
hh24:mi:ss') AND "C2"."CREATE_DATE"<=TO_DATE(' 2009-12-01 00:00:00', 'syyyy-mm-dd
hh24:mi:ss'))
3、修改优化器模式为first_rows;
delete from plan_table;
commit;
alter session set optimizer_mode=first_rows;
explain plan for
SELECT
c2.order_num,c2.customer_id, c2.create_date, c1.product_spec
FROM product c1, order_mat c2, order_detl c3
where c3.order_id=c2.order_id and c1.product_id=c3.product_id and
c1.product_spec='QSP3N4'and c2.create_date between
to_date('2009-01-01','yyyy-mm-dd') and to_date('2009-12-01','yyyy-mm-dd');
SELECT * FROM table(DBMS_XPLAN.DISPLAY);
Plan hash value: 3184491401
--------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 18 | 1314 | 49369 (1)| 00:09:53 |
| 1 | NESTED LOOPS | | | | | |
| 2 | NESTED LOOPS | | 18 | 1314 | 49369 (1)| 00:09:53 |
| 3 | NESTED LOOPS | | 122 | 4026 | 49125 (1)| 00:09:50 |
|* 4 | TABLE ACCESS FULL | PRODUCT | 1 | 20 | 694 (1)| 00:00:09 |
|* 5 | TABLE ACCESS FULL | ORDER_DETL | 122 | 1586 | 48431 (1)| 00:09:42 |
|* 6 | INDEX UNIQUE SCAN | ORDER_UK_ID | 1 | | 1 (0)| 00:00:01 |
|* 7 | TABLE ACCESS BY INDEX ROWID| ORDER_MAT | 1 | 40 | 2 (0)| 00:00:01 |
--------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
4 - filter("C1"."PRODUCT_SPEC"='QSP3N4')
5 - filter("C1"."PRODUCT_ID"="C3"."PRODUCT_ID")
6 - access("C3"."ORDER_ID"="C2"."ORDER_ID")
7 - filter("C2"."CREATE_DATE">=TO_DATE(' 2009-01-01 00:00:00', 'syyyy-mm-dd
hh24:mi:ss') AND "C2"."CREATE_DATE"<=TO_DATE(' 2009-12-01 00:00:00', 'syyyy-mm-dd
hh24:mi:ss'))
4、再次优化器模式为rule;
delete from plan_table;
commit;
alter session set optimizer_mode=rule;
explain plan for
SELECT
c2.order_num,c2.customer_id, c2.create_date, c1.product_spec
FROM product c1, order_mat c2, order_detl c3
where c3.order_id=c2.order_id and c1.product_id=c3.product_id and
c1.product_spec='QSP3N4'and c2.create_date between
to_date('2009-01-01','yyyy-mm-dd') and to_date('2009-12-01','yyyy-mm-dd');
SELECT * FROM table(DBMS_XPLAN.DISPLAY);
Plan hash value: 1465182523
--------------------------------------------------------
| Id | Operation | Name |
--------------------------------------------------------
| 0 | SELECT STATEMENT | |
| 1 | NESTED LOOPS | |
| 2 | NESTED LOOPS | |
| 3 | NESTED LOOPS | |
| 4 | TABLE ACCESS FULL | ORDER_DETL |
|* 5 | TABLE ACCESS BY INDEX ROWID| ORDER_MAT |
|* 6 | INDEX UNIQUE SCAN | ORDER_UK_ID |
|* 7 | INDEX UNIQUE SCAN | PRODUCT_PK_ID |
|* 8 | TABLE ACCESS BY INDEX ROWID | PRODUCT |
--------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
5 - filter("C2"."CREATE_DATE"<=TO_DATE(' 2009-12-01 00:00:00',
'syyyy-mm-dd hh24:mi:ss') AND "C2"."CREATE_DATE">=TO_DATE(' 2009-01-01
00:00:00', 'syyyy-mm-dd hh24:mi:ss'))
6 - access("C3"."ORDER_ID"="C2"."ORDER_ID")
7 - access("C1"."PRODUCT_ID"="C3"."PRODUCT_ID")
8 - filter("C1"."PRODUCT_SPEC"='QSP3N4')
Note
-----
- rule based optimizer used (consider using cbo)
5、再次优化器模式为为默认值，在语句中中加入提示，比较和第一步的代价
delete from plan_table;
commit;
alter session set optimizer_mode=all_rows;
explain plan for
SELECT /*+ use_hash(c2) */
c2.order_num,c2.customer_id, c2.create_date, c1.product_spec
FROM product c1, order_mat c2, order_detl c3
where c3.order_id=c2.order_id and c1.product_id=c3.product_id and
c1.product_spec='QSP3N4'and c2.create_date between
to_date('2009-01-01','yyyy-mm-dd') and to_date('2009-12-01','yyyy-mm-dd');
SELECT * FROM table(DBMS_XPLAN.DISPLAY);
Plan hash value: 1587320179
----------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
----------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 18 | 1314 | 59730 (1)| 00:11:57 |
|* 1 | HASH JOIN | | 18 | 1314 | 59730 (1)| 00:11:57 |
|* 2 | HASH JOIN | | 122 | 4026 | 49191 (1)| 00:09:51 |
|* 3 | TABLE ACCESS FULL| PRODUCT | 1 | 20 | 694 (1)| 00:00:09 |
| 4 | TABLE ACCESS FULL| ORDER_DETL | 21M| 261M| 48431 (1)| 00:09:42 |
|* 5 | TABLE ACCESS FULL | ORDER_MAT | 298K| 11M| 10538 (1)| 00:02:07 |
----------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - access("C3"."ORDER_ID"="C2"."ORDER_ID")
2 - access("C1"."PRODUCT_ID"="C3"."PRODUCT_ID")
3 - filter("C1"."PRODUCT_SPEC"='QSP3N4')
5 - filter("C2"."CREATE_DATE">=TO_DATE(' 2009-01-01 00:00:00',
'syyyy-mm-dd hh24:mi:ss') AND "C2"."CREATE_DATE"<=TO_DATE(' 2009-12-01
00:00:00', 'syyyy-mm-dd hh24:mi:ss'))