- 从10g以后，oracle连续公布了sql profile和sql baseline来实现SQL运行计划的控制。而且outline这个工具基本已经被Oracle废弃而且不在维护，可是无论怎么说。在10g以及11g版本号都还是能够使用。而且这个特性也一直使用的非常好。
- 10g以后建议使用sql profile或者sql baseline
- 因为眼下outline如今已经非常少使用，此文也尽量介绍有用的一部分
Outline将运行计划的hint集合保存在outline的表中（数据字典）。
当运行
SQL解析时。Oracle会与outline中的SQL比較，假设该SQL有保存的outline，则通过保存的hint集合生成指定运行计划。注意：
- SQL解析时，使用SQL文本却匹配数据字典outline保存的文本。此处匹配的方式为去掉SQL空格，忽略SQL大写和小写差别后。进行的比較。
- 比如,select * from dual 和SELECT * FROM dual这两个语句将使用相同的outline。
- 为避免在升级后某些SQL出现严重性能下降并且在短时间内不能优化的情况，我们能够使用outline的功能将原生产库中的sql运行计划实施在新的数据库上。
- 为避免SQL的运行计划在统计数据不准确的情况（如未能及时收集表或索引的统计信息）下导致变化从而引起的性能减少。
- 为避免easy由于Bind Peeking导致SQL运行计划变差从而引起的性能减少。
- 避免大规模分布实施的应用出现数据库版本号、配置等差别引起的优化器产生不同的运行计划。
- 某些Bug引起优化器生成较差的运行计划。在bug修复前我们能够使用outline来强制SQL的运行计划的正确。
- 早期优化器版本号从rule转换为cbo模式时，过渡期间用来维护业务稳定（运行计划稳定）
- outline存在在outln用户中，Outln用户是一个很重要的系统用户，其重要性跟sys，system一样。在不论什么情况下都不建议用户删除outln。否则会引起数据库错误。
- 优化器通过Outline生成运行计划前提是outline内全部hint都有效的。
- 仅仅有设置use_stored_outlines參数后才干启用outline。
- 使用字面值的sql的共享程度不高（没有使用绑定变量），Outline针对绑定变量的sql较好。
针对
使用字面值的sql的情况，须要每条sql都生成outline。 - 创建outline须要create any outline or execute_catelog_role权限 。
- 要注意从CBO的角度来看。数据库表和索引的统计信息是随着数据量的变化而不断改变的。固定的运行计划在某些时段并不一定是最优的运行计划。所以outline的使用是要依据详细情况来决定的。
- 第一次应用Outline （alter system ）这个操作是会产生Library cache pin的，需慎重。
- 10.2.0.4 outline bug 6455659
- use_stored_outlines參数重新启动后失效，须要又一次设置
- 当outline依赖的对象被删除时。outline并不会自己主动删除
- 两个基本视图：dba_outlines,dba_outline_hints
- 三个底层表：ol$、ol$hints、ol$nodes
SQL> set long 30
SQL> set long 50
SQL> select name,owner,category,used,sql_text from dba_outlines;
NAME OWNER CATEGORY USED SQL_TEXT
------------------------------ ------------------------------ ------------------------------ ------
OUTLINE_DH_TEST DBMON TEST UNUSED select * from dh_stat where id=11
SQL> select name,hint from dba_outline_hints;
NAME HINT
------------------------------ --------------------------------------------------
OUTLINE_DH_TEST FULL(@"SEL$1" "DH_STAT"@"SEL$1")
OUTLINE_DH_TEST OUTLINE_LEAF(@"SEL$1")
OUTLINE_DH_TEST ALL_ROWS
OUTLINE_DH_TEST OPT_PARAM('_optimizer_use_feedback' 'false')
OUTLINE_DH_TEST OPT_PARAM('_optimizer_adaptive_cursor_sharing' 'fa
OUTLINE_DH_TEST OPT_PARAM('_optimizer_extended_cursor_sharing_rel'
OUTLINE_DH_TEST OPT_PARAM('_bloom_pruning_enabled' 'false')
OUTLINE_DH_TEST OPT_PARAM('_gby_hash_aggregation_enabled' 'false')
OUTLINE_DH_TEST OPT_PARAM('_optimizer_extended_cursor_sharing' 'no
OUTLINE_DH_TEST OPT_PARAM('_bloom_filter_enabled' 'false')
OUTLINE_DH_TEST OPT_PARAM('_optimizer_null_aware_antijoin' 'false'
OUTLINE_DH_TEST OPT_PARAM('_optim_peek_user_binds' 'false')
OUTLINE_DH_TEST DB_VERSION('11.2.0.1')
OUTLINE_DH_TEST OPTIMIZER_FEATURES_ENABLE('11.2.0.1')
OUTLINE_DH_TEST IGNORE_OPTIM_EMBEDDED_HINTS
15 rows selected.
- 不指定outline类别是，默觉得default，并且此处创建时，不能指定为default类别（会报错）。
- 这种方法不是非常方便。由于必须将整个SQL文本作为语句的一部分，可能导致语句无法共享等问题。因此非常少使用这样的方法
- 这样的方法不能指定outline的详细名字。由系统自己主动生成，能够通过alter outline SYS_OUTLINE_14061114223605901 rename to dh_test2改动
- 不指定类别的话默觉得default，并且此处创建时，不能指定为default类别（会报错）。
- 我们使用outline固定运行计划时，一般都是选用此种方法
- 后面有一个简单演示样例，能够加深理解
只是还好这种方法也很easy。由于outline相关的hint数据都保存在outln用户下的三张表中：ol$、ol$hints、ol$nodes。能够用以下的命令来导入和导出可用的outline
| Select HINT_TEXT,USER_TABLE_NAME,JOIN_PRED,cardinality,bytes,cost from OUTLN.OL$HINTS where ol_name = 'OLXXXXX_ORIG' |
SET OL_NAME = DECODE(OL_NAME,
'OLXXXXX_MOD',
'OLXXXXX_ORIG',
'OLXXXXX_ORIG',
'OLXXXXX_MOD')
WHERE OL_NAME IN ('OLXXXXX_MOD', 'OLXXXXX_ORIG');
系统已更改。
SQL> exec DBMS_STATS.GATHER_TABLE_STATS(OWNNAME=>'dbmon',TABNAME=>'dh_stat',ESTIMATE_PERCENT=>30,METHOD_OPT=>'FOR ALL COLUMNS SIZE 1',NO_INVALIDATE=>FALSE,CASCADE=>TRUE,DEGREE => 1);
PL/SQL 过程已成功完毕。
SQL> col name format a15
SQL> col name format a30
SQL> col sql_text format a55
SQL> select /* outlinetest1 */ * from dh_stat where id=771;
ID NAME TYPE
---------- ------------------------------ ---------------
771 APPLY$_CONF_HDLR_COLUMNS_UNQ1 INDEX
SQL> select sql_text,sql_id,hash_value,child_number from v$sql a where sql_text like '%outlinetest1%' and sql_text not like '%v$sql%';
SQL_TEXT SQL_ID HASH_VALUE CHILD_NUMBER
------------------------------------------------------- ------------- ---------- ------------
select /* outlinetest1 */ * from dh_stat where id=771 053nzgm4f6rdr 3370343863 0
SQL> select * from table(dbms_xplan.display_cursor('053nzgm4f6rdr','',''));
PLAN_TABLE_OUTPUT
---------------------------------------------------------------------------------------------------------------------------------------
SQL_ID 053nzgm4f6rdr, child number 0
-------------------------------------
select /* outlinetest1 */ * from dh_stat where id=771
Plan hash value: 2780970545
---------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | | | 2 (100)| |
| 1 | TABLE ACCESS BY INDEX ROWID| DH_STAT | 1 | 38 | 2 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IND_1 | 1 | | 1 (0)| 00:00:01 |
---------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("ID"=771)
已选择19行。
SQL> exec DBMS_OUTLN.create_outline(hash_value=>3370343863,child_number => 0,category=>'TEST');
PL/SQL 过程已成功完毕。
SQL> col category format a10
SQL> select name,category,used,sql_text from dba_outlines;
NAME CATEGORY USED SQL_TEXT
------------------------------ ---------- ------ -------------------------------------------------------
SYS_OUTLINE_14061209594622403 TEST UNUSED select /* outlinetest1 */ * from dh_stat where id=771
能够看到。outline确实已经生成
SQL> select /* outlinetest1 */ * from dh_stat where id=771;
ID NAME TYPE
---------- ------------------------------ ---------------
771 APPLY$_CONF_HDLR_COLUMNS_UNQ1 INDEX
SQL> select name,category,used,sql_text from dba_outlines;
NAME CATEGORY USED SQL_TEXT
------------------------------ ---------- ------ -------------------------------------------------------
SYS_OUTLINE_14061209594622403 TEST UNUSED select /* outlinetest1 */ * from dh_stat where id=771
此处outline的USED状态没有改变，由于我们没有激活TEST类别的outline，再次申明，outline必须通过use_stored_outlines參数激活后，优化器才会使用outline！
SQL> select * from table(dbms_xplan.display_cursor('053nzgm4f6rdr','',''));
PLAN_TABLE_OUTPUT
---------------------------------------------------------------------------------------------------------------------------------------
SQL_ID 053nzgm4f6rdr, child number 0
-------------------------------------
select /* outlinetest1 */ * from dh_stat where id=771
Plan hash value: 2780970545
---------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time
|
---------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | | | 2 (100)|
|
| 1 | TABLE ACCESS BY INDEX ROWID|
DH_STAT | 1 | 38 | 2 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IND_1 | 1 | | 1
(0)| 00:00:01 |
---------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("ID"=771)
已选择19行。
以下这一步激活TEST类别的OUTLINE。也能够在系统级激活OUTLINE
SQL> alter session set use_stored_outlines=TEST;
会话已更改。
SQL> select /* outlinetest1 */ * from dh_stat where id=771;
ID NAME TYPE
---------- ------------------------------ ---------------
771 APPLY$_CONF_HDLR_COLUMNS_UNQ1 INDEX
SQL> select name,category,used,sql_text from dba_outlines;
NAME CATEGORY USED SQL_TEXT
------------------------------ ---------- ------ -------------------------------------------------------
SYS_OUTLINE_14061209594622403 TEST USED select /* outlinetest1 */ * from dh_stat where id=771
SQL> select * from table(dbms_xplan.display_cursor('053nzgm4f6rdr','',''));
PLAN_TABLE_OUTPUT
---------------------------------------------------------------------------------------------------------------------------------------
SQL_ID 053nzgm4f6rdr, child number 0
-------------------------------------
select /* outlinetest1 */ * from dh_stat where id=771
Plan hash value: 2780970545
---------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | | | 2 (100)| |
| 1 | TABLE ACCESS BY INDEX ROWID| DH_STAT | 1 | 38 | 2 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IND_1 | 1 | | 1 (0)| 00:00:01 |
---------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("ID"=771)
SQL_ID 053nzgm4f6rdr, child number 1
-------------------------------------
select /* outlinetest1 */ * from dh_stat where id=771
Plan hash value: 2780970545
---------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | | | 2 (100)| |
| 1 | TABLE ACCESS BY INDEX ROWID| DH_STAT | 1 | 38 | 2 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IND_1 | 1 | | 1 (0)| 00:00:01 |
---------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("ID"=771)
Note
-----
- outline "SYS_OUTLINE_14061209594622403" used for this statement
已选择42行。
PL/SQL 过程已成功完毕。
SQL> select name,category,used,sql_text from dba_outlines;
NAME CATEGORY USED SQL_TEXT
------------------------------ ---------- ------ -------------------------------------------------------
SYS_OUTLINE_14061209594622403 TEST UNUSED select /* outlinetest1 */ * from dh_stat where id=771
SQL> select /* outlinetest2 */ /*+ full(dh_stat) */ * from dh_stat where id=771;
ID NAME TYPE
---------- ------------------------------ ---------------
771 APPLY$_CONF_HDLR_COLUMNS_UNQ1 INDEX
SQL> select sql_text,sql_id,hash_value,child_number from v$sql a where sql_text like '%outlinetest2%' and sql_text not like '%v$sql%';
SQL_TEXT SQL_ID HASH_VALUE CHILD_NUMBER
------------------------------------------------------- ------------- ---------- ------------
select /* outlinetest2 */ /*+ full(dh_stat) */ * from d 3fcq9c8xu4a92 1000483106 0
h_stat where id=771
SQL> alter session set use_stored_outlines=true;
会话已更改。
SQL> select * from table(dbms_xplan.display_cursor('3fcq9c8xu4a92','',''));
PLAN_TABLE_OUTPUT
---------------------------------------------------------------------------------------------------------------------------------------
SQL_ID 3fcq9c8xu4a92, child number 0
-------------------------------------
select /* outlinetest2 */ /*+ full(dh_stat) */ * from dh_stat where
id=771
Plan hash value: 1845196118
-----------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
-----------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | | | 124 (100)| |
|* 1 | TABLE ACCESS FULL| DH_STAT | 1 | 38 | 124 (1)| 00:00:02 |
-----------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("ID"=771)
已选择19行。
SQL> exec DBMS_OUTLN.create_outline(hash_value=>1000483106,child_number => 0,category=>'TEST');
PL/SQL 过程已成功完毕。
SQL> select name,category,used,sql_text from dba_outlines;
NAME CATEGORY USED SQL_TEXT
------------------------------ ---------- ------ -------------------------------------------------------
SYS_OUTLINE_14061210153067004 TEST UNUSED select /* outlinetest2 */ /*+ full(dh_stat) */ * from d
h_stat where id=771
SYS_OUTLINE_14061209594622403 TEST UNUSED select /* outlinetest1 */ * from dh_stat where id=771
能够看到。我们新建的outline。确实已经成功
SQL> alter session set use_stored_outlines=TEST;
会话已更改。
SQL> select /* outlinetest1 */ * from dh_stat where id=771;
ID NAME TYPE
---------- ------------------------------ ---------------
771 APPLY$_CONF_HDLR_COLUMNS_UNQ1 INDEX
SQL> select /* outlinetest2 */ /*+ full(dh_stat) */ * from dh_stat where id=771;
ID NAME TYPE
---------- ------------------------------ ---------------
771 APPLY$_CONF_HDLR_COLUMNS_UNQ1 INDEX
SQL> select name,category,used,sql_text from dba_outlines;
NAME CATEGORY USED SQL_TEXT
------------------------------ ---------- ------ -------------------------------------------------------
SYS_OUTLINE_14061210153067004 TEST USED select /* outlinetest2 */ /*+ full(dh_stat) */ * from d
h_stat where id=771
SYS_OUTLINE_14061209594622403 TEST USED select /* outlinetest1 */ * from dh_stat where id=771
能够看到，两个outline都已经标记为已经使用过
SQL> select * from table(dbms_xplan.display_cursor('3fcq9c8xu4a92','',''));
PLAN_TABLE_OUTPUT
---------------------------------------------------------------------------------------------------------------------------------------
SQL_ID 3fcq9c8xu4a92, child number 0
-------------------------------------
select /* outlinetest2 */ /*+ full(dh_stat) */ * from dh_stat where
id=771
Plan hash value: 1845196118
-----------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time
|
-----------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | | | 124 (100)|
|
|* 1 | TABLE ACCESS FULL| DH_STAT
| 1 | 38 | 124 (1)| 00:00:02 |
-----------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("ID"=771)
Note
-----
- outline "SYS_OUTLINE_14061210153067004" used for this statement
已选择23行。
SQL> select * from table(dbms_xplan.display_cursor('053nzgm4f6rdr','',''));
PLAN_TABLE_OUTPUT
---------------------------------------------------------------------------------------------------------------------------------------
....此处为了排版，省略了一个child number 0 的运行计划！........
-------------------------------------
select /* outlinetest1 */ * from dh_stat where id=771
Plan hash value: 2780970545
---------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | | | 2 (100)| |
| 1 | TABLE ACCESS BY INDEX ROWID| DH_STAT | 1 | 38 | 2 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IND_1 | 1 | | 1 (0)| 00:00:01 |
---------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("ID"=771)
Note
-----
- outline "SYS_OUTLINE_14061209594622403" used for this statement
已选择42行。
SQL> alter session set use_stored_outlines=TRUE;
会话已更改。
SQL> UPDATE OUTLN.OL$HINTS
2 SET OL_NAME = DECODE(OL_NAME,
3 'SYS_OUTLINE_14061210153067004',
4 'SYS_OUTLINE_14061209594622403',
5 'SYS_OUTLINE_14061209594622403',
6 'SYS_OUTLINE_14061210153067004')
7 WHERE OL_NAME IN ('SYS_OUTLINE_14061210153067004', 'SYS_OUTLINE_14061209594622403');
已更新12行。
SQL> commit;
提交完毕。
SQL> col hint_text format a50
SQL> select hint#,hint_text from outln.ol$hints a where ol_name='SYS_OUTLINE_14061209594622403';
HINT# HINT_TEXT
---------- --------------------------------------------------
1 FULL(@"SEL$1" "DH_STAT"@"SEL$1")
2 OUTLINE_LEAF(@"SEL$1")
3 ALL_ROWS
4 DB_VERSION('11.2.0.1')
5 OPTIMIZER_FEATURES_ENABLE('11.2.0.1')
6 IGNORE_OPTIM_EMBEDDED_HINTS
已选择6行。
果然和我们预期的一样。outline里面的运行计划已经调换
SQL> select /* outlinetest1 */ * from dh_stat where id=771;
ID NAME TYPE
---------- ------------------------------ ---------------
771 APPLY$_CONF_HDLR_COLUMNS_UNQ1 INDEX
SQL> select * from table(dbms_xplan.display_cursor('053nzgm4f6rdr','',''));
PLAN_TABLE_OUTPUT
---------------------------------------------------------------------------------------------------------------------------------------
SQL_ID 053nzgm4f6rdr, child number 0
-------------------------------------
select /* outlinetest1 */ * from dh_stat where id=771
Plan hash value: 2780970545
---------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time
|
---------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | | | 2 (100)|
|
| 1 | TABLE ACCESS BY INDEX ROWID|
DH_STAT | 1 | 38 | 2 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IND_1 | 1 | | 1
(0)| 00:00:01 |
---------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("ID"=771)
SQL_ID 053nzgm4f6rdr, child number 1
-------------------------------------
select /* outlinetest1 */ * from dh_stat where id=771
Plan hash value: 2780970545
---------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time
|
---------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | | | 2 (100)|
|
| 1 | TABLE ACCESS BY INDEX ROWID|
DH_STAT | 1 | 38 | 2 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IND_1 | 1 | | 1
(0)| 00:00:01 |
---------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("ID"=771)
Note
-----
- outline "SYS_OUTLINE_14061209594622403" used for this statement
SQL_ID 053nzgm4f6rdr, child number 2
-------------------------------------
select /* outlinetest1 */ * from dh_stat where id=771
Plan hash value: 2780970545
---------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time
|
---------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | | | 2 (100)|
|
| 1 | TABLE ACCESS BY INDEX ROWID|
DH_STAT | 1 | 38 | 2 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IND_1 | 1 | | 1
(0)| 00:00:01 |
---------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("ID"=771)
已选择61行。
激活outline
SQL> alter session set use_stored_outlines=TEST;
会话已更改。
SQL> exec dbms_outln.clear_used(name=>'SYS_OUTLINE_14061209594622403');
PL/SQL 过程已成功完毕。
SQL> select name,category,used,sql_text from dba_outlines;
NAME CATEGORY USED SQL_TEXT
------------------------------ ---------- ------ -------------------------------------------------------
SYS_OUTLINE_14061210153067004 TEST USED select /* outlinetest2 */ /*+ full(dh_stat) */ * from d
h_stat where id=771
SYS_OUTLINE_14061209594622403 TEST UNUSED select /* outlinetest1 */ * from dh_stat where id=771
SQL> select /* outlinetest1 */ * from dh_stat where id=771;
ID NAME TYPE
---------- ------------------------------ ---------------
771 APPLY$_CONF_HDLR_COLUMNS_UNQ1 INDEX
SQL> select name,category,used,sql_text from dba_outlines;
NAME CATEGORY USED SQL_TEXT
------------------------------ ---------- ------ -------------------------------------------------------
SYS_OUTLINE_14061210153067004 TEST USED select /* outlinetest2 */ /*+ full(dh_stat) */ * from d
h_stat where id=771
SYS_OUTLINE_14061209594622403 TEST USED select /* outlinetest1 */ * from dh_stat where id=771
SQL> select * from table(dbms_xplan.display_cursor('053nzgm4f6rdr','',''));
PLAN_TABLE_OUTPUT
---------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------
SQL_ID 053nzgm4f6rdr, child number 0
-------------------------------------
select /* outlinetest1 */ * from dh_stat where id=771
Plan hash value: 2780970545
---------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time
|
---------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | | | 2 (100)|
|
| 1 | TABLE ACCESS BY INDEX ROWID|
DH_STAT | 1 | 38 | 2 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IND_1 | 1 | | 1
(0)| 00:00:01 |
---------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("ID"=771)
SQL_ID 053nzgm4f6rdr, child number 1
-------------------------------------
select /* outlinetest1 */ * from dh_stat where id=771
Plan hash value: 2780970545
---------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time
|
---------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | | | 2 (100)|
|
| 1 | TABLE ACCESS BY INDEX ROWID|
DH_STAT | 1 | 38 | 2 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IND_1 | 1 | | 1
(0)| 00:00:01 |
---------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("ID"=771)
Note
-----
- outline "SYS_OUTLINE_14061209594622403" used for this statement
SQL_ID 053nzgm4f6rdr, child number 2
-------------------------------------
select /* outlinetest1 */ * from dh_stat where id=771
Plan hash value: 2780970545
---------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time
|
---------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | | | 2 (100)|
|
| 1 | TABLE ACCESS BY INDEX ROWID|
DH_STAT | 1 | 38 | 2 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IND_1 | 1 | | 1
(0)| 00:00:01 |
---------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("ID"=771)
SQL_ID 053nzgm4f6rdr, child number 3
-------------------------------------
select /* outlinetest1 */ * from dh_stat where id=771
Plan hash value: 2780970545
---------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time
|
---------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | | | 2 (100)|
|
| 1 | TABLE ACCESS BY INDEX ROWID|
DH_STAT | 1 | 38 | 2 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IND_1 | 1 | | 1
(0)| 00:00:01 |
---------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("ID"=771)
Note
-----
- outline "SYS_OUTLINE_14061209594622403" used for this statement
已选择84行。
想要得到我们预期，通过全表扫描来实现，我在測试中是通过以下的方法实现