Oracle ---- 固定执行计划之SqlPatch
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今天我们来做一个使用SqlPatch固定执行计划的TEST.
1.做TEST用TABLE.
create table tab2(c1 number, c2 number, c3 varchar2(10));
declare
a number;
begin
a := 1;
for i in 1 .. 50 loop
for j in 1 .. 100 loop
insert into tab2 values(a,j,\'a\');
commit;
a := a+1;
end loop;
end loop;
end;
/
create index ind2_2 on tab2(c2);
2.观察SQLPLAN
SQL> conn test/test
SQL> explain plan for select * from tab2 where c2=1;
解析されました。
SQL> select * from table (dbms_xplan.display(format=>\'advanced\'));
PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------
Plan hash value: 2156729920
--------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 50 | 450 | 5 (0)| 00:00:01 |
|* 1 | TABLE ACCESS FULL| TAB2 | 50 | 450 | 5 (0)| 00:00:01 |
--------------------------------------------------------------------------
Query Block Name / Object Alias (identified by operation id):
-------------------------------------------------------------
1 - SEL$1 / TAB2@SEL$1
Outline Data
-------------
/*+
BEGIN_OUTLINE_DATA
FULL(@"SEL$1" "TAB2"@"SEL$1")
OUTLINE_LEAF(@"SEL$1")
ALL_ROWS
DB_VERSION(\'11.2.0.4\')
OPTIMIZER_FEATURES_ENABLE(\'11.2.0.4\')
IGNORE_OPTIM_EMBEDDED_HINTS
END_OUTLINE_DATA
*/
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("C2"=1)
Column Projection Information (identified by operation id):
-----------------------------------------------------------
1 - "TAB2"."C1"[NUMBER,22], "C2"[NUMBER,22], "TAB2"."C3"[VARCHAR2,10]
37行が選択されました。
3.通过Hint做成使用Index Scan的SQLPLAN
SQL> explain plan for select /*+ index(tab2 ind2_2) */ * from tab2 where c2=1;
解析されました。
SQL> select * from table (dbms_xplan.display(format=>\'advanced\'));
PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------
Plan hash value: 3201770281
--------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 50 | 450 | 11 (0)| 00:00:01 |
| 1 | TABLE ACCESS BY INDEX ROWID| TAB2 | 50 | 450 | 11 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IND2_2 | 50 | | 1 (0)| 00:00:01 |
--------------------------------------------------------------------------------------
Query Block Name / Object Alias (identified by operation id):
-------------------------------------------------------------
1 - SEL$1 / TAB2@SEL$1
2 - SEL$1 / TAB2@SEL$1
Outline Data
-------------
/*+
BEGIN_OUTLINE_DATA
INDEX_RS_ASC(@"SEL$1" "TAB2"@"SEL$1" ("TAB2"."C2"))
OUTLINE_LEAF(@"SEL$1")
ALL_ROWS
DB_VERSION(\'11.2.0.4\')
OPTIMIZER_FEATURES_ENABLE(\'11.2.0.4\')
IGNORE_OPTIM_EMBEDDED_HINTS
END_OUTLINE_DATA
*/
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("C2"=1)
Column Projection Information (identified by operation id):
-----------------------------------------------------------
1 - "TAB2"."C1"[NUMBER,22], "C2"[NUMBER,22], "TAB2"."C3"[VARCHAR2,10]
2 - "TAB2".ROWID[ROWID,10], "C2"[NUMBER,22]
40行が選択されました。
4.把Hint“INDEX_RS_ASC(@"SEL$1" "TAB2"@"SEL$1" ("TAB2"."C2"))”作成SqlPatch。
SQL> connect / as sysdba
SQL> begin
dbms_sqldiag_internal.i_create_patch (
sql_text => \'select * from tab2 where c2=1\',
hint_text => \'INDEX_RS_ASC(@"SEL$1" "TAB2"@"SEL$1" ("TAB2"."C2"))\',
name => \'test patch\'
);
end;
/ 2 3 4 5 6 7 8
PL/SQLプロシージャが正常に完了しました。
5.看看结果。
SQL> conn test/test
SQL> set lin 120 pages 999
SQL> set autot on explain
SQL> select * from tab2 where c2=1;
C1 C2 C3
---------- ---------- ------------------------------
601 1 a
... ...
4101 1 a
50行が選択されました。
実行計画
----------------------------------------------------------
Plan hash value: 3201770281
--------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 50 | 450 | 11 (0)| 00:00:01 |
| 1 | TABLE ACCESS BY INDEX ROWID| TAB2 | 50 | 450 | 11 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IND2_2 | 50 | | 1 (0)| 00:00:01 |
--------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("C2"=1)
Note
-----
- SQL patch "test patch" used for this statement
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