原 Oracle固定执行计划的方法--outline、SQL Profile和SPM（绑定执行计划）
Tags： Oracle原创执行计划绑定执行计划outlineSPMSQL Profile
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目录
SQL概要（SQL Profile）
SQL Profile就是为某条SQL语句提供除了系统统计信息、对象（表和索引等）统计信息之外的其它信息，比如运行环境、额外的更准确的统计信息，以帮助优化器为SQL语句选择更适合的执行计划。SQL Profile可以说是Outline的进化。Outline能够实现的功能SQL Profile也完全能够实现，而SQL Profile具有Outline不具备的优化，最重要的有两点：①SQL Profile更容易生成、更改和控制。**②SQL Profile在对SQL语句的支持上做得更好，也就是适用范围更广。**
对于sqlprof_attr部分的数据可以使用脚本coe_xfr_sql_profile.sql脚本生成。
使用SQL Profile的两个目的：①锁定或者说是稳定执行计划。②在不能修改应用中的SQL的情况下使SQL语句按指定的执行计划运行。
SQL Profile最大的优点是在不修改SQL语句和会话执行环境的情况下去优化SQL的执行效率，适合无法在应用程序中修改SQL时。
SQL Profile对以下类型语句有效：
SELECT语句；
UPDATE语句；
INSERT语句（仅当使用SELECT子句时有效）；
DELETE语句；
CREATE语句（仅当使用SELECT子句时有效）；
MERGE语句（仅当作UPDATE和INSERT操作时有效）。
另外，使用SQL Profile还必须有CREATE ANY SQL PROFILE、DROP ANY SQL PROFILE和ALTER ANY SQL PROFILE等系统权限。
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 | drop table TB_LHR_20240410; Create table TB_LHR_20240410 as select * from dba_objects; create index IND_TB_LHR_ID2 on TB_LHR_20240410(object_id); explain plan for select * from TB_LHR_20240410 where object_id= :a; select * from table(dbms_xplan.display(null,null,'outline')); INDEX_RS_ASC(@"SEL$1" "TB_LHR_20240410"@"SEL$1" ("TB_LHR_20240410"."OBJECT_ID")) explain plan for select /*+ full(TB_LHR_20240410) */* from TB_LHR_20240410 where object_id= :a; select * from table(dbms_xplan.display(null,null,'outline')); FULL(@"SEL$1" "TB_LHR_20240410"@"SEL$1") select * from table(DBMS_XPLAN.DISPLAY_CURSOR('cn9fqrd5w0841',0,'outline')); declare v_hints sys.sqlprof_attr; begin v_hints := sys.sqlprof_attr('FULL(@"SEL$1" "TB_LHR_20240410"@"SEL$1")'); ----------从上面Outline Data部分获取到的HINT dbms_sqltune.import_sql_profile('select * from TB_LHR_20240410 where object_id= :a', ----------SQL语句部分 v_hints, 'TB_LHR_20240410_5', --------PROFILE 的名字 force_match => false); end; / explain plan for select * from TB_LHR_20240410 where object_id= :a; select * from table(dbms_xplan.display); explain plan for select * from TB_LHR_20240410 where object_id= :a; select * from table(dbms_xplan.display); var a number; exec :a :=100; select * from TB_LHR_20240410 where object_id= :a; select * from TB_LHR_20240410 where object_id= :a; select * from TB_LHR_20240410 WHERE object_id= :a; select a.sql_profile,a.executions,a.sql_text from v$sql a where a.sql_text like '%TB_LHR_20240410%' ; select a.version_count,a.executions,a.sql_profile,a.sql_text from v$sqlarea a where a.sql_text like '%TB_LHR_20240410%' ; SELECT b.name,d.sql_text, extractvalue(value(h),'.') as hints FROM dba_sql_profiles d,SYS.SQLOBJ$DATA A, SYS.SQLOBJ$ B, TABLE(XMLSEQUENCE(EXTRACT(XMLTYPE(A.COMP_DATA), '/outline_data/hint'))) h where a.signature = b.signature and a.category = b.category and a.obj_type = b.obj_type and a.plan_id = b.plan_id and a.signature=d.signature and D.name = 'TB_LHR_20240410'; 测试完后，可以通过exec dbms_sqltune.drop_sql_profile(name =>'TB_LHR_20240410_5' );删除这个Sql Profile。 |
有两种生成SQL Profile的方法，分别是手动和采用STA来生成。
SQL Profile使用示例--手工创建SQL Profile
创建测试表，根据DBA_OBJECTS创建，OBJECT_ID上有索引
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | LHR@dlhr> select * from v$version; BANNER -------------------------------------------------------------------------------- Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production PL/SQL Release 11.2.0.4.0 - Production CORE 11.2.0.4.0 Production TNS for IBM/AIX RISC System/6000: Version 11.2.0.4.0 - Production NLSRTL Version 11.2.0.4.0 - Production LHR@dlhr> Create table TB_LHR_20160525 as select * from dba_objects; Table created. LHR@dlhr> create index IND_TB_LHR_ID on TB_LHR_20160525(object_id); Index created. |
查看SQL默认执行计划，走了索引，通过指定Outline可以获取到系统为我们生成的hint
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 | LHR@dlhr> explain plan for select * from TB_LHR_20160525 where object_id= :a; Explained. LHR@dlhr> select * from table(dbms_xplan.display(null,null,'outline')); PLAN_TABLE_OUTPUT -------------------------------------------------------------------------------------------------------- Plan hash value: 4254050152 ----------------------------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ----------------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 886 | 179K| 7 (0)| 00:00:01 | | 1 | TABLE ACCESS BY INDEX ROWID| TB_LHR_20160525 | 886 | 179K| 7 (0)| 00:00:01 | |* 2 | INDEX RANGE SCAN | IND_TB_LHR_ID | 354 | | 1 (0)| 00:00:01 | ----------------------------------------------------------------------------------------------- Outline Data ------------- /*+ BEGIN_OUTLINE_DATA INDEX_RS_ASC(@"SEL$1" "TB_LHR_20160525"@"SEL$1" ("TB_LHR_20160525"."OBJECT_ID")) 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("OBJECT_ID"=TO_NUMBER(:A)) Note ----- - dynamic sampling used for this statement (level=2) 32 rows selected. |
如果我们想让它走全表扫描，首先获取全表扫描HINT
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 | LHR@dlhr> explain plan for select /*+ full(TB_LHR_20160525) */* from TB_LHR_20160525 where object_id= :a; Explained. LHR@dlhr> select * from table(dbms_xplan.display(null,null,'outline')); PLAN_TABLE_OUTPUT ----------------------------------------------------------------------------------------- Plan hash value: 345881005 ------------------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 886 | 179K| 352 (2)| 00:00:05 | |* 1 | TABLE ACCESS FULL| TB_LHR_20160525 | 886 | 179K| 352 (2)| 00:00:05 | ------------------------------------------------------------------------------------- Outline Data ------------- /*+ BEGIN_OUTLINE_DATA FULL(@"SEL$1" "TB_LHR_20160525"@"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("OBJECT_ID"=TO_NUMBER(:A)) Note ----- - dynamic sampling used for this statement (level=2) 31 rows selected. |
可以看到全表扫描的Hint已经为我们生成了，我们选取必要的hint就OK了，其它的可以不要，使用SQL Profile
1 2 3 4 5 6 7 8 9 10 11 12 13 | LHR@dlhr> declare 2 v_hints sys.sqlprof_attr; 3 begin 4 v_hints := sys.sqlprof_attr('FULL(@"SEL$1" "TB_LHR_20160525"@"SEL$1")'); ----------从上面Outline Data部分获取到的HINT 5 dbms_sqltune.import_sql_profile('select * from TB_LHR_20160525 where object_id= :a', ----------SQL语句部分 6 v_hints, 7 'TB_LHR_20160525', --------PROFILE 的名字 8 force_match => true); 9 end; 10 / PL/SQL procedure successfully completed. |
查看是否生效，已经生效了：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 | LHR@dlhr> explain plan for select * from TB_LHR_20160525 where object_id= :a; Explained. LHR@dlhr> select * from table(dbms_xplan.display); PLAN_TABLE_OUTPUT ---------------------------------------------------------------------------------------------------------------------------- Plan hash value: 345881005 ------------------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 886 | 179K| 352 (2)| 00:00:05 | |* 1 | TABLE ACCESS FULL| TB_LHR_20160525 | 886 | 179K| 352 (2)| 00:00:05 | ------------------------------------------------------------------------------------- Predicate Information (identified by operation id): --------------------------------------------------- 1 - filter("OBJECT_ID"=TO_NUMBER(:A)) Note ----- - dynamic sampling used for this statement (level=2) - SQL profile "TB_LHR_20160525" used for this statement 18 rows selected. LHR@dlhr> SELECT b.name,d.sql_text, extractvalue(value(h),'.') as hints 2 FROM dba_sql_profiles d,SYS.SQLOBJ$DATA A, 3 SYS.SQLOBJ$ B, 4 TABLE(XMLSEQUENCE(EXTRACT(XMLTYPE(A.COMP_DATA), 5 '/outline_data/hint'))) h 6 where a.signature = b.signature 7 and a.category = b.category 8 and a.obj_type = b.obj_type 9 and a.plan_id = b.plan_id 10 and a.signature=d.signature 11 and D.name = 'TB_LHR_20160525'; NAME SQL_TEXT HINTS ------------------------------ -------------------------------------------------------------------------------- ------------------------------------------------------- TB_LHR_20160525 select * from TB_LHR_20160525 where object_id= :a FULL(@"SEL$1" "TB_LHR_20160525"@"SEL$1") |
①、 coe_xfr_sql_profile.sql
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