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【DB笔试面试608】在Oracle中,如何使用STA来生成SQL Profile?

2021-04-15 22:57:38  阅读:244  来源: 互联网

标签:Profile 01 STA dlhr 20160525 LHR SQL TB


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题目 部分

在Oracle中,如何使用STA来生成SQL Profile?


     

答案部分


利用STA对语句进行优化后,STA会对语句进行分析,采用最优的优化策略,并给出优化后的查询计划。可以按照STA给出的建议重写语句。但是,有些情况下,你可能无法重写语句(比如在生产环境中,SQL语句又在一个包中)。这个时候就可以利用Sql Profile,将优化策略存储在Profile中,Oracle在构建这条语句的查询计划时,就不会使用已有相关统计数据,而使用Profile的策略,生成新的查询计划。

第一步:给用户赋权限

 1[ZHLHRSPMDB2:oracle]:/oracle>sqlplus / as sysdba  2  3SQL*Plus: Release 11.2.0.4.0 Production on Wed May 25 16:47:29 2016  4  5Copyright (c) 1982, 2013, Oracle.  All rights reserved.  6  7  8Connected to:  9Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production 10With the Partitioning, Real Application Clusters, OLAP, Data Mining 11and Real Application Testing options 12 13SYS@dlhr>  14SYS@dlhr>  15SYS@dlhr>  16SYS@dlhr> GRANT CREATE ANY SQL PROFILE TO LHR; 17 18Grant succeeded. 19 20SYS@dlhr> GRANT DROP ANY SQL PROFILE TO LHR; 21 22Grant succeeded. 23 24SYS@dlhr> GRANT ALTER ANY SQL PROFILE TO LHR; 25 26Grant succeeded. 27 28SYS@dlhr> conn lhr/lhr 29Connected. 30LHR@dlhr>  31LHR@dlhr> select * from v$version; 32 33BANNER 34-------------------------------------------------------------------------------- 35Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production 36PL/SQL Release 11.2.0.4.0 - Production 37CORE    11.2.0.4.0      Production 38TNS for IBM/AIX RISC System/6000: Version 11.2.0.4.0 - Production 39NLSRTL Version 11.2.0.4.0 - Production 40 41LHR@dlhr> create table lhr.TB_LHR_20160525_01 as select * from dba_objects;  42 43Table created. 44 45LHR@dlhr> create index lhr.TB_LHR_20160525_01_idx on TB_LHR_20160525_01(object_id);    46 47Index created. 48 49LHR@dlhr> exec dbms_stats.gather_table_stats('lhr','TB_LHR_20160525_01',cascade=>true,degree=>4);    50 51PL/SQL procedure successfully completed. 52 53LHR@dlhr> set autot on 54LHR@dlhr> select /*+no_index(TB_LHR_20160525_01 TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_LHR_20160525_01 where object_id = 100 ; 55 56  COUNT(*) 57---------- 58         1 59 60 61Execution Plan 62---------------------------------------------------------- 63Plan hash value: 3612989399 64 65----------------------------------------------------------------------------------------- 66| Id  | Operation          | Name               | Rows  | Bytes | Cost (%CPU)| Time     | 67----------------------------------------------------------------------------------------- 68|   0 | SELECT STATEMENT   |                    |     1 |     5 |   351   (2)| 00:00:05 | 69|   1 |  SORT AGGREGATE    |                    |     1 |     5 |            |          | 70|*  2 |   TABLE ACCESS FULL| TB_LHR_20160525_01 |     1 |     5 |   351   (2)| 00:00:05 | 71----------------------------------------------------------------------------------------- 72 73Predicate Information (identified by operation id): 74--------------------------------------------------- 75 76   2 - filter("OBJECT_ID"=100) 77 78 79Statistics 80---------------------------------------------------------- 81          1  recursive calls 82          0  db block gets 83       1249  consistent gets 84          0  physical reads 85          0  redo size 86        526  bytes sent via SQL*Net to client 87        520  bytes received via SQL*Net from client 88          2  SQL*Net roundtrips to/from client 89          0  sorts (memory) 90          0  sorts (disk) 91          1  rows processed 92LHR@dlhr> set autot off 93LHR@dlhr> SELECT v.SQL_ID, v.SQL_TEXT FROM v$sql v WHERE v.SQL_TEXT like '%no_index(TB_LHR_20160525_01%' and v.SQL_TEXT not like '%v$sql%' ; 94 95SQL_ID 96------------- 97SQL_TEXT 98------------------------------------------------------------------------------------------------------------------------------------ 997jt1btjkcczb8100select /*+no_index(TB_LHR_20160525_01 TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_LHR_20160525_01 where object_id = 1001011027suktf0w95cry103EXPLAIN PLAN SET STATEMENT_ID='PLUS150249' FOR select /*+no_index(TB_LHR_20160525_01 TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_L104HR_20160525_01 where object_id = 100
 2
 3SQL*Plus: Release 11.2.0.4.0 Production on Wed May 25 16:47:29 2016
 4
 5Copyright (c) 1982, 2013, Oracle.  All rights reserved.
 6
 7
 8Connected to:
 9Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
10With the Partitioning, Real Application Clusters, OLAP, Data Mining
11and Real Application Testing options
12
13SYS@dlhr> 
14SYS@dlhr> 
15SYS@dlhr> 
16SYS@dlhr> GRANT CREATE ANY SQL PROFILE TO LHR;
17
18Grant succeeded.
19
20SYS@dlhr> GRANT DROP ANY SQL PROFILE TO LHR;
21
22Grant succeeded.
23
24SYS@dlhr> GRANT ALTER ANY SQL PROFILE TO LHR;
25
26Grant succeeded.
27
28SYS@dlhr> conn lhr/lhr
29Connected.
30LHR@dlhr> 
31LHR@dlhr> select * from v$version;
32
33BANNER
34--------------------------------------------------------------------------------
35Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
36PL/SQL Release 11.2.0.4.0 - Production
37CORE    11.2.0.4.0      Production
38TNS for IBM/AIX RISC System/6000: Version 11.2.0.4.0 - Production
39NLSRTL Version 11.2.0.4.0 - Production
40
41LHR@dlhr> create table lhr.TB_LHR_20160525_01 as select * from dba_objects; 
42
43Table created.
44
45LHR@dlhr> create index lhr.TB_LHR_20160525_01_idx on TB_LHR_20160525_01(object_id);   
46
47Index created.
48
49LHR@dlhr> exec dbms_stats.gather_table_stats('lhr','TB_LHR_20160525_01',cascade=>true,degree=>4);   
50
51PL/SQL procedure successfully completed.
52
53LHR@dlhr> set autot on
54LHR@dlhr> select /*+no_index(TB_LHR_20160525_01 TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_LHR_20160525_01 where object_id = 100 ;
55
56  COUNT(*)
57----------
58         1
59
60
61Execution Plan
62----------------------------------------------------------
63Plan hash value: 3612989399
64
65-----------------------------------------------------------------------------------------
66| Id  | Operation          | Name               | Rows  | Bytes | Cost (%CPU)| Time     |
67-----------------------------------------------------------------------------------------
68|   0 | SELECT STATEMENT   |                    |     1 |     5 |   351   (2)| 00:00:05 |
69|   1 |  SORT AGGREGATE    |                    |     1 |     5 |            |          |
70|*  2 |   TABLE ACCESS FULL| TB_LHR_20160525_01 |     1 |     5 |   351   (2)| 00:00:05 |
71-----------------------------------------------------------------------------------------
72
73Predicate Information (identified by operation id):
74---------------------------------------------------
75
76   2 - filter("OBJECT_ID"=100)
77
78
79Statistics
80----------------------------------------------------------
81          1  recursive calls
82          0  db block gets
83       1249  consistent gets
84          0  physical reads
85          0  redo size
86        526  bytes sent via SQL*Net to client
87        520  bytes received via SQL*Net from client
88          2  SQL*Net roundtrips to/from client
89          0  sorts (memory)
90          0  sorts (disk)
91          1  rows processed
92LHR@dlhr> set autot off
93LHR@dlhr> SELECT v.SQL_ID, v.SQL_TEXT FROM v$sql v WHERE v.SQL_TEXT like '%no_index(TB_LHR_20160525_01%' and v.SQL_TEXT not like '%v$sql%' ;
94
95SQL_ID
96-------------
97SQL_TEXT
98------------------------------------------------------------------------------------------------------------------------------------
997jt1btjkcczb8
100select /*+no_index(TB_LHR_20160525_01 TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_LHR_20160525_01 where object_id = 100
101
1027suktf0w95cry
103EXPLAIN PLAN SET STATEMENT_ID='PLUS150249' FOR select /*+no_index(TB_LHR_20160525_01 TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_L
104HR_20160525_01 where object_id = 100

第二步:创建、执行优化任务


1LHR@dlhr> DECLARE 2  2      my_task_name VARCHAR2(30); 3  3      my_sqltext       CLOB; 4  4  BEGIN 5  5      my_sqltext := 'select /*+no_index(TB_LHR_20160525_01 TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_LHR_20160525_01 where object_id = 100'; 6  6      my_task_name := DBMS_SQLTUNE.CREATE_TUNING_TASK( 7  7                              sql_text          => my_sqltext, 8  8                              user_name       => 'LHR', 9  9                              scope           => 'COMPREHENSIVE',10 10                              time_limit    => 60,11 11                              task_name       => 'sql_profile_test',12 12                              description => 'Task to tune a query on a specified table');13 13      DBMS_SQLTUNE.EXECUTE_TUNING_TASK( task_name => 'sql_profile_test');14 14  END;15 15  /1617PL/SQL procedure successfully completed.DECLARE
2  2      my_task_name VARCHAR2(30);
3  3      my_sqltext       CLOB;
4  4  BEGIN
5  5      my_sqltext := 'select /*+no_index(TB_LHR_20160525_01 TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_LHR_20160525_01 where object_id = 100';
6  6      my_task_name := DBMS_SQLTUNE.CREATE_TUNING_TASK(
7  7                              sql_text          => my_sqltext,
8  8                              user_name       => 'LHR',
9  9                              scope           => 'COMPREHENSIVE',
10 10                              time_limit    => 60,
11 11                              task_name       => 'sql_profile_test',
12 12                              description => 'Task to tune a query on a specified table');
13 13      DBMS_SQLTUNE.EXECUTE_TUNING_TASK( task_name => 'sql_profile_test');
14 14  END;
15 15  /
16
17PL/SQL procedure successfully completed.

或者也可以使用sqlid来生成优化任务,如下:


1LHR@dlhr> DECLARE 2  2    a_tuning_task VARCHAR2(30); 3  3  BEGIN 4  4    a_tuning_task := dbms_sqltune.create_tuning_task(sql_id    => '7jt1btjkcczb8', 5  5                                                     task_name => 'sql_profile_test_SQLID'); 6  6    dbms_sqltune.execute_tuning_task(a_tuning_task); 7  7  END; 8  8  / 910PL/SQL procedure successfully completed.DECLARE
2  2    a_tuning_task VARCHAR2(30);
3  3  BEGIN
4  4    a_tuning_task := dbms_sqltune.create_tuning_task(sql_id    => '7jt1btjkcczb8',
5  5                                                     task_name => 'sql_profile_test_SQLID');
6  6    dbms_sqltune.execute_tuning_task(a_tuning_task);
7  7  END;
8  8  /
9
10PL/SQL procedure successfully completed.




第三步:查看优化建议



 1LHR@dlhr> set autot off  2LHR@dlhr> set long 10000  3LHR@dlhr> set longchunksize 1000  4LHR@dlhr> set linesize 100  5LHR@dlhr> SELECT DBMS_SQLTUNE.REPORT_TUNING_TASK( 'sql_profile_test') from DUAL;  6  7DBMS_SQLTUNE.REPORT_TUNING_TASK('SQL_PROFILE_TEST')  8----------------------------------------------------------------------------------------------------  9GENERAL INFORMATION SECTION 10------------------------------------------------------------------------------- 11Tuning Task Name   : sql_profile_test 12Tuning Task Owner  : LHR 13Workload Type      : Single SQL Statement 14Scope              : COMPREHENSIVE 15Time Limit(seconds): 60 16Completion Status  : COMPLETED 17Started at         : 05/25/2016 16:58:31 18Completed at       : 05/25/2016 16:58:32 19 20------------------------------------------------------------------------------- 21Schema Name: LHR 22SQL ID     : 9kzm8scz6t92z 23SQL Text   : select /*+no_index(TB_LHR_20160525_01 24             TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_LHR_20160525_01 25             where object_id = 100 26 27------------------------------------------------------------------------------- 28FINDINGS SECTION (1 finding) 29------------------------------------------------------------------------------- 30 311- SQL Profile Finding (see explain plans section below) 32-------------------------------------------------------- 33  A potentially better execution plan was found for this statement. 34 35  Recommendation (estimated benefit: 99.83%) 36  ------------------------------------------ 37  - Consider accepting the recommended SQL profile. 38    execute dbms_sqltune.accept_sql_profile(task_name => 'sql_profile_test', 39            task_owner => 'LHR', replace => TRUE); 40 41  Validation results 42  ------------------ 43  The SQL profile was tested by executing both its plan and the original plan 44  and measuring their respective execution statistics. A plan may have been 45  only partially executed if the other could be run to completion in less time. 46 47                           Original Plan  With SQL Profile  % Improved 48                           -------------  ----------------  ---------- 49  Completion Status:            COMPLETE          COMPLETE 50  Elapsed Time (s):             .006278            .00004      99.36 % 51  CPU Time (s):                 .003397           .000021      99.38 % 52  User I/O Time (s):                  0                 0 53  Buffer Gets:                     1249                 2      99.83 % 54  Physical Read Requests:             0                 0 55  Physical Write Requests:            0                 0 56 57DBMS_SQLTUNE.REPORT_TUNING_TASK('SQL_PROFILE_TEST') 58---------------------------------------------------------------------------------------------------- 59  Physical Read Bytes:                0                 0 60  Physical Write Bytes:               0                 0 61  Rows Processed:                     1                 1 62  Fetches:                            1                 1 63  Executions:                         1                 1 64 65  Notes 66  ----- 67  1. Statistics for the original plan were averaged over 10 executions. 68  2. Statistics for the SQL profile plan were averaged over 10 executions. 69 70------------------------------------------------------------------------------- 71EXPLAIN PLANS SECTION 72------------------------------------------------------------------------------- 73 741- Original With Adjusted Cost 75------------------------------ 76Plan hash value: 3612989399 77 78----------------------------------------------------------------------------------------- 79| Id  | Operation          | Name               | Rows  | Bytes | Cost (%CPU)| Time     | 80----------------------------------------------------------------------------------------- 81|   0 | SELECT STATEMENT   |                    |     1 |     5 |   351   (2)| 00:00:05 | 82|   1 |  SORT AGGREGATE    |                    |     1 |     5 |            |          | 83|*  2 |   TABLE ACCESS FULL| TB_LHR_20160525_01 |     1 |     5 |   351   (2)| 00:00:05 | 84----------------------------------------------------------------------------------------- 85 86Predicate Information (identified by operation id): 87--------------------------------------------------- 88 89   2 - filter("OBJECT_ID"=100) 90 912- Using SQL Profile 92-------------------- 93Plan hash value: 661515879 94 95-------------------------------------------------------------------------------------------- 96| Id  | Operation         | Name                   | Rows  | Bytes | Cost (%CPU)| Time     | 97-------------------------------------------------------------------------------------------- 98|   0 | SELECT STATEMENT  |                        |     1 |     5 |     1   (0)| 00:00:01 | 99|   1 |  SORT AGGREGATE   |                        |     1 |     5 |            |          |100|*  2 |   INDEX RANGE SCAN| TB_LHR_20160525_01_IDX |     1 |     5 |     1   (0)| 00:00:01 |101--------------------------------------------------------------------------------------------102103Predicate Information (identified by operation id):104---------------------------------------------------105106107DBMS_SQLTUNE.REPORT_TUNING_TASK('SQL_PROFILE_TEST')108----------------------------------------------------------------------------------------------------109   2 - access("OBJECT_ID"=100)110111-------------------------------------------------------------------------------set autot off
 2LHR@dlhr> set long 10000
 3LHR@dlhr> set longchunksize 1000
 4LHR@dlhr> set linesize 100
 5LHR@dlhr> SELECT DBMS_SQLTUNE.REPORT_TUNING_TASK( 'sql_profile_test') from DUAL;
 6
 7DBMS_SQLTUNE.REPORT_TUNING_TASK('SQL_PROFILE_TEST')
 8----------------------------------------------------------------------------------------------------
 9GENERAL INFORMATION SECTION
10-------------------------------------------------------------------------------
11Tuning Task Name   : sql_profile_test
12Tuning Task Owner  : LHR
13Workload Type      : Single SQL Statement
14Scope              : COMPREHENSIVE
15Time Limit(seconds): 60
16Completion Status  : COMPLETED
17Started at         : 05/25/2016 16:58:31
18Completed at       : 05/25/2016 16:58:32
19
20-------------------------------------------------------------------------------
21Schema Name: LHR
22SQL ID     : 9kzm8scz6t92z
23SQL Text   : select /*+no_index(TB_LHR_20160525_01
24             TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_LHR_20160525_01
25             where object_id = 100
26
27-------------------------------------------------------------------------------
28FINDINGS SECTION (1 finding)
29-------------------------------------------------------------------------------
30
311- SQL Profile Finding (see explain plans section below)
32--------------------------------------------------------
33  A potentially better execution plan was found for this statement.
34
35  Recommendation (estimated benefit: 99.83%)
36  ------------------------------------------
37  - Consider accepting the recommended SQL profile.
38    execute dbms_sqltune.accept_sql_profile(task_name => 'sql_profile_test',
39            task_owner => 'LHR', replace => TRUE);
40
41  Validation results
42  ------------------
43  The SQL profile was tested by executing both its plan and the original plan
44  and measuring their respective execution statistics. A plan may have been
45  only partially executed if the other could be run to completion in less time.
46
47                           Original Plan  With SQL Profile  % Improved
48                           -------------  ----------------  ----------
49  Completion Status:            COMPLETE          COMPLETE
50  Elapsed Time (s):             .006278            .00004      99.36 %
51  CPU Time (s):                 .003397           .000021      99.38 %
52  User I/O Time (s):                  0                 0
53  Buffer Gets:                     1249                 2      99.83 %
54  Physical Read Requests:             0                 0
55  Physical Write Requests:            0                 0
56
57DBMS_SQLTUNE.REPORT_TUNING_TASK('SQL_PROFILE_TEST')
58----------------------------------------------------------------------------------------------------
59  Physical Read Bytes:                0                 0
60  Physical Write Bytes:               0                 0
61  Rows Processed:                     1                 1
62  Fetches:                            1                 1
63  Executions:                         1                 1
64
65  Notes
66  -----
67  1. Statistics for the original plan were averaged over 10 executions.
68  2. Statistics for the SQL profile plan were averaged over 10 executions.
69
70-------------------------------------------------------------------------------
71EXPLAIN PLANS SECTION
72-------------------------------------------------------------------------------
73
741- Original With Adjusted Cost
75------------------------------
76Plan hash value: 3612989399
77
78-----------------------------------------------------------------------------------------
79| Id  | Operation          | Name               | Rows  | Bytes | Cost (%CPU)| Time     |
80-----------------------------------------------------------------------------------------
81|   0 | SELECT STATEMENT   |                    |     1 |     5 |   351   (2)| 00:00:05 |
82|   1 |  SORT AGGREGATE    |                    |     1 |     5 |            |          |
83|*  2 |   TABLE ACCESS FULL| TB_LHR_20160525_01 |     1 |     5 |   351   (2)| 00:00:05 |
84-----------------------------------------------------------------------------------------
85
86Predicate Information (identified by operation id):
87---------------------------------------------------
88
89   2 - filter("OBJECT_ID"=100)
90
912- Using SQL Profile
92--------------------
93Plan hash value: 661515879
94
95--------------------------------------------------------------------------------------------
96| Id  | Operation         | Name                   | Rows  | Bytes | Cost (%CPU)| Time     |
97--------------------------------------------------------------------------------------------
98|   0 | SELECT STATEMENT  |                        |     1 |     5 |     1   (0)| 00:00:01 |
99|   1 |  SORT AGGREGATE   |                        |     1 |     5 |            |          |
100|*  2 |   INDEX RANGE SCAN| TB_LHR_20160525_01_IDX |     1 |     5 |     1   (0)| 00:00:01 |
101--------------------------------------------------------------------------------------------
102
103Predicate Information (identified by operation id):
104---------------------------------------------------
105
106
107DBMS_SQLTUNE.REPORT_TUNING_TASK('SQL_PROFILE_TEST')
108----------------------------------------------------------------------------------------------------
109   2 - access("OBJECT_ID"=100)
110
111-------------------------------------------------------------------------------


这里可以看到,在优化建议中给出了新的查询计划。现在,我们决定接受这个建议,并且不重写语句。

第四步:接受profile


1LHR@dlhr> set autot on 2LHR@dlhr> select /*+no_index(TB_LHR_20160525_01 TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_LHR_20160525_01 where object_id = 100 ; 3 4  COUNT(*) 5---------- 6         1 7 8 9Execution Plan10----------------------------------------------------------1112Plan hash value: 36129893991314-----------------------------------------------------------------------------------------15| Id  | Operation          | Name               | Rows  | Bytes | Cost (%CPU)| Time     |16-----------------------------------------------------------------------------------------17|   0 | SELECT STATEMENT   |                    |     1 |     5 |   351   (2)| 00:00:05 |18|   1 |  SORT AGGREGATE    |                    |     1 |     5 |            |          |19|*  2 |   TABLE ACCESS FULL| TB_LHR_20160525_01 |     1 |     5 |   351   (2)| 00:00:05 |20-----------------------------------------------------------------------------------------2122Predicate Information (identified by operation id):23---------------------------------------------------2425   2 - filter("OBJECT_ID"=100)262728Statistics29----------------------------------------------------------30          0  recursive calls31          0  db block gets32       1249  consistent gets33          0  physical reads34          0  redo size35        526  bytes sent via SQL*Net to client36        520  bytes received via SQL*Net from client37          2  SQL*Net roundtrips to/from client38          0  sorts (memory)39          0  sorts (disk)40          1  rows processed41LHR@dlhr> execute dbms_sqltune.accept_sql_profile(task_name =>'sql_profile_test_SQLID', task_owner => 'LHR', replace => TRUE);4243PL/SQL procedure successfully completed.4445LHR@dlhr> set autot off46LHR@dlhr>  SELECT e.task_name, b.name, d.sql_text, extractvalue(value(h), '.') as hints47  2     FROM dba_sql_profiles d,48  3           dba_advisor_tasks e,49  4          SYS.SQLOBJ$DATA A,50  5          SYS.SQLOBJ$ B,51  6          TABLE(XMLSEQUENCE(EXTRACT(XMLTYPE(A.COMP_DATA),52  7                                    '/outline_data/hint'))) h53  8    where a.signature = b.signature54  9      and a.category = b.category55 10      and a.obj_type = b.obj_type56 11      and a.plan_id = b.plan_id57 12      and a.signature = d.signature 58 13      and d.task_id=e.task_id59 14      and d.name = 'SYS_SQLPROF_0154e728ad3f0000'60 15     ;6162TASK_NAME                      NAME63------------------------------ ------------------------------64SQL_TEXT65----------------------------------------------------------------------------------------------------66HINTS67----------------------------------------------------------------------------------------------------68sql_profile_test               SYS_SQLPROF_0154e728ad3f000069select /*+no_index(TB_LHR_20160525_01 TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_LHR_20160525_0170where object_id = 10071OPTIMIZER_FEATURES_ENABLE(default)7273sql_profile_test               SYS_SQLPROF_0154e728ad3f000074select /*+no_index(TB_LHR_20160525_01 TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_LHR_20160525_0175where object_id = 10076IGNORE_OPTIM_EMBEDDED_HINTSset autot on
2LHR@dlhr> select /*+no_index(TB_LHR_20160525_01 TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_LHR_20160525_01 where object_id = 100 ;
3
4  COUNT(*)
5----------
6         1
7
8
9Execution Plan
10----------------------------------------------------------
11
12Plan hash value: 3612989399
13
14-----------------------------------------------------------------------------------------
15| Id  | Operation          | Name               | Rows  | Bytes | Cost (%CPU)| Time     |
16-----------------------------------------------------------------------------------------
17|   0 | SELECT STATEMENT   |                    |     1 |     5 |   351   (2)| 00:00:05 |
18|   1 |  SORT AGGREGATE    |                    |     1 |     5 |            |          |
19|*  2 |   TABLE ACCESS FULL| TB_LHR_20160525_01 |     1 |     5 |   351   (2)| 00:00:05 |
20-----------------------------------------------------------------------------------------
21
22Predicate Information (identified by operation id):
23---------------------------------------------------
24
25   2 - filter("OBJECT_ID"=100)
26
27
28Statistics
29----------------------------------------------------------
30          0  recursive calls
31          0  db block gets
32       1249  consistent gets
33          0  physical reads
34          0  redo size
35        526  bytes sent via SQL*Net to client
36        520  bytes received via SQL*Net from client
37          2  SQL*Net roundtrips to/from client
38          0  sorts (memory)
39          0  sorts (disk)
40          1  rows processed
41LHR@dlhr> execute dbms_sqltune.accept_sql_profile(task_name =>'sql_profile_test_SQLID', task_owner => 'LHR', replace => TRUE);
42
43PL/SQL procedure successfully completed.
44
45LHR@dlhr> set autot off
46LHR@dlhr>  SELECT e.task_name, b.name, d.sql_text, extractvalue(value(h), '.') as hints
47  2     FROM dba_sql_profiles d,
48  3           dba_advisor_tasks e,
49  4          SYS.SQLOBJ$DATA A,
50  5          SYS.SQLOBJ$ B,
51  6          TABLE(XMLSEQUENCE(EXTRACT(XMLTYPE(A.COMP_DATA),
52  7                                    '/outline_data/hint'))) h
53  8    where a.signature = b.signature
54  9      and a.category = b.category
55 10      and a.obj_type = b.obj_type
56 11      and a.plan_id = b.plan_id
57 12      and a.signature = d.signature 
58 13      and d.task_id=e.task_id
59 14      and d.name = 'SYS_SQLPROF_0154e728ad3f0000'
60 15     ;
61
62TASK_NAME                      NAME
63------------------------------ ------------------------------
64SQL_TEXT
65----------------------------------------------------------------------------------------------------
66HINTS
67----------------------------------------------------------------------------------------------------
68sql_profile_test               SYS_SQLPROF_0154e728ad3f0000
69select /*+no_index(TB_LHR_20160525_01 TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_LHR_20160525_01
70where object_id = 100
71OPTIMIZER_FEATURES_ENABLE(default)
72
73sql_profile_test               SYS_SQLPROF_0154e728ad3f0000
74select /*+no_index(TB_LHR_20160525_01 TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_LHR_20160525_01
75where object_id = 100
76IGNORE_OPTIM_EMBEDDED_HINTS

在这里用了包DBMS_SQLTUNE的另一个函数:ACCEPT_SQL_PROFILE。其中,参数task_name即我们创建的优化建议任务的名称,name是profile的名字,可以是任意合法名称。此外这个函数还有其他一些函数,下面是这个函数的原型:


1DBMS_SQLTUNE.ACCEPT_SQL_PROFILE ( 2   task_name    IN  VARCHAR2, 3   object_id    IN  NUMBER   := NULL, 4   name         IN  VARCHAR2 := NULL, 5   description  IN  VARCHAR2 := NULL, 6   category     IN  VARCHAR2 := NULL; 7   task_owner   IN VARCHAR2  := NULL, 8   replace      IN BOOLEAN   := FALSE, 9   force_match  IN BOOLEAN   := FALSE)10 RETURN VARCHAR2;
2   task_name    IN  VARCHAR2,
3   object_id    IN  NUMBER   := NULL,
4   name         IN  VARCHAR2 := NULL,
5   description  IN  VARCHAR2 := NULL,
6   category     IN  VARCHAR2 := NULL;
7   task_owner   IN VARCHAR2  := NULL,
8   replace      IN BOOLEAN   := FALSE,
9   force_match  IN BOOLEAN   := FALSE)
10 RETURN VARCHAR2;

Description是profile的描述信息;task_owner是优化建议任务的所有者;replace为TRUE时,如果这个profile已经存在,就代替它;force_match为TURE时,表示与语句强制匹配,即强制使用绑定变量,和系统参数cursor_sharing设置为FORCE时类似,为FALSE时,与cursor_sharing设置为EXACT时类似,即完全匹配。

这里要特别提到的是category这个参数,你可以通过设置这个参数,制定特定会话使用这个profile。在10g中,每个会话都有一个新参数SQLTUNE_CATEGORY,他的默认值是DEFAULT。而我们在调用这个函数时,如果没有指定这个参数,那它的值也是DEFAULT,而如果我们给这个profile指定了一个其它的CATEGORY值,如FOR_TUNING,那么只有会话参SQLTUNE_CATEGORY也为FOR_TUNING时,才会使用这个porfile。为什么说这个参数很有用呢?试想一个这样的环境:你在一个生产系统上利用STA调优一条语句,STA已经给出了优化建议,但是你又不敢贸然实施它给出的建议(毕竟它只是机器嘛,不能完全信任),你就可以创建一个有特殊CATEGORY的profile,然后在你自己的会话中制定SQLTUNE_CATEGORY为这个特殊的CATEGORY,那就既可以看优化建议的实际效果又不影响生产环境。

此外可以通过视图DBA_SQL_PROFILES来查看已经创建的profile。

第五步:查看profile的效果


1LHR@dlhr> set autot on 2LHR@dlhr> select /*+no_index(TB_LHR_20160525_01 TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_LHR_20160525_01 where object_id = 100 ; 3 4  COUNT(*) 5---------- 6         1 7 8 9Execution Plan10----------------------------------------------------------11Plan hash value: 6615158791213--------------------------------------------------------------------------------------------14| Id  | Operation         | Name                   | Rows  | Bytes | Cost (%CPU)| Time     |15--------------------------------------------------------------------------------------------16|   0 | SELECT STATEMENT  |                        |     1 |     5 |     1   (0)| 00:00:01 |17|   1 |  SORT AGGREGATE   |                        |     1 |     5 |            |          |18|*  2 |   INDEX RANGE SCAN| TB_LHR_20160525_01_IDX |     1 |     5 |     1   (0)| 00:00:01 |19--------------------------------------------------------------------------------------------2021Predicate Information (identified by operation id):22---------------------------------------------------2324   2 - access("OBJECT_ID"=100)2526Note27-----28   - SQL profile "SYS_SQLPROF_0154e728ad3f0000" used for this statement293031Statistics32----------------------------------------------------------33          1  recursive calls34          0  db block gets35          2  consistent gets36          0  physical reads37          0  redo size38        526  bytes sent via SQL*Net to client39        520  bytes received via SQL*Net from client40          2  SQL*Net roundtrips to/from client41          0  sorts (memory)42          0  sorts (disk)43          1  rows processedset autot on
2LHR@dlhr> select /*+no_index(TB_LHR_20160525_01 TB_LHR_20160525_01_idx)*/count(*) from lhr.TB_LHR_20160525_01 where object_id = 100 ;
3
4  COUNT(*)
5----------
6         1
7
8
9Execution Plan
10----------------------------------------------------------
11Plan hash value: 661515879
12
13--------------------------------------------------------------------------------------------
14| Id  | Operation         | Name                   | Rows  | Bytes | Cost (%CPU)| Time     |
15--------------------------------------------------------------------------------------------
16|   0 | SELECT STATEMENT  |                        |     1 |     5 |     1   (0)| 00:00:01 |
17|   1 |  SORT AGGREGATE   |                        |     1 |     5 |            |          |
18|*  2 |   INDEX RANGE SCAN| TB_LHR_20160525_01_IDX |     1 |     5 |     1   (0)| 00:00:01 |
19--------------------------------------------------------------------------------------------
20
21Predicate Information (identified by operation id):
22---------------------------------------------------
23
24   2 - access("OBJECT_ID"=100)
25
26Note
27-----
28   - SQL profile "SYS_SQLPROF_0154e728ad3f0000" used for this statement
29
30
31Statistics
32----------------------------------------------------------
33          1  recursive calls
34          0  db block gets
35          2  consistent gets
36          0  physical reads
37          0  redo size
38        526  bytes sent via SQL*Net to client
39        520  bytes received via SQL*Net from client
40          2  SQL*Net roundtrips to/from client
41          0  sorts (memory)
42          0  sorts (disk)
43          1  rows processed

从NOTE部分可以看到,语句采用了profile中的数据,创建了新的查询计划。并且在查询计划中还有一些附加信息,表明这个语句是采用了“SYS_SQLPROF_0154e728ad3f0000”这个Profile,而不是根据对象上面的统计数据来生成的查询计划。

但上述方法主要是依赖sql tuning advisor,如果它无法生成你想要的执行计划.你还可以通过手动的方式,通过sql profile把hint加进去.复杂的SQL的hint可以采用脚本coe_xfr_sql_profile.sql来产生原语句的outline data和加hint语句的outline data,然后替换对应的SYS.SQLPROF_ATTR,最后执行生成的sql就可以了。

使用PLSQL DEVELOPER 11查看执行计划,如下图,新版本的好处:

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本文选自《Oracle程序员面试笔试宝典》,作者:李华荣。



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