1. 引子
Oracle系統為了合理分配和使用系統的資源提出了概要檔案的概念。所謂概要檔案，就是一份描述如何使用系統的資源(主要是CPU資源)的配置檔案。將概要檔案賦予某個資料庫使用者，在使用者連線並訪問資料庫伺服器時，系統就按照概要檔案給他分配資源。
包括:
1、管理資料庫系統資源。
利用Profile來分配資源限額，必須把初始化引數resource_limit設定為true預設是TRUE的。
2、管理資料庫口令及驗證方式。
預設給使用者分配的是DEFAULT概要檔案，將該檔案賦予了每個建立的使用者。但該檔案對資源沒有任何限制，因此管理員常常需要根據自己資料庫系統的環境自行建立概要檔案。
2. 概要檔案限制
概要檔案主要可以對資料庫系統如下指標進行限制。
1）使用者的最大併發會話數（SESSION_PER_USER)
2）每個會話的CPU時鐘限制（CPU_PER_SESSION）
3）每次呼叫的CPU時鐘限制，呼叫包含解析、執行命令和獲取資料等等。（CPU_PER_CALL）
4）最長連線時間。一個會話的連線時間超過指定時間之後，Oracle會自動的斷開連線（CONNECT_TIME）
5）最長空閒時間。如果一個會話處於空閒狀態超過指定時間，Oracle會自動斷開連線（IDLE_TIME）
6）每個會話可以讀取的最大資料塊數量（LOGICAL_READS_PER_SESSION）
7）每次呼叫可以讀取的最大資料塊數量（LOGICAL_READS_PER_CALL）
8）SGA私有區域的最大容量（PRIVATE_SGA）
概要檔案對口令的定義和限制如下：
1）登入失敗的最大嘗試次數（FAILED_LOGIN_ATTEMPTS）
2）口令的最長有效期(PASSWORD_LIFE_TIME)
3）口令在可以重用之前必須修改的次數(PASSWORD_REUSE_MAX)
4）口令在可以重用之前必須經過的天數(PASSWORD_REUSE_TIME)
5）超過登入失敗的最大允許嘗試次數後，賬戶被鎖定的天數
6）指定用於判斷口令複雜度的函式名
在指定概要檔案之後，DBA可以手工的將概要檔案賦予每個使用者。但是概要檔案不是立即生效，而是要將初始化引數檔案中的引數RESOURCE_LIMIT設定為TRUE之後，概要檔案才會生效。
3. SQL PROFILE
SQL PROFILE在ORACLE10g中引入，主要目的側重於SQL優化，彌補了儲存概要的缺點.
DBA可以使用SQL調整顧問(STA)或SQL訪問顧問(SAA)來識別可以得到更好效能的SQL語句，
這些語句可以儲存在SQL調整集、一個AWR快照或儲存在當前的庫快取中，一旦識別出調整候選者， 這些顧問程式就開始分析捕獲到的語句以期獲得更好的效能，然後生成專用的語句擴充套件(就叫做SQL配置檔案)並重寫SQL語句以在執行期間獲取更佳的效能。
與儲存概要類似，一個SQL配置檔案提供了使用更好的執行計劃的能力(如果這個執行計
劃是可用的)，SQL配置檔案也可以象儲存概要一樣分階段執行，或限制到對特定會話才能執行該SQL配置檔案，但是大多數重要的改進超過了儲存概要.
SQLProfile對於一下型別語句有效：
SELECT語句；
UPDATE語句；
INSERT語句（僅當使用SELECT子句時有效）；
DELETE語句；
CREATE語句（僅當使用SELECT子句時有效）；
MERGE語句（僅當作UPDATE和INSERT操作時有效）。
另外，使用SQL Profile還必須有CREATE ANY SQL PROFILE、DROP ANY SQL PROFILE和ALTER ANY SQL PROFILE等系統許可權。
4. 測試一
建立表
tpcc@TOADDB> create table t1 as selectobject_id,object_name from dba_objects where rownum<=50000;
Table created.
tpcc@TOADDB> create table t2 as select * fromdba_objects;
Table created.
建立索引：
tpcc@TOADDB> create index t2_idx on t2(object_id);
Index created.
收集統計資訊：
tpcc@TOADDB> execdbms_stats.gather_table_stats(user,`t1`,cascade=>true,method_opt=>`forall columns size 1`);
PL/SQL procedure successfully completed.
tpcc@TOADDB> execdbms_stats.gather_table_stats(user,`t1`,cascade=>true,method_opt=>`forall columns size 1`);
PL/SQL procedure successfully completed.
執行無HINT的SQL
tpcc@TOADDB> set autotrace on
tpcc@TOADDB> select t1.*,t2.owner from t1,t2 wheret1.object_name like `%T1%` and t1.object_id=t2.object_id;
42 rows selected.
Execution Plan
———————————————————-
Plan hash value: 1838229974
—————————————————————————
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
—————————————————————————
| 0| SELECT STATEMENT | | 2500 | 97K| 498 (1)| 00:00:01 |
|* 1| HASH JOIN | | 2500 | 97K| 498 (1)| 00:00:01 |
|* 2| TABLE ACCESS FULL| T1 | 2500 | 72500 | 68 (0)| 00:00:01 |
| 3| TABLE ACCESS FULL| T2 | 92021 | 988K| 430 (1)| 00:00:01 |
—————————————————————————
Predicate Information (identified byoperation id):
—————————————————
1-access(“T1″.”OBJECT_ID”=”T2″.”OBJECT_ID”)
2- filter(“T1″.”OBJECT_NAME” LIKE `%T1%` AND”T1″.”OBJECT_NAME” IS
NOT NULL)
Statistics
———————————————————-
1 recursive calls
0 dbblock gets
1789 consistent gets
0 physical reads
0 redosize
2350 bytes sent via SQL*Net toclient
573 bytes received via SQL*Net from client
4 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
42 rowsprocessed
執行帶Hint的SQL
SQL>select /*+ use_nl(t1 t2) index(t2)*/ t1.*,t2.owner from t1,t2 where t1.object_name like `%T1%` and t1.object_id=t2.object_id;
42 rows selected.
Execution Plan
———————————————————-
Plan hash value: 1022743391
—————————————————————————————
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|Time |
—————————————————————————————
| 0| SELECT STATEMENT | | 2500 | 97K| 5069 (1)|00:00:01 |
| 1| NESTED LOOPS | | 2500| 97K| 5069 (1)| 00:00:01 |
| 2| NESTED LOOPS | | 2500 | 97K| 5069 (1)| 00:00:01 |
|* 3| TABLE ACCESS FULL | T1 | 2500 | 72500 | 68 (0)|00:00:01 |
|* 4| INDEX RANGE SCAN |T2_IDX | 1 | | 1 (0)| 00:00:01 |
| 5| TABLE ACCESS BY INDEX ROWID| T2 | 1 | 11 | 2 (0)|00:00:01 |
—————————————————————————————
Predicate Information (identified byoperation id):
—————————————————
3- filter(“T1″.”OBJECT_NAME” LIKE `%T1%` AND”T1″.”OBJECT_NAME” IS NOT
NULL)
4-access(“T1″.”OBJECT_ID”=”T2″.”OBJECT_ID”)
Statistics
———————————————————-
1 recursive calls
0 dbblock gets
304 consistent gets
24 physical reads
0 redosize
2350 bytes sent via SQL*Net toclient
573 bytes received via SQL*Net from client
4 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
42 rowsprocessed
使用SQL PROFILE
查詢執行SQL的SQL_ID
tpcc@TOADDB> select sql_id,sql_text from v$sqlwhere sql_text like `%t1.object_name%`;
SQL_ID
————-
SQL_TEXT
—————————————————————————————————-
4zbqykx89yc8v
select t1.*,t2.owner from t1,t2 wheret1.object_name like `%T1%` and t1.object_id=t2.object_id
18bphz37dajq9
select /*+ use_nl(t1 t2) index(t2) */t1.*,t2.owner from t1,t2 where t1.object_name like `%T1%` and
t1.object_id=t2.object_id
執行儲存過程如下：
var tuning_task varchar2(100);
DECLARE
l_sql_id v$session.prev_sql_id%TYPE;
l_tuning_task VARCHAR2(30);
BEGIN
l_sql_id:=`4zbqykx89yc8v`;
l_tuning_task := dbms_sqltune.create_tuning_task(sql_id =>l_sql_id);
:tuning_task:=l_tuning_task;
dbms_sqltune.execute_tuning_task(l_tuning_task);
dbms_output.put_line(l_tuning_task);
END;
/
TASK_114
PL/SQL procedure successfully completed.
檢視task的名字
tpcc@TOADDB> print tuning_task;
TUNING_TASK
—————————————————————————————————-
TASK_114
檢視執行報告
set long 99999
col comments format a200
SELECT dbms_sqltune.report_tuning_task(:tuning_task)COMMENTS FROM dual;
COMMENTS
—————————————————————————————————-
GENERAL INFORMATION SECTION
——————————————————————————-
Tuning Task Name : TASK_114
Tuning Task Owner : TPCC
Workload Type : Single SQL Statement
Scope : COMPREHENSIVE
Time Limit(seconds): 1800
Completion Status : COMPLETED
Started at : 03/06/2016 05:27:21
Completed at : 03/06/2016 05:27:24
——————————————————————————-
Schema Name: TPCC
SQL ID : 4zbqykx89yc8v
SQL Text : select t1.*,t2.owner from t1,t2 where t1.object_name like `%T1%`
and t1.object_id=t2.object_id
——————————————————————————-
FINDINGS SECTION (1 finding)
——————————————————————————-
1- SQL Profile Finding (see explain planssection below)
——————————————————–
Apotentially better execution plan was found for this statement.
Recommendation (estimated benefit: 83.08%)
——————————————
-Consider accepting the recommended SQL profile.
executedbms_sqltune.accept_sql_profile(task_name => `TASK_114`,
task_owner =>`TPCC`, replace => TRUE);
Validation results
——————
TheSQL profile was tested by executing both its plan and the original plan
andmeasuring their respective execution statistics. A plan may have been
only partially executed if the other could be run to completion in lesstime.
Original Plan With SQL Profile % Improved
————- —————- ———-
Completion Status: COMPLETE COMPLETE
Elapsed Time (s): .012865 .004556 64.58 %
CPUTime (s): .0124 .0045 63.7%
User I/O Time (s): 0 0
Buffer Gets: 1787 302 83.1%
Physical Read Requests: 0 0
Physical Write Requests: 0 0
Physical Read Bytes: 0 0
Physical Write Bytes: 0 0
Rows Processed: 42 42
Fetches: 42 42
Executions: 1 1
Notes
—–
1.Statistics for the original plan were averaged over 10 executions.
2.Statistics for the SQL profile plan were averaged over 10 executions.
——————————————————————————-
EXPLAIN PLANS SECTION
——————————————————————————-
1- Original With Adjusted Cost
——————————
Plan hash value: 1838229974
—————————————————————————
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
—————————————————————————
| 0| SELECT STATEMENT | | 42 | 1680 | 498 (1)| 00:00:01 |
|* 1| HASH JOIN | | 42 | 1680 | 498 (1)| 00:00:01 |
|* 2| TABLE ACCESS FULL| T1 | 42 | 1218 | 68 (0)| 00:00:01 |
| 3| TABLE ACCESS FULL| T2 | 92021 | 988K| 430 (1)| 00:00:01 |
—————————————————————————
Predicate Information (identified byoperation id):
—————————————————
1-access(“T1″.”OBJECT_ID”=”T2″.”OBJECT_ID”)
2- filter(“T1″.”OBJECT_NAME” LIKE `%T1%` AND”T1″.”OBJECT_NAME” IS
NOT NULL)
2- Using SQL Profile
——————–
Plan hash value: 1022743391
—————————————————————————————
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|Time |
—————————————————————————————
| 0| SELECT STATEMENT | | 42 | 1680 | 152 (0)|00:00:01 |
| 1| NESTED LOOPS | | 42 | 1680 | 152 (0)| 00:00:01 |
| 2| NESTED LOOPS | | 42 | 1680 | 152 (0)| 00:00:01 |
|* 3| TABLE ACCESS FULL | T1 | 42 | 1218 | 68 (0)| 00:00:01 |
|* 4| INDEX RANGE SCAN |T2_IDX | 1 | | 1 (0)| 00:00:01 |
| 5| TABLE ACCESS BY INDEX ROWID| T2 | 1 | 11 | 2 (0)|00:00:01 |
—————————————————————————————
Predicate Information (identified byoperation id):
—————————————————
3- filter(“T1″.”OBJECT_NAME” LIKE `%T1%` AND”T1″.”OBJECT_NAME” IS NOT
NULL)
4-access(“T1″.”OBJECT_ID”=”T2″.”OBJECT_ID”)
——————————————————————————-
接受分析建議
報告中給出了執行方法，如上紅色部分
接受報告的建議，驗證一下如下：
tpcc@TOADDB> execute dbms_sqltune.accept_sql_profile(task_name=> `TASK_114`,task_owner => `TPCC`, replace => TRUE);
PL/SQL procedure successfully completed.
執行測試
再執行原先命令如下：
tpcc@TOADDB> select t1.*,t2.owner from t1,t2 wheret1.object_name like `%T1%` and t1.object_id=t2.object_id;
42 rows selected.
Execution Plan
———————————————————-
Plan hash value: 1022743391
—————————————————————————————
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|Time |
—————————————————————————————
| 0| SELECT STATEMENT | | 42 | 1680 | 152 (0)|00:00:01 |
| 1| NESTED LOOPS | | 42| 1680 | 152 (0)|00:00:01 |
| 2| NESTED LOOPS | | 42 | 1680 | 152 (0)| 00:00:01 |
|* 3| TABLE ACCESS FULL | T1 | 42 | 1218 | 68 (0)| 00:00:01 |
|* 4| INDEX RANGE SCAN |T2_IDX | 1 | | 1 (0)| 00:00:01 |
| 5| TABLE ACCESS BY INDEX ROWID| T2 | 1 | 11 | 2 (0)|00:00:01 |
—————————————————————————————
Predicate Information (identified byoperation id):
—————————————————
3- filter(“T1″.”OBJECT_NAME” LIKE `%T1%` AND”T1″.”OBJECT_NAME” IS NOT
NULL)
4-access(“T1″.”OBJECT_ID”=”T2″.”OBJECT_ID”)
Note
—–
– SQL profile”SYS_SQLPROF_01534b8309b90000″ used for this statement
– this is an adaptive plan
Statistics
———————————————————-
35 recursive calls
0 dbblock gets
317 consistent gets
1 physical reads
0 redosize
2350 bytes sent via SQL*Net toclient
573 bytes received via SQL*Net from client
4 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
42 rowsprocessed
啟用了PROFILE，PS：如果執行中多加幾個空格，並不會影響PROFILE的生效的。
5. 維護操作
禁用命令
如下：
begin
dbms_sqltune.alter_sql_profile(
name => `SYS_SQLPROF_01534b8309b90000`,
attribute_name => `status`,
value => `disabled`);
end;
/
啟用命令
如下：
begin
dbms_sqltune.alter_sql_profile(
name => `SYS_SQLPROF_01534b8309b90000`,
attribute_name => `status`,
value => `enabled`);
end;
/
檢視使用的PROFILE
如下：
SQL>SELECT task_name,status FROMUSER_ADVISOR_TASKS ;
刪除PROFILE
BEGIN
DBMS_SQLTUNE.DROP_SQL_PROFILE(name => `SYS_SQLPROF_01534b8309b90000`);
END;
/
———————
作者：badman250
來源：CSDN
原文：https://blog.csdn.net/notbaron/article/details/50830910
版權宣告：本文為博主原創文章，轉載請附上博文連結！