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    Oracle固定执行计划之SQL PROFILE概要文件详解

    1.  引子

    Oracle系统为了合理分配和使用系统的资源提出了概要文件的概念。所谓概要文件,就是一份描述如何使用系统的资源(主要是CPU资源)的配置文件。将概要文件赋予某个数据库用户,在用户连接并访问数据库服务器时,系统就按照概要文件给他分配资源。

    包括:

    1、管理数据库系统资源。

    利用Profile来分配资源限额,必须把初始化参数resource_limit设置为true默认是TRUE的。

    2、管理数据库口令及验证方式。

    默认给用户分配的是DEFAULT概要文件,将该文件赋予了每个创建的用户。但该文件对资源没有任何限制,因此管理员常常需要根据自己数据库系统的环境自行建立概要文件。

    2.  概要文件限制

    概要文件主要可以对数据库系统如下指标进行限制。

    1)用户的最大并发会话数(SESSION_PER_USER)

    2)每个会话的CPU时钟限制(CPU_PER_SESSION)

    3)每次调用的CPU时钟限制,调用包含解析、执行命令和获取数据等等。(CPU_PER_CALL)

    4)最长连接时间。一个会话的连接时间超过指定时间之后,Oracle会自动的断开连接(CONNECT_TIME)

    5)最长空闲时间。如果一个会话处于空闲状态超过指定时间,Oracle会自动断开连接(IDLE_TIME)

    6)每个会话可以读取的最大数据块数量(LOGICAL_READS_PER_SESSION)

    7)每次调用可以读取的最大数据块数量(LOGICAL_READS_PER_CALL)

    8)SGA私有区域的最大容量(PRIVATE_SGA)

    概要文件对口令的定义和限制如下:

    1)登录失败的最大尝试次数(FAILED_LOGIN_ATTEMPTS)

    2)口令的最长有效期(PASSWORD_LIFE_TIME)

    3)口令在可以重用之前必须修改的次数(PASSWORD_REUSE_MAX)

    4)口令在可以重用之前必须经过的天数(PASSWORD_REUSE_TIME)

    5)超过登录失败的最大允许尝试次数后,账户被锁定的天数

    6)指定用于判断口令复杂度的函数名

    在指定概要文件之后,DBA可以手工的将概要文件赋予每个用户。但是概要文件不是立即生效,而是要将初始化参数文件中的参数RESOURCE_LIMIT设置为TRUE之后,概要文件才会生效。

    3.  SQL PROFILE

    SQL PROFILE在ORACLE10g中引入,主要目的侧重于SQL优化,弥补了存储概要的缺点.

    DBA可以使用SQL调整顾问(STA)或SQL访问顾问(SAA)来识别可以得到更好性能的SQL语句, 

    这些语句可以保存在SQL调整集、一个AWR快照或保存在当前的库缓存中,一旦识别出调整候选者, 这些顾问程序就开始分析捕获到的语句以期获得更好的性能,然后生成专用的语句扩展(就叫做SQL配置文件)并重写SQL语句以在执行期间获取更佳的性能。

      与存储概要类似,一个SQL配置文件提供了使用更好的执行计划的能力(如果这个执行计

    划是可用的),SQL配置文件也可以象存储概要一样分阶段执行,或限制到对特定会话才能执行该SQL配置文件,但是大多数重要的改进超过了存储概要.

     SQLProfile对于一下类型语句有效:

        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。

    4.  测试一

    创建表

    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.

    创建索引:

    tpcc@TOADDB> create index t2_idx on t2(object_id);
    Index created.

    收集统计信息:

    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.

    执行无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

    执行带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

    查找执行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

    运行存储过程如下:

    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.

    查看task的名字

    tpcc@TOADDB> print tuning_task;
    TUNING_TASK
    ----------------------------------------------------------------------------------------------------
    TASK_114

    查看执行报告

    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")
    -------------------------------------------------------------------------------

    接受分析建议

    报告中给出了执行方法,如上红色部分

    接受报告的建议,验证一下如下:

    tpcc@TOADDB> execute dbms_sqltune.accept_sql_profile(task_name=> 'TASK_114',task_owner => 'TPCC', replace => TRUE);
    PL/SQL procedure successfully completed.

    执行测试

    再执行原先命令如下:

    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

    启用了PROFILE,PS:如果执行中多加几个空格,并不会影响PROFILE的生效的。

    5.  维护操作

    禁用命令
    如下:

    begin 
    dbms_sqltune.alter_sql_profile( 
    name   => 'SYS_SQLPROF_01534b8309b90000', 
    attribute_name => 'status', 
    value   => 'disabled'); 
    end; 
    /

    启用命令
    如下:

    begin 
    dbms_sqltune.alter_sql_profile( 
    name   => 'SYS_SQLPROF_01534b8309b90000', 
    attribute_name => 'status', 
    value   => 'enabled'); 
    end; 
    /

    查看使用的PROFILE

    如下:

    SQL>SELECT task_name,status FROMUSER_ADVISOR_TASKS ;

    删除PROFILE

    BEGIN 
     DBMS_SQLTUNE.DROP_SQL_PROFILE(name => 'SYS_SQLPROF_01534b8309b90000'); 
    END; 

    总结

    以上所述是小编给大家介绍的Oracle固定执行计划之SQL PROFILE概要文件 ,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对脚本之家网站的支持!

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    Oracle固定执行计划之SQL PROFILE概要文件详解 Oracle,固定,执行,计划,之,