PLSQL_性能优化系列18_Oracle Explain Plan解析计划通过Baseline绑定

2015-05-28 Created By BaoXinjian

一、摘要

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1. 应用场景

当运行很久的Job突然出现性能问题时，并排除数据量突然变大，可能原因有执行的脚本的某些对应的SQL的解析计划变更

2. 解决步骤

Step1. 通过对应的User或者其他信息查找Session ID

Step2. 通过Session_ID查看该SQL_ID历史的解析计划变换 

Step3. 如果最近发生解析计划变更，并导致效率变慢，通过SPM绑定之前的解析计划 

Step4. 确定解析计划是否绑定 

Step5. 如果脚本还在运行，让客户停掉脚本，并重新运行，以测试绑定的新的解析计划是否满足期望 

Step6. 如果绑定的解析计划并不能解决性能问题，验证后将其删除

 

二、步骤

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Step1. 通过对应的User或者其他信息查找Session ID

select sql_id, username, osuser, machine, program from v$session where username = 'gavin'

Step2. 查看该SQL_ID历史的解析计划变换

select distinct a.instance_number, trunc(b.begin_interval_time, 'mi'), sql_id, plan_hash_value from dba_hist_sqlstat a, dba_hist_snapshot b where a.snap_id = b.snap_id and sql_id = '089dbukv1aanh'

 order by 2, 1

Step3. 如果最近发生解析计划变更，并导致效率变慢，通过SPM绑定之前的解析计划 (脚本coe_xfr_sql_baseline.sql)

SQL>@D:\Gavin\coe_xfr_sql_baseline.sql Parameter 1: SQL_ID (required) Enter value for 1: 089dbukv1aanh SNAP_DATE SQL_ID PLAN_HASH_VALUE --------------- ------------- --------------------

2015/05/20      089dbukv1aanh           1388734953

2015/05/21      089dbukv1aanh           1388734953

2015/05/22      089dbukv1aanh           1388734953

2015/05/23      089dbukv1aanh           1388734953

2015/05/24      089dbukv1aanh           1388734953

2015/05/25      089dbukv1aanh           1388734953

2015/05/26      089dbukv1aanh           1388734953

2015/05/27      089dbukv1aanh           1388734953

2015/05/28      089dbukv1aanh           1388734953 Parameter 2: PLAN_HASH_VALUE (required) Enter value for 2: 1388734953



Values passed to coe_xfr_sql_baseline: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SQL_ID: "089dbukv1aanh" PLAN_HASH_VALUE: "1388734953" SQL>SET ECHO OFF; SQL tuning set SS_089dbukv1aanh_1388734953 created. SQLSET_NAME SQLSET_OWNER SQL_ID PLAN_HASH_VALUE ------------------------------ ------------------------------ ------------------------------ -------

SS_089dbukv1aanh_1388734953    GAVIN                          089dbukv1aanh                            1388734953 Plans Loaded: 1 sys_sql_handle: "SYS_SQL_70445f05461a3cd3" sys_plan_name: "SQL_PLAN_70j2z0p31ng6m125daea2" 1 plan(s) modified description: "SQL_ID: 089DBUKV1AANH PLAN HASH VALUE: 1388734953 CREATED BY COE_XF SQL tuning set SS_089dbukv1aanh_1388734953 dropped. SQL>REM SQL>REM SQL Plan Baseline SQL>REM ~~~~~~~~~~~~~~~~~ SQL>REM SQL>SELECT signature, sql_handle, plan_name, enabled, accepted, fixed--, reproduced (avail on 11.2.0

  2    FROM dba_sql_plan_baselines WHERE plan_name = :plan_name; SIGNATURE SQL_HANDLE PLAN_NAME ENA ACC FIX -------------------- ------------------------------ ------------------------------ --- --- ---

 8089695306919853267 SYS_SQL_70445f05461a3cd3 SQL_PLAN_70j2z0p31ng6m125daea2 YES YES YES SQL> SQL>col description for a100 SQL>SELECT description 2    FROM dba_sql_plan_baselines WHERE plan_name = :plan_name; DESCRIPTION ----------------------------------------------------------------------------------------------------

SQL_ID: 089DBUKV1AANH PLAN HASH VALUE: 1388734953 CREATED BY COE_XFR_SQL_BASELINE.SQL SQL>SET ECHO OFF; coe_xfr_sql_baseline completed. 

Step4. 确定解析计划是否绑定

select sql_handle, plan_name, sql_text, creator, description, enabled, accepted, fixed from dba_sql_plan_baselines where description like '%089dbukv1aanh%'

Step5. 如果脚本还在运行，让客户停掉脚本，并重新运行，以测试绑定的新的解析计划是否满足期望

alter system disconnect session '102,102' immediate; 

Step6. 如果绑定的解析计划并不能解决性能问题，验证后将其删除

declare l_plan number; begin l_plan := dbms_spm.drop_sql_plan_baseline('SYS_SQL_70445f05461a3cd3', 'SQL_PLAN_70j2z0p31ng6m125daea2'); dbms_output.put_line('l_pan=' || l_plan); end;

 

三、代码

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Oracle Metalink下载代码 - ce_xfr_sql_baseline.sql

SPO coe_xfr_sql_baseline.log;

SET DEF ON TERM OFF ECHO ON FEED OFF VER OFF HEA ON LIN 2000 PAGES 100 LONG 8000000 LONGC 800000 TRIMS ON TI OFF TIMI OFF SERVEROUT ON SIZE 1000000 NUM 20 SQLP SQL>;

SET SERVEROUT ON SIZE UNL;

REM

REM Created according to coe_load_sql_baseline.sql and MOS note 789888.1 2013/06/10

REM

REM AUTHOR

REM   gavin.bao

REM

REM SCRIPT

REM   coe_xfr_sql_baseline.sql

REM

REM DESCRIPTION

REM   This script loads a plan from AWR into the SQL

REM   Plan Baseline of the specified SQL.

REM

REM PRE-REQUISITES

REM   1. Have in AWR the text for the specified SQL.

REM

REM PARAMETERS

REM   1. SQL_ID (required)

REM   2. PLAN_HASH_VALUE in AWR (required)

REM

REM EXECUTION

REM   1. Connect into SQL*Plus as user with access to data dictionary

REM      and privileges to create SQL Plan Baselines. Do not use SYS.

REM   2. Execute script coe_xfr_sql_baseline.sql passing first two

REM      parameters inline or until requested by script.

REM

REM EXAMPLE

REM   # sqlplus system

REM   SQL> START coe_xfr_sql_baseline.sql gnjy0mn4y9pbm b8f3mbkd8bkgh

REM   SQL> START coe_xfr_sql_baseline.sql;

REM

REM NOTES

REM   1. This script works on 11g or higher.

REM   2. For a similar script for 10g use coe_xfr_sql_profile.sql,

REM      which uses custom SQL Profiles instead of SQL Baselines.

REM   3. For possible errors see coe_xfr_sql_baseline.log

REM   4. Use a DBA user but not SYS. Do not connect as SYS as the staging

REM      table cannot be created in SYS schema and you will receive an error:

REM      ORA-19381: cannot create staging table in SYS schema

REM

SET TERM ON ECHO OFF;

PRO

PRO Parameter 1:

PRO SQL_ID (required)

PRO

DEF sql_id = '&1';

PRO

col SNAP_DATE for a15

select distinct to_char(trunc(b.BEGIN_INTERVAL_TIME),'yyyy/mm/dd') SNAP_DATE,SQL_ID,PLAN_HASH_VALUE

from dba_hist_sqlstat a,dba_hist_snapshot b

where SQL_ID=TRIM('&&sql_id.')

and a.snap_id=b.snap_id order by 1;

PRO

PRO Parameter 2:

PRO PLAN_HASH_VALUE (required)

PRO

DEF plan_hash_value = '&2';

PRO

PRO Values passed to coe_xfr_sql_baseline:

PRO ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

PRO SQL_ID: "&&sql_id."

PRO PLAN_HASH_VALUE: "&&plan_hash_value."

PRO

WHENEVER SQLERROR EXIT SQL.SQLCODE;

SET TERM OFF ECHO ON;



-- trim parameters

COL sql_id NEW_V sql_id FOR A30;

COL plan_hash_value NEW_V plan_hash_value FOR A30;

SELECT TRIM('&&sql_id.') sql_id, TRIM('&&plan_hash_value.') plan_hash_value FROM DUAL;



-- open log file

SPO coe_xfr_sql_baseline_&&sql_id..log;

GET coe_xfr_sql_baseline.log;

.



-- get user

COL connected_user NEW_V connected_user FOR A30;

SELECT USER connected_user FROM DUAL;



VAR sql_text CLOB;

VAR plan_name VARCHAR2(30);

VAR b_snap_id NUMBER;

VAR e_snap_id NUMBER;

VAR ss_name VARCHAR2(100);

EXEC :sql_text := NULL;

EXEC :plan_name := NULL;

EXEC :b_snap_id := NULL;

EXEC :e_snap_id := NULL;

EXEC :ss_name := 'SS_'||TRIM('&&sql_id.')||'_'||TRIM('&&plan_hash_value.');



-- get sql_text from awr

BEGIN

    SELECT REPLACE(sql_text, CHR(00), ' ')

      INTO :sql_text

      FROM dba_hist_sqltext

     WHERE sql_id = TRIM('&&sql_id.')

       AND sql_text IS NOT NULL

       AND ROWNUM = 1;

EXCEPTION

  WHEN OTHERS THEN

    DBMS_OUTPUT.PUT_LINE('getting sql_text from awr: '||SQLERRM);

    :sql_text := NULL;

END;

/



-- sql_text as found

SELECT :sql_text FROM DUAL;



-- check is sql_text for sql is available

SET TERM ON;

SET ECHO OFF;

BEGIN

  IF :sql_text IS NULL THEN

    RAISE_APPLICATION_ERROR(-20100, 'SQL_TEXT for SQL_ID &&sql_id. was not found in AWR (dba_hist_sqltext).');

  END IF;

END;

/





-- get snap id

DECLARE

  l_count NUMBER;

BEGIN

  SELECT min(SNAP_ID), max(SNAP_ID)

    INTO :b_snap_id, :e_snap_id

    FROM dba_hist_sqlstat

   WHERE sql_id = TRIM('&&sql_id.')

     AND plan_hash_value = TO_NUMBER(TRIM('&&plan_hash_value.'));



   IF (:b_snap_id is null or :e_snap_id is null) THEN

     RAISE_APPLICATION_ERROR(-20110, 'PHV &&plan_hash_value. for SQL_ID &&sql_id. was not be found in AWR (dba_hist_sqlstat).');

   END IF;

END;

/





DECLARE

  --ss_name VARCHAR2(100) default 'SS_'||TRIM('&&sql_id.')||'_'||TRIM('&&plan_hash_value.');

  baseline_ref_cursor DBMS_SQLTUNE.SQLSET_CURSOR;

BEGIN

  -- create sql_plan_baseline for sql using plan from AWR

  DBMS_SQLTUNE.CREATE_SQLSET(:ss_name);

  open baseline_ref_cursor for

  select VALUE(p) from

  table(DBMS_SQLTUNE.SELECT_WORKLOAD_REPOSITORY(:b_snap_id, :e_snap_id,

                                                'sql_id='||CHR(39)||TRIM('&&sql_id.')||CHR(39)||

                                                ' and plan_hash_value='||TRIM('&&plan_hash_value.'),

                                                NULL,NULL,NULL,NULL,NULL,NULL,'ALL')) p;

  DBMS_SQLTUNE.LOAD_SQLSET(:ss_name, baseline_ref_cursor);

  DBMS_OUTPUT.PUT_LINE('SQL tuning set '||:ss_name||' created.');

END;

/





-- display details of the SQL tuning set

col PLAN_HASH_VALUE clear

select SQLSET_NAME,SQLSET_OWNER,SQL_ID,PLAN_HASH_VALUE from dba_sqlset_statements where sqlset_name = :ss_name ;



-- load the plan from SQL tuning set into baseline

declare

  plans NUMBER;

  description VARCHAR2(500);

  sys_sql_handle VARCHAR2(30);

  sys_plan_name VARCHAR2(30);

begin

  plans := dbms_spm.load_plans_from_sqlset(sqlset_name => :ss_name,

                                              sqlset_owner => USER,

                                              fixed => 'YES',

                                              enabled => 'YES');

  commit;

  DBMS_OUTPUT.PUT_LINE('Plans Loaded: '||plans);



  -- find handle and plan_name for sql_plan_baseline just created

  SELECT sql_handle, plan_name

    INTO sys_sql_handle, sys_plan_name

    FROM dba_sql_plan_baselines

   WHERE creator = USER

     AND origin = 'MANUAL-LOAD'

     AND created = ( -- past 1 minute only

  SELECT MAX(created) max_created

    FROM dba_sql_plan_baselines

   WHERE creator = USER

     AND origin = 'MANUAL-LOAD'

     AND created > SYSDATE - (1/24/60));

  DBMS_OUTPUT.PUT_LINE('sys_sql_handle: "'||sys_sql_handle||'"');

  DBMS_OUTPUT.PUT_LINE('sys_plan_name: "'||sys_plan_name||'"');



  :plan_name := sys_plan_name;



  -- update description of new sql_plan_baseline

  description := UPPER('SQL_ID: '||TRIM('&&sql_id.')||' Plan Hash Value: '||TRIM('&&plan_hash_value.')||' created by coe_xfr_sql_baseline.sql');

  plans :=

  DBMS_SPM.ALTER_SQL_PLAN_BASELINE (

    sql_handle      => sys_sql_handle,

    plan_name       => sys_plan_name,

    attribute_name  => 'description',

    attribute_value => description );

  DBMS_OUTPUT.PUT_LINE(plans||' plan(s) modified description: "'||description||'"');



  DBMS_SQLTUNE.DROP_SQLSET(:ss_name);

  DBMS_OUTPUT.PUT_LINE('SQL tuning set '||:ss_name||' dropped.');

end;

/





-- display details of new sql_plan_baseline

SET ECHO ON;

REM

REM SQL Plan Baseline

REM ~~~~~~~~~~~~~~~~~

REM

SELECT signature, sql_handle, plan_name, enabled, accepted, fixed--, reproduced (avail on 11.2.0.2)

  FROM dba_sql_plan_baselines WHERE plan_name = :plan_name;



col description for a100

SELECT description

  FROM dba_sql_plan_baselines WHERE plan_name = :plan_name;

SET ECHO OFF;

PRO

SPO OFF;

WHENEVER SQLERROR CONTINUE;

SET DEF ON TERM ON ECHO OFF FEED 6 VER ON HEA ON LIN 80 PAGES 14 LONG 80 LONGC 80 TRIMS OFF TI OFF TIMI OFF SERVEROUT OFF NUM 10 SQLP SQL>;

SET SERVEROUT OFF;

UNDEFINE 1 2 sql_id plan_hash_value

CL COL

PRO

PRO coe_xfr_sql_baseline completed.

 

Thanks and Regards