<---------创建一个xml文件，叫做a1.xml
a1.xml:
<?xml version="1.0" encoding="UTF-8"?>
<OPTPROFILE VERSION="9.1.0.0">
<STMTPROFILE ID="Use Table Scan instead of Index Scan">
<STMTKEY SCHEMA="TAOEWANG">
<![CDATA[SELECT * FROM TAOEWANG.MYTABLE WHERE ID < 1000]]>
</STMTKEY>
<OPTGUIDELINES>
<TBSCAN TABLE="TAOEWANG.MYTABLE"/>
</OPTGUIDELINES>
</STMTPROFILE>
</OPTPROFILE>
<----------创建一个del文件,叫insert.del
insert .del:
"TAOEWANG", "PROF1", "a1.xml"
<--------用import把xml插入profile系统表
D:\TEMP>db2 import from insert.del of del modified by lobsinfile insert into systools.opt_profile
SQL3109N The utility is beginning to load data from file "insert.del".
SQL3110N The utility has completed processing. "1" rows were read from the
input file.
SQL3221W ...Begin COMMIT WORK. Input Record Count = "1".
SQL3222W ...COMMIT of any database changes was successful.
SQL3149N "1" rows were processed from the input file. "1" rows weresuccessfully inserted into the table. "0" rows were rejected.
Number of rows read = 1
Number of rows skipped = 0
Number of rows inserted = 1
Number of rows updated = 0
Number of rows rejected = 0
Number of rows committed = 1
<--------设置db2set env variable打开profile
D:\TEMP>db2set DB2_OPTPROFILE=YES
<--------重起实例让db2set生效
D:\TEMP>db2stop force
12/27/2007 08:54:45 0 0 SQL1064N DB2STOP processing was successful.
SQL1064N DB2STOP processing was successful.
D:\TEMP>db2start
12/27/2007 08:54:48 0 0 SQL1063N DB2START processing was successful.
SQL1063N DB2START processing was successful.
D:\TEMP>db2 connect to SAMPEL2
Database Connection Information
Database server = DB2/NT 9.1.0
SQL authorization ID = TAOEWANG
Local database alias = SAMPEL2
D:\TEMP>db2 set current explain mode explain
DB20000I The SQL command completed successfully.
D:\TEMP>db2 set current schema taoewang
DB20000I The SQL command completed successfully.
<---------设置需要使用的profile
D:\TEMP>db2 set current optimization profile='PROF1'
DB20000I The SQL command completed successfully.
D:\TEMP>db2 "SELECT * FROM TAOEWANG.MYTABLE WHERE ID < 1000"
SQL0217W The statement was not executed as only Explain information requests
are being processed. SQLSTATE=01604
D:\TEMP>db2 set current explain mode no
DB20000I The SQL command completed successfully.
D:\TEMP>db2exfmt -d sampel2 -g TIC -w -1 -n % -s % -# 0 -o output2.txt
DB2 Universal Database Version 9.1, 5622-044 (c) Copyright IBM Corp. 1991, 2006
Licensed Material - Program Property of IBM
IBM DATABASE 2 Explain Table Format Tool
Connecting to the Database.
Connect to Database Successful.
Output is in output2.txt.
Executing Connect Reset -- Connect Reset was Successful.
<------现在用了tablescan了
D:\TEMP>uedit32 output2.txt
Profile Information:
--------------------
OPT_PROF: (Optimization Profile Name)
TAOEWANG.PROF1
STMTPROF: (Statement Profile Name)
Use Table Scan instead of Index Scan
Original Statement:
------------------
SELECT *
FROM TAOEWANG.MYTABLE
WHERE ID < 1000
Optimized Statement:
-------------------
SELECT Q1.NAME AS "NAME", Q1.ID AS "ID", Q1.SALARY AS "SALARY", Q1.PHONE AS
"PHONE"
FROM TAOEWANG.MYTABLE AS Q1
WHERE (Q1.ID < 1000)
Access Plan:
-----------
Total Cost: 7.56912
Query Degree: 1
Rows
RETURN
( 1)
Cost
I/O
|
1
TBSCAN
( 2)
7.56912
1
|
4
TABLE: TAOEWANG
MYTABLE
Extended Diagnostic Information:
--------------------------------
No extended Diagnostic Information for this statment.
如果用户希望在应用程序里面使用profile,可以使用下面的几种方法之一
对于cli应用程序中使用EXEC SQL SET CURRENT OPTIMIZATION PROFILE = 'xxxxxxxxx';
也可以在db2cli.ini中指定CURRENTOPTIMIZATIONPROFILE='"SCHEMA"."PROFILE"'
对于stored procedure在bind的时候指定OPTPROFILE
再次强调,profile不是功能较多药,只是止痛药~~~只有在万不得已的情况下才应该使用profile暂时指定用户需要的操作.一般来说,对于优化器问题用户应该尽量找到root cause,而不是简单地指定一个profile了事~~~
