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一次sql调优历程

kebo — Mon, 10 Sep 2007 11:35:00 GMT

在项目进入性能测试阶段，终于爆发了sql运行缓慢，系统吞吐量下降，甚至一度出现oracle服务器cpu100%的情况。具体开发和测试人员报告情况，开始介入处理。

具体查找性能缓慢的过程略除。
发现一条sql运行缓慢。通过跟踪发现一下信息
select alias_p2.pendingid, alias_p2.workitemid, alias_p2.operationid, alias_p2.operationkey,

2 alias_p2.title, alias_p2.sendercn, alias_p2.operatedes, alias_p2.pendingstate,

3 alias_p2.parameter, alias_p2.createdate, alias_p2.deptname, alias_p2.completeddate ,

4 alias_p2.openstate , alias_p2.name, alias_p2.processinstanceid, alias_p2.asset

5 from ( select alias_p1.pendingid, alias_p1.workitemid, alias_p1.operationid,

6 alias_p1.operationkey, alias_p1.title, alias_p1.sendercn, alias_p1.operatedes,

7 alias_p1.pendingstate, alias_p1.parameter, alias_p1.createdate, alias_p1.deptname,

8 alias_p1.completeddate , alias_p1.openstate , alias_p1.name, alias_p1.processinstanceid ,

9 alias_p1.asset , rownum rn from(select alias_p.pendingid, alias_p.workitemid, alias_p.operationid,

10 alias_p.operationkey, alias_p.title, alias_p.sendercn, alias_p.operatedes, alias_p.pendingstate,

11 alias_p.parameter, alias_p.createdate, alias_p.deptname, alias_p.completeddate , alias_p.openstate ,

12 pd.name, w.processinstanceid , eam_db.concatassetname( alias_p.operationkey, alias_p.operationid )

13 asset from WF_Pending alias_p, WF_WorkItem w, WF_ProcessDefinition pd, WF_ProcessInstance pi

14 where alias_p.ownerid='qinxue' and alias_p.pendingstate in(0,3,5,7,9,10,11,12)

15 and (alias_p.deptname=' 审控部信息处 ' or alias_p.deptname='' or alias_p.deptname is null)

16 and w.workitemid = alias_p.workitemid and pi.processinstanceid = w.processinstanceid

17 and pi.completeddate is null and pd.processdefinitionid = w.processdefinitionid order by alias_p.createdate desc) alias_p1 where rownum <=10)

alias_p2 where rn>=1;

已选择 10 行。

执行计划

----------------------------------------------------------

0 SELECT STATEMENT Optimizer=CHOOSE (Cost=10 Card=1 Bytes=2507

)

1 0 VIEW (Cost=10 Card=1 Bytes=2507)

2 1 COUNT (STOPKEY)

3 2 VIEW (Cost=10 Card=1 Bytes=2494)

4 3 SORT (ORDER BY STOPKEY) (Cost=10 Card=1 Bytes=167)

5 4 NESTED LOOPS (Cost=8 Card=1 Bytes=167)

6 5 NESTED LOOPS (Cost=7 Card=1 Bytes=162)

7 6 NESTED LOOPS (Cost=6 Card=1 Bytes=134)

8 7 TABLE ACCESS (FULL) OF 'WF_PENDING' (Cost=5

Card=1 Bytes=111)

9 7 TABLE ACCESS (BY INDEX ROWID) OF 'WF_WORKITE

M' (Cost=1 Card=3 Bytes=69)

10 9 INDEX (UNIQUE SCAN) OF 'SYS_C003694' (UNIQ

UE)

11 6 TABLE ACCESS (BY INDEX ROWID) OF 'WF_PROCESSDE

FINITION' (Cost=1 Card=1 Bytes=28)

12 11 INDEX (UNIQUE SCAN) OF 'SYS_C003684' (UNIQUE

)

13 5 TABLE ACCESS (BY INDEX ROWID) OF 'WF_PROCESSINST

ANCE' (Cost=1 Card=1 Bytes=5)

14 13 INDEX (UNIQUE SCAN) OF 'SYS_C003662' (UNIQUE)

统计信息

----------------------------------------------------------

314 recursive calls

0 db block gets

29433 consistent gets

0 physical reads

0 redo size

2153 bytes sent via SQL*Net to client

372 bytes received via SQL*Net from client

2 SQL*Net roundtrips to/from client

101 sorts (memory)

0 sorts (disk)

10 rows processed

其中一致读达到近3万次，关联调用出现314次。排序数值也非常多，显然第一目标是把这两个数据降下来。
通过进一步的分析。发现出现这些问题的主要原因是调用eam_db.concatassetname( alias_p.operationkey, alias_p.operationid )这个包。
开始考虑直接在sql外层做关联，不用function来实现。利用聚集函数来合并数据。
着手建立：

聚集函数： CREATE OR REPLACE FUNCTION F_ASSETLINK(P_STR VARCHAR2) RETURN VARCHAR2
AGGREGATE USING asset_link;

----------------------
创建type：CREATE OR REPLACE TYPE ASSET_LINK AS OBJECT (
STR VARCHAR2(30000),
STATIC FUNCTION ODCIAGGREGATEINITIALIZE(SCTX IN OUT ASSET_LINK) RETURN NUMBER,
MEMBER FUNCTION ODCIAGGREGATEITERATE(SELF IN OUT ASSET_LINK, VALUE IN VARCHAR2) RETURN NUMBER,
MEMBER FUNCTION ODCIAGGREGATETERMINATE(SELF IN ASSET_LINK, RETURNVALUE OUT VARCHAR2, FLAGS IN NUMBER) RETURN NUMBER,
MEMBER FUNCTION ODCIAGGREGATEMERGE(SELF IN OUT ASSET_LINK, CTX2 IN ASSET_LINK) RETURN NUMBER
)
------------------------------------------------------

创建type body：CREATE OR REPLACE TYPE BODY ASSET_LINK IS
STATIC FUNCTION ODCIAGGREGATEINITIALIZE(SCTX IN OUT ASSET_LINK) RETURN NUMBER IS
BEGIN
SCTX := ASSET_LINK(NULL);
RETURN ODCICONST.SUCCESS;
END;
MEMBER FUNCTION ODCIAGGREGATEITERATE(SELF IN OUT ASSET_LINK, VALUE IN VARCHAR2) RETURN NUMBER IS
BEGIN
SELF.STR := SELF.STR ||','|| VALUE;
RETURN ODCICONST.SUCCESS;
END;
MEMBER FUNCTION ODCIAGGREGATETERMINATE(SELF IN ASSET_LINK, RETURNVALUE OUT VARCHAR2, FLAGS IN NUMBER) RETURN NUMBER IS
BEGIN
RETURNVALUE := SELF.STR;
RETURN ODCICONST.SUCCESS;
END;
MEMBER FUNCTION ODCIAGGREGATEMERGE(SELF IN OUT ASSET_LINK, CTX2 IN ASSET_LINK) RETURN NUMBER IS
BEGIN
NULL;
RETURN ODCICONST.SUCCESS;
END;
END;
调整sql如下：
select alias_p.pendingid, alias_p.workitemid, alias_p.operationid,
   alias_p.operationkey, alias_p.title, alias_p.sendercn, alias_p.operatedes, alias_p.pendingstate,
   alias_p.parameter, alias_p.createdate, alias_p.deptname, alias_p.completeddate , alias_p.openstate ,
   pd.name, w.processinstanceid
   --,T.ASSETCLASS3 ASSET
   ,f_assetlink(d3.typename) ASSET
   --,eam_db.concatassetname( alias_p.operationkey, alias_p.operationid ) asset
   from WF_Pending alias_p, WF_WorkItem w,
   WF_ProcessDefinition pd, WF_ProcessInstance pi
   , tb_asset_dizhiyihao T,dic_app_wfconfig wfc,dic_app_assettype3 d3
   where alias_p.ownerid='qinxue'
   and alias_p.pendingstate in(0,3,5,7,9,10,11,12)
   and (alias_p.deptname='审控部信息处' or alias_p.deptname='' or alias_p.deptname is null)
   and w.workitemid = alias_p.workitemid
   and pi.processinstanceid = w.processinstanceid
   and pi.completeddate is null
   and pd.processdefinitionid = w.processdefinitionid
   AND    t.pk_businessid = alias_p.operationid
          and alias_p.operationkey = wfc.memo_1
          and wfc.wfconfig_code = t.wfconfig_code
   and t.assetclass3 = d3.assettype3_id
   group by alias_p.pendingid, alias_p.workitemid, alias_p.operationid,
   alias_p.operationkey, alias_p.title, alias_p.sendercn, alias_p.operatedes, alias_p.pendingstate,
   alias_p.parameter, alias_p.createdate, alias_p.deptname, alias_p.completeddate , alias_p.openstate ,
   pd.name, w.processinstanceid
   order by alias_p.createdate desc
得到统计数据如下：
C:\Documents and Settings\ibm>sqlplus /nolog

SQL*Plus: Release 10.2.0.1.0 - Production on 星期一 9月 10 19:27:33 2007

SQL> conn jic/jic@name
已连接。
SQL> set autotrace traceonly
SQL> select alias_p.pendingid, alias_p.workitemid, alias_p.operationid,
2     alias_p.operationkey, alias_p.title, alias_p.sendercn, alias_p.operatedes, alias_p.pendingstate,
3     alias_p.parameter, alias_p.createdate, alias_p.deptname, alias_p.completeddate , alias_p.openstate ,
4     pd.name, w.processinstanceid
5     --,T.ASSETCLASS3 ASSET
6     ,f_assetlink(d3.typename) ASSET
7     --,eam_db.concatassetname( alias_p.operationkey, alias_p.operationid ) asset
8     from WF_Pending alias_p, WF_WorkItem w,
9     WF_ProcessDefinition pd, WF_ProcessInstance pi
10     , tb_asset_dizhiyihao T,dic_app_wfconfig wfc,dic_app_assettype3 d3
11     where alias_p.ownerid='qinxue'
12     and alias_p.pendingstate in(0,3,5,7,9,10,11,12)
13     and (alias_p.deptname='审控部信息处' or alias_p.deptname='' or alias_p.deptname is null)
14     and w.workitemid = alias_p.workitemid
15     and pi.processinstanceid = w.processinstanceid
16     and pi.completeddate is null
17     and pd.processdefinitionid = w.processdefinitionid
18     AND    t.pk_businessid = alias_p.operationid
19            and alias_p.operationkey = wfc.memo_1
20            and wfc.wfconfig_code = t.wfconfig_code
21     and t.assetclass3 = d3.assettype3_id
22     group by alias_p.pendingid, alias_p.workitemid, alias_p.operationid,
23     alias_p.operationkey, alias_p.title, alias_p.sendercn, alias_p.operatedes, alias_p.pendingstate,
24     alias_p.parameter, alias_p.createdate, alias_p.deptname, alias_p.completeddate , alias_p.openstate ,
25     pd.name, w.processinstanceid
26     order by alias_p.createdate desc;

已选择30行。

执行计划
----------------------------------------------------------
   0      SELECT STATEMENT Optimizer=CHOOSE (Cost=19 Card=1 Bytes=205)
   1    0   SORT (GROUP BY) (Cost=19 Card=1 Bytes=205)
   2    1     NESTED LOOPS (Cost=17 Card=1 Bytes=205)
   3    2       HASH JOIN (Cost=16 Card=1 Bytes=191)
   4    3         HASH JOIN (Cost=11 Card=1 Bytes=183)
   5    4           NESTED LOOPS (Cost=8 Card=1 Bytes=167)
   6    5             NESTED LOOPS (Cost=7 Card=1 Bytes=139)
   7    6               NESTED LOOPS (Cost=6 Card=1 Bytes=134)
   8    7                 TABLE ACCESS (FULL) OF 'WF_PENDING' (Cost=5
          Card=1 Bytes=111)

9 7 TABLE ACCESS (BY INDEX ROWID) OF 'WF_WORKITE
M' (Cost=1 Card=1 Bytes=23)

10 9 INDEX (UNIQUE SCAN) OF 'SYS_C004347' (UNIQ
UE)

11 6 TABLE ACCESS (BY INDEX ROWID) OF 'WF_PROCESSIN
STANCE' (Cost=1 Card=1 Bytes=5)

12 11 INDEX (UNIQUE SCAN) OF 'SYS_C004334' (UNIQUE
)

13 5 TABLE ACCESS (BY INDEX ROWID) OF 'WF_PROCESSDEFI
NITION' (Cost=1 Card=1 Bytes=28)

14   13               INDEX (UNIQUE SCAN) OF 'SYS_C004329' (UNIQUE)
15    4           TABLE ACCESS (FULL) OF 'DIC_APP_WFCONFIG' (Cost=2
          Card=24 Bytes=384)

16 3 TABLE ACCESS (FULL) OF 'TB_ASSET_DIZHIYIHAO' (Cost=4
Card=310 Bytes=2480)

17 2 TABLE ACCESS (BY INDEX ROWID) OF 'DIC_APP_ASSETTYPE3'
(Cost=1 Card=1 Bytes=14)

18 17 INDEX (UNIQUE SCAN) OF 'PK_DIC_APP_ASSETTYPE3' (UNIQ
UE)

统计信息
----------------------------------------------------------
          6 recursive calls
          0 db block gets
        847 consistent gets
          0 physical reads
          0 redo size
       4102 bytes sent via SQL*Net to client
        383 bytes received via SQL*Net from client
          3 SQL*Net roundtrips to/from client
          1 sorts (memory)
          0 sorts (disk)

其中排序由101变为1次
一致读降为847。下降非常客观
关联调用仅有6次。
此sql性能优化非常可观。至此优化结束：)

kebo 2007-09-10 19:35 发表评论

分析函数一例

kebo — Tue, 17 Jul 2007 08:55:00 GMT

select z.a,z.b,z.c from (select lag(t.a,2)over(order by t.a) pp_val, lag(t.a,1)over(order by t.a) p_val, t.a, lead(t.a,1)over(order by t.a) n_val, lead(t.a,2)over(order by t.a) nn_val, t.b,t.c from test2 t) z where z.a = '1' and ((z.p_val = '1' and z.pp_val = '1') or (z.p_val = '1' and z.n_val = '1') or (z.n_val = '1' and z.nn_val = '1'));

kebo 2007-07-17 16:55 发表评论

夜读tom感悟

kebo — Tue, 10 Jul 2007 16:15:00 GMT

查询结果xml化： select dbms_xmlquery.getXML(' select * from test')from dual; 表的历史记录：执行：begin dbms_wm.enableversioning('tablename','VIEW_WO_OVERWRITE') 则对这个表的cud操作都会记录历史，这个在系统中做历史再好不过了。还有终于被tom说明：分析函数原来就是矩阵运算，呵呵，终于知道这类函数的数学原理了，呵呵，真爽，总算知道怎么理解了。还有宝贝儿遇到新项目，需要很深的会计知识了，还被老板乱说，导致不好工作，希望她不要烦恼，开心工作

kebo 2007-07-11 00:15 发表评论

sqlplus执行@sql.sql的错误

kebo — Wed, 27 Dec 2006 14:24:00 GMT

今天给数据库执行@spcreate.sql老是出
SP2-0734:unknown command beginning "spcreate.s..." - rest of line ignored.
郁闷坏了。经过一番折腾原来是
solution Description:
=====================
You need to enter a valid SQL*Plus command.
In this case, you cannot start svrmgrl from within SQL*Plus,
you have to start svrmgrl from the command prompt.
This error will also occur when trying to execute a
the @ symbol is mapped to the key 'Kill' from the user's keyboard.
The way to find out the current keyboard mapping in a unix environment is using the command 'stty -a'.
The way to correct problem is to map 'Kill' to some other keyboard symbol.
The command example would be 'stty kill ^U'.
Having remapped the key you would then log into SQL*Plus and execute script.
-------------------------------纪念一下
如果出现空行报错的话记得执行:
SET SQLBLANKLINES ON

kebo 2006-12-27 22:24 发表评论

听oracle讲座感受

kebo — Mon, 02 Oct 2006 17:43:00 GMT

今天听了下oracle讲座,一个感受，以后不敢操作数据库了，发现对大多数数据库命令产生的后果和影响都不是很清楚。想起以前切换双机

的时候也出现eygle说的问题，然来真的对数据库基础知识预备不足啊。感觉以前真是可以称为“虎胆”哦。难怪老幕以前佩服我！！！卡卡卡。

恩，感觉oracle入门现在都够不上，不敢再给别人解决问题:)免得惹笑话。梳理了一下，估计也就对sql,集合的理解熟悉点，有点把我哦。低

调，低调......学习学习......

kebo 2006-10-03 01:43 发表评论

aix 设置 ip需要注意的地方

kebo — Fri, 14 Apr 2006 07:06:00 GMT

　这几天很郁闷，公司弄来一台IBM小机．让我装系统．在公司的时候用DHCP给分配ＩＰ,安装好系统和oracle后，拉到现场设置静态ip后就是无法联网
ip怎么设置也不正确。经检查网线和交换机都是正常的。同样的ip和网线用本是没有任何问题的。最后只好找公司的主机工程师来调试了。来了也是设置半天也没有成功，当中还问过ibm的工程师，也没有搞定。哎，把我们俩给郁闷的。最后同事找了一个朋友问，一步一步地做，才发现经过DHCP后在按一般的步骤设置是不可以的，必须重新设置网卡的状态，设置ip后重起（？）。经过3个多小时的折腾，网络终于调试正常。记blog，留为纪念

kebo 2006-04-14 15:06 发表评论

sql

kebo — Wed, 29 Mar 2006 05:41:00 GMT

(转)

-- 逻辑读多的SQL
select * from (select buffer_gets, sql_text
from v$sqlarea
where buffer_gets > 500000
order by buffer_gets desc) where rownum<=30;

-- 执行次数多的SQL
select sql_text,executions from
(select sql_text,executions from v$sqlarea order by executions desc)
where rownum<81;

-- 读硬盘多的SQL
select sql_text,disk_reads from
(select sql_text,disk_reads from v$sqlarea order by disk_reads desc)
where rownum<21;

-- 排序多的SQL
select sql_text,sorts from
(select sql_text,sorts from v$sqlarea order by sorts desc)
where rownum<21;

--分析的次数太多，执行的次数太少，要用绑变量的方法来写sql
set pagesize 600;
set linesize 120;
select substr(sql_text,1,80) "sql", count(*), sum(executions) "totexecs"
from v$sqlarea
where executions < 5
group by substr(sql_text,1,80)
having count(*) > 30
order by 2;

kebo 2006-03-29 13:41 发表评论

oracle分页的一种写法

kebo — Mon, 30 Jan 2006 04:00:00 GMT

SELECT * FROM ( SELECT row_.*, rownum rownum_ FROM (...... ) row_ WHERE rownum <= ?) WHERE rownum_ > ?

kebo 2006-01-30 12:00 发表评论

人生不如意十有八九

kebo — Sun, 08 Jan 2006 01:33:00 GMT

今天要去给数据库装Partition组件，下一个晚上的oracle，不想机器自动重启了。早上听到硬盘没有响，以为下完了。在床上挺高兴的，可是一看确实机器重启过，没有下了，只下了很少一点点，埃，郁闷的我，今天必须做完这个，不然明天就不能用了，问题大了，唉，没办法接着下吧。今天晚上估计又要很晚了。不如意十有八九啊！，不说了，赶快写好方案步骤，去了就快做，希望不要出现意外了，这个系统已经折腾很久了，每次做的时候总会出现一些个么蛾子的问题，让人措手不急。

kebo 2006-01-08 09:33 发表评论