一次sql调优历程

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：)

posted on 2007-09-10 19:35 kebo 阅读(461) 评论(0) 编辑收藏所属分类: oracle

常用链接

留言簿(1)

随笔分类

随笔档案

文章档案

相册

收藏夹

朋友

搜索

积分与排名

最新评论

阅读排行榜

评论排行榜


只有注册用户登录后才能发表评论。




网站导航: 博客园 IT新闻知识库 C++博客博问管理
相关文章: 一个sql写法一次sql调优历程分析函数一例夜读tom感悟 sqlplus执行@sql.sql的错误听oracle讲座感受 aix 设置 ip需要注意的地方 sql oracle分页的一种写法人生不如意十有八九