蓝的成长记——追逐DBA(8):重拾SP报告,回忆oracle的STATSPACK实验

***********************************************声明*********************************************************************** 

原创作品,出自 “深蓝的blog” 博客,欢迎转载,转载时请务必注明出处,否则追究版权法律责任。

深蓝的blog:http://blog.csdn.net/huangyanlong/article/details/39803995

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蓝的成长记——追逐DBA(8):重拾SP报告,回忆oracle的STATSPACK实验

**************************************************简介********************************************************************

        个人在oracle路上的成长记录,其中以蓝自喻,分享成长中的情感、眼界与技术的变化与成长。敏感信息均以英文形式代替,不会泄露任何企业机密,纯为技术分享。

        创作灵感源于对自己的自省和记录。若能对刚刚起步的库友起到些许的帮助或共鸣,欣慰不已。

        欢迎拍砖,如有关技术细节表述有错误之处,请您留言或邮件(hyldba@163.com)指明,不胜感激。

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今天有些慵懒,整理过往学习中的一个实验,忆起oracle的SP报告。

                                                              ——深蓝

**************************************************前言********************************************************************

这是一部个人记录的成长杂记,既然步入到oracle的这片蓝海,免不了一路的奔波与不断的考验。借由此杂记与库友们分享蓝的成长历程。

不知何时起对蓝有了一种说不出来的痴迷,痴迷其广博,痴迷其深邃,痴迷于近在咫尺却又遥不可及。

而又说不清从何时起,注视于oracle的红色耀眼,照亮出眼前的一道光,未知与迷惑在自己的脚下开始初露些许人生的充实与青春的回馈。

在追逐于DBA梦想的道路上步步前行。

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    时间有些久了,有些淡忘了SP报告的方法了,今天就利用闲暇的时光,重新拾起熟悉又陌生的STATSPACK报告的实验。

实验计划:

1、模拟某业务环境,制定快照计划;

2、生成初始状态数据库的statspack报告,分析数据;

3、调整数据缓冲区尺寸,生成 statspack报告,分析数据;

4、创建索引,生成statspack报告,分析数据;

5、使用绑定变量,生成 statspack报告,分析数据。

******************************************************************************************

步骤一:模拟业务环境,制定快照计划

目标:

1、关闭sga自动管理,调整DB cache、sharepool大小;             

2、部署statspack;             

3、部署模拟现场环境;

*****************************************************************************************

1、关闭sga自动管理,调整DB cache、sharepool大小,模拟现场环境

SQL> alter system set memory_target=0 scope=spfile;        --11g中关闭内存自动管理
SQL> alter system set sga_target=0;
SQL> alter system set db_cache_size=30m scope=spfile;      --修改DB cache大小
SQL> alter system set shared_pool_size=70m scope=spfile;   --修改share pool大小
SQL> startup force;                                        --重启数据库
SQL> select component,current_size/1024/1024 from v$sga_dynamic_components;  --查询修改后的缓冲区大小
COMPONENT                                          CURRENT_SIZE/1024/1024
----------------------------------------           ----------------------
shared pool                                                             72
DEFAULT buffer cache                                                    32

2、部署statspack

SQL> create tablespace tools datafile '/u01/app/oracle/oradata/PROD/disk6/tools01.dbf' size 300m;  --创建statspack专用的tools表空间
SQL> @?/rdbms/admin/spcreate.sql  --以sysdba身份执行spcreate脚本,用于创建spcreate对象
输入值设置:
Enter value for perfstat_password: oracle
Enter value for default_tablespace: tools
Enter value for temporary_tablespace:回车
$ vi /u01/app/oracle/product/11.2.0/db_1/rdbms/admin/spauto.sql  --设置自动快照时间,间隔30分钟生成一次快照
编辑如下:
begin
  select instance_number into :instno from v$instance;
  dbms_job.submit(:jobno, 'statspack.snap;', trunc(sysdate+1/48,'MI'), 'trunc(SYSDATE+1/48,''MI'')', TRUE, :instno);
  commit;
end;
SQL>exec statspack.modify_statspack_parameter(i_snap_level=>7);  --设置快照默认级别为7
SQL> conn scott/tiger
SQL>CREATE SEQUENCE emp2_empno   
  	INCREMENT BY 1
  	START WITH 1
  	MAXVALUE 100000000
  	CACHE 10000
  	NOCYCLE;  --执行创建序列语句

3、部署模拟现场环境

SQL> create table emp2 as select * from emp where 1=2; --创建实验表emp2,结构同emp表
SQL> alter table emp2 modify empno number(10); 
SQL> alter table emp2 modify ename varchar(30);
SQL> alter table emp2 nologging; --为加快数据插入速度,关闭日志记录
--插入2千万行数据
SQL>begin
     for i in 1..20000000 loop
       insert into emp2
       values (emp2_empno.nextval,'cuug'||i,'SALESMAN',7698,sysdate,1600,300,30);
       if mod(i,1000)=0 then 
       commit;
       end if;
    end loop;
    commit;
end;
/
SQL> alter table emp2 logging; --开启日志记录
$ vi script/bin/share_pool_sql_1.sh --编写查询的业务脚本
#!/bin/bash

CNT=1
while [ $CNT -lt 20000000 ]
do
sqlplus scott/tiger <<EOF
select * from emp2 where empno=$CNT;
exit
EOF
CNT=`expr $CNT + 1`
done
$ sh script/bin/share_pool_sql_1.sh  --执行脚本,模拟“查询业务”

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步骤二:生成原始statspack报告,分析报告

目标:

1、开启自动快照;             

2、生成、导出报告;             

3、关闭job;             

4、分析报告。

*****************************************************************************************

1、开启自动快照

<span style="font-size:12px;">SQL> conn perfstat/oracle    --开启快照及查询相关业务时,需要以perfstat身份登录
SQL>@?/rdbms/admin/spauto    --执行脚本,开启自动快照</span>

2、生成报告

SQL> alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss';  --设置查看格式,便于查询
SQL> select snap_id,snap_time,snap_level from stats$snapshot order by snap_time; --查询快照数量,是否满足生成statspack报告条件
SQL> @?/rdbms/admin/spreport  --生成statspack报告
手工设置:
Enter value for begin_snap:快照起点
Enter value for end_snap: 快照终点
Enter value for report_name:默认或指定报告名称
--使用x-manager将报告拷贝到windows主机

蓝的成长记——追逐DBA(8):重拾SP报告,回忆oracle的STATSPACK实验

3、关闭job

SQL> select job,log_user,last_date,next_date from user_jobs;  --查询需要关闭的job号
SQL> exec dbms_job.remove('21');                       --将job号为21的任务删除

4、分析报告

关注点:

①buffer hit

②library hit

③Top 5 Timed Events

④造成最大物理读的sql

⑤Buffer Pool Advisory

⑥time model system stats

⑦Latch Sleep breakdown

 

① buffer hit、②library hit

时间

Buffer  Hit(%)

Library Hit(%)

17:42:01~ 18:12:00

99.76

86.56

18:12:00 ~ 18:42:00

99.87

86.55

18:42:00~ 19:12:05

99.74

86.55

19:12:05~ 19:42:03

99.86

86.90

avg

99.81

86.64

分析:
buffer hit高于95%符合数据正常性能标准。library hit低于95%,说明库缓存区命中率较低,需做相应调整。

③Top 5 Timed Events

时间

name

waits

Time (s)

17:42:01~ 18:12:00

direct path read

32,014,645

814

db file sequential read

1,697

6

log file parallel write

706

5

18:12:00 ~18:42:00

direct path read

32,095,337

816

log file parallel write

898

5

os thread startup

50

9

18:42:00~ 19:12:05

direct path read

32,438,303

816

log file parallel write

816

7

control file parallel write

493

1

19:12:05~ 19:42:03

direct path read

32,255,547

816

log file parallel write

716

5

control file parallel write

491

1

分析:
    direct path read的磁盘I/O产生量最大,db file sequential read、log file parallel write、control file parallel write也会产生部分磁盘I/O。

④查出造成物理读最大的前几个sql语句,产生执行计划

SQL>select sql_text from v$sql where disk_reads=(select max(disk_reads) from v$sql);  --查询造成最大物理读的sql语句
……
select * from emp2 where empno=2215
select * from emp2 where empno=2270
select * from emp2 where empno=2208
……
SQL> set autotrace on;
SQL> set timing on;
SQL> select * from emp2 where empno=2208;  --执行一条语句,查看执行计划,可以发现方式为全表扫描,在oracle11g下全表扫描时,库缓冲区将直接从磁盘中查询数据,磁盘I/O较大。cost值、physical read较大
<span style="font-family:SimSun;font-size:12px;">   EMPNO     ENAME        JOB           MGR  HIREDATE     SAL   COMM  DEPTNO
------------ ---------------------   ------------------  ----------  -----------     ---------- ------------  --------------
      2208       cuug2207     SALESMAN    7698  03-JUN-14       1600     300        30
</span>Elapsed: 00:00:00.94
Execution Plan
----------------------------------------------------------
Plan hash value: 2941272003
--------------------------------------------------------------------------
| Id  | Operation         | Name | Rows  | Bytes | Cost (%CPU)| Time     |
--------------------------------------------------------------------------
|   0 | SELECT STATEMENT  |      |     1 |    48 | 40046   (1)| 00:08:01 |
|*  1 |  TABLE ACCESS FULL| EMP2 |     1 |    48 | 40046   (1)| 00:08:01 |
--------------------------------------------------------------------------
Statistics
----------------------------------------------------------
          0  recursive calls
          0  db block gets
     147357  consistent gets
     147349  physical reads
          0  redo size
        869  bytes sent via SQL*Net to client
        419  bytes received via SQL*Net from client
          2  SQL*Net roundtrips to/from client
          0  sorts (memory)
          0  sorts (disk)
          1  rows processed

 

分析:
未发现造成物理读最大的sql。但发现查询语句为全表扫描,每条语句物理读都相对较大。

⑤Buffer Pool Advisory

statistics

Time

P

Size for

Est (M)

Size

Factr

Buffers

(thousands)

Est

Phys

Read

Factr

Estimated

Phys Reads

(thousands)

Est Phys

Read Time

 

Est

% dbtime

for Rds

 

17:42:01~ 18:12:00

D

32

1.0

4

1.0

17

15

.3

18:12:00 ~18:42:00

D

32

1.0

4

1.0

18

18

.2

18:42:00~ 19:12:05

D

32

1.0

4

1.0

20

18

.2

19:12:05~ 19:42:03

D

32

1.0

4

1.0

21

18

.1

avg

 

32

1.0

4

1.0

19

17.25

.2

example

Time :17:42:01~ 18:12:00

                                   Est

                                  Phys      Estimated                   Est

    Size for  Size      Buffers   Read     Phys Reads     Est Phys % dbtime

P    Est (M) Factr  (thousands)  Factr    (thousands)    Read Time  for Rds

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

D          4    .1            0    1.2             21           20       .4

D          8    .3            1    1.1             19           17       .3

D         12    .4            1    1.1             18           16       .3

D         16    .5            2    1.0             18           16       .3

D         20    .6            2    1.0             18           15       .3

D         24    .8            3    1.0             17           15       .3

D         28    .9            3    1.0             17           15       .3

D        32   1.0            4    1.0             17           15       .3

D         36   1.1            4    1.0             17           15       .3

D         40   1.3            5    1.0             17           15       .3

D         44   1.4            5    1.0             17           15       .3

D         48   1.5            6    1.0             17           15       .3

D         52   1.6            6    1.0             17           15       .3

D         56   1.8            7    1.0             17           15       .3

D         60   1.9            7    1.0             17           15       .3

D         64   2.0            8    1.0             17           15       .3

 

分析:
对比4个时间段中的最佳buffer pool建议及第一时间段下的详细趋势列表,buffer pool设置为32m并未影响到性能。

⑥time model system stats

time:17:42:01~ 18:12:00

Statistic                                       Time (s) % DB time

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

sql execute elapsed time                         1,772.4      99.3

DB CPU                                           1,747.0      97.9

parse time elapsed                                  62.4       3.5

hard parse elapsed time                            58.0       3.3

connection management call elapsed                   6.2        .3

PL/SQL execution elapsed time                        6.1        .3

hard parse (sharing criteria) elaps                  6.1        .3

hard parse (bind mismatch) elapsed                   3.9        .2

PL/SQL compilation elapsed time                      0.7        .0

repeated bind elapsed time                           0.4        .0

sequence load elapsed time                           0.1        .0

DB time                                          1,784.9

background elapsed time                             26.5

background cpu time                                  3.7

time:18:12:00 ~18:42:00

Statistic                                       Time (s) % DB time

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

sql execute elapsed time                         2,549.1      99.5

DB CPU                                           1,752.4      68.4

parse time elapsed                                  60.2       2.4

hard parse elapsed time                            57.0       2.2

PL/SQL execution elapsed time                        6.2        .2

hard parse (sharing criteria) elaps                  6.2        .2

connection management call elapsed                   6.1        .2

hard parse (bind mismatch) elapsed                   4.0        .2

PL/SQL compilation elapsed time                      0.7        .0

repeated bind elapsed time                           0.4        .0

sequence load elapsed time                           0.1        .0

DB time                                          2,561.0

background elapsed time                             21.2

background cpu time                                  1.9

time:18:42:00~ 19:12:05

Statistic                                       Time (s) % DB time

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

sql execute elapsed time                         3,548.9      99.6

DB CPU                                           1,751.7      49.2

parse time elapsed                                  37.7       1.1

hard parse elapsed time                            34.9       1.0

connection management call elapsed                   7.3        .2

hard parse (sharing criteria) elaps                  3.6        .1

PL/SQL execution elapsed time                        3.2        .1

hard parse (bind mismatch) elapsed                   2.1        .1

PL/SQL compilation elapsed time                      0.5        .0

repeated bind elapsed time                           0.4        .0

sequence load elapsed time                           0.1        .0

DB time                                          3,563.0

background elapsed time                             30.8

background cpu time                                  3.7

time:19:12:05~ 19:42:03

Statistic                                       Time (s) % DB time

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

sql execute elapsed time                         3,541.3      99.7

DB CPU                                           1,746.9      49.2

parse time elapsed                                  37.9       1.1

hard parse elapsed time                            35.2       1.0

connection management call elapsed                   5.3        .2

hard parse (sharing criteria) elaps                  3.7        .1

PL/SQL execution elapsed time                        3.2        .1

hard parse (bind mismatch) elapsed                   2.0        .1

PL/SQL compilation elapsed time                      0.4        .0

repeated bind elapsed time                           0.3        .0

sequence load elapsed time                           0.1        .0

DB time                                          3,552.3

background elapsed time                             22.0

background cpu time                                  1.4

分析:
对比4个时间段的time model system stats,发现有硬解析存在。

⑦Latch Sleep breakdown

time:17:42:01~ 18:12:00

                                       Get                                 Spin

Latch Name                        Requests       Misses      Sleeps        Gets

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

qmn task queue latch                   252           11          11           0

shared pool                        669,111            7           7           0

space background task latc           1,114            6           6           0

cache buffers chains             1,415,617            1           1           0

JS Sh mem access                         4            1           1           0

OS process allocation                4,354            1           1           0

FOB s.o list latch                   7,177            1           1           0

messages                            16,597            1           1           0

In memory undo latch                60,562            1           1           0

time:18:12:00 ~18:42:00

                                       Get                                 Spin

Latch Name                        Requests       Misses      Sleeps        Gets

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

qmn task queue latch                   260           13          13           0

space background task latc           1,109            4           4           0

SQL memory manager latch             3,316            1           1           0

JS Sh mem access                         5            1           1           0

FOB s.o list latch                   7,103            1           1           0

shared pool                        666,763            1           1           0

time:18:42:00~ 19:12:05

                                       Get                                 Spin

Latch Name                        Requests       Misses      Sleeps        Gets

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

qmn task queue latch                   256           10          10           0

space background task latc           1,125            7           7           0

JS Sh mem access                         6            2           2           0

shared pool                       657,424            1           1           0

time:19:12:05~ 19:42:03

                                       Get                                 Spin

Latch Name                        Requests       Misses      Sleeps        Gets

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

qmn task queue latch                   256           10          10           0

space background task latc           1,109            5           5           0

JS Sh mem access                         3            1           1           0

分析:
观察Latch Sleep breakdown,在4个时间段中出现有miss、sleep的次数没有明显突显趋势,对性能没产生根本性影响。

总结:

通过以上几点分析发现,影响性能的方面有:
① library hit 平均值为86.64%低于标准值95%;
② direct path read产生磁盘I/O量最大,生成执行计划后发现,查询数据的方式是全表扫描;
③ time model system stats信息显示出,业务中存在一定量的hard parse。

*****************************************************************************************

步骤三:调整数据缓冲区尺寸,生成statspack报告,分析数据

思路:

通过初始报告分析,需提高库缓冲区的命中率及加索引以改变全表扫描的查询方式。而加入索          

引后,对于数据的查询,会由目前直接从磁盘读取变为通过数据缓冲区读取,I/O性能会得到提          

高。会对数据缓冲区有一定要求,目前数据缓冲区设为32m,由于查询业务是通过全表扫描方式,          

未能体现出缓冲区大小是否对性能有影响,但发现由于目前可分配内存资源较多,先将其调整          

为64m,观察是否会对性能有影响,为之后继续调优做准备。

目标:

1、调整缓冲区尺寸;             

2、生成statspack报告;              

3、分析报告

*****************************************************************************************

1、调整缓冲区尺寸

SQL> alter system set db_cache_size=64m;

2、生成statspack报告

SQL> @?/rdbms/admin/spreport               --重新生成statspack分析报告

3、分析报告

关注点:

①buffer hit

②library hit

③Top 5 Timed Events

④造成最大物理读的sql

⑤Buffer Pool Advisory

⑥time model system stats

⑦Latch Sleep breakdown

 

① buffer hit、②library hit

时间

Buffer  Hit(%)

Library Hit(%)

05:52:00 ~ 06:22:03

99.99

86.34

06:22:03 ~ 06:52:02

99.96

86.73

06:52:02 ~ 07:22:01

99.99

86.34

07:22:01 ~ 07:52:04

100.00

86.56

avg

99.99

86.49

分析:
    buffer hit由之前平均99.81提升为99.99%,性能还是有一定的提升。library hit平均为86.49%与之前平均86.64%没有显著变化,依然低于95%,说明库缓存区命中率仍然较低,需做进一步调整。

③Top 5 Timed Events

时间

name

waits

Time (s)

05:52:00 ~06:22:03

direct path read

17,621,085

750

log file parallel write

694

1

control file parallel write

523

1

06:22:03 ~06:52:02

direct path read

17,661,174

754

log file parallel write

422

1

control file parallel write

523

1

06:52:02 ~ 07:22:01

direct path read

17,596,117

752

log file parallel write

534

1

control file parallel write

522

1

07:22:01 ~ 07:52:04

direct path read

17,644,217

754

log file parallel write

440

1

control file parallel write

524

1

avg

direct path read

17,630,648

 

分析:
    虽然direct path read的磁盘I/O产生量仍然为最大,但是数据比较于未调整缓冲区大小之前,由平均32,438,303下降为17,630,648,仍是有显著改善的。log file parallel write、control file parallel write仍会产生部分磁盘I/O。由此,可通过全表扫描的I/O等待事件高,预判出需要在经常访问的列上加索引,以通过减少磁盘I/O产生量最大的事件的I/O来降低磁盘的I/O,进而提升性能。

④查出造成物理读最大的前几个sql语句,产生执行计划

SQL>select sql_text from v$sql where disk_reads=(select max(disk_reads) from v$sql);  --查询造成最大物理读的sql语句
……
select * from emp2 where empno=4009
select * from emp2 where empno=4012
select * from emp2 where empno=4023
……
SQL> set autotrace on;
SQL> set timing on;
SQL> select * from emp2 where empno=4009;  --执行一条语句,查看执行计划,可以发现方式为全表扫描,磁盘I/O较大。cost值、physical read较大
<span style="font-size:12px;">   EMPNO     ENAME        JOB           MGR  HIREDATE     SAL   COMM  DEPTNO
------------ ---------------------   ------------------  ----------  -----------     ---------- ------------  --------------
      4009 cuug4008             SALESMAN        7698 03-JUN-14       1600        300         30
</span>Elapsed: 00:00:00.94
Execution Plan
----------------------------------------------------------
Plan hash value: 2941272003
--------------------------------------------------------------------------
| Id  | Operation         | Name | Rows  | Bytes | Cost (%CPU)| Time     |
--------------------------------------------------------------------------
|   0 | SELECT STATEMENT  |      |     1 |    48 | 40046   (1)| 00:08:01 |
|*  1 |  TABLE ACCESS FULL| EMP2 |     1 |    48 | 40046   (1)| 00:08:01 |
--------------------------------------------------------------------------
Statistics
----------------------------------------------------------
          0  recursive calls
          0  db block gets
     147357  consistent gets
     147349  physical reads
          0  redo size
        869  bytes sent via SQL*Net to client
        419  bytes received via SQL*Net from client
          2  SQL*Net roundtrips to/from client
          0  sorts (memory)
          0  sorts (disk)
          1  rows processed

 

分析:
未发现造成物理读最大的sql。但发现查询语句为全表扫描,每条语句物理读都相对较大,预判需对该表添加索引。

⑤Buffer Pool Advisory

statistics

Time

P

Size for

Est (M)

Size

Factr

Buffers

(thousands)

Est

Phys

Read

Factr

Estimated

Phys Reads

(thousands)

Est Phys

Read Time

 

Est

% dbtime

for Rds

 

05:52:00 ~06:22:03

D

64

1.0

8

1.0

10

7

.0

06:22:03 ~06:52:02

D

64

1.0

8

1.0

10

7

.0

06:22:03 ~06:52:02

D

64

1.0

8

1.0

10

7

.0

07:22:01 ~ 07:52:04

D

64

1.0

4

1.0

10

7

.0

avg(now)

 

64

1.0

6

1.0

10

7

.0

avg (last)

 

32

1.0

4

1.0

19

17.25

.2

example

Time : 05:52:00 ~06:22:03

                                   Est

                                  Phys      Estimated                   Est

    Size for  Size      Buffers   Read     Phys Reads     Est Phys % dbtime

P    Est (M) Factr  (thousands)  Factr    (thousands)    Read Time  for Rds

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

D          4    .1            0   31.1            300          206      1.0

D          8    .1            1   14.4            139           95       .5

D         12    .2            1    6.5             62           43       .2

D         16    .3            2    4.4             43           29       .1

D         20    .3            2    3.0             29           20       .1

D         24    .4            3    2.4             23           16       .1

D         28    .4            3    1.8             17           12       .1

D         32    .5            4    1.7             16           11       .1

D         36    .6            4    1.5             15           10       .1

D         40    .6            5    1.3             13            9       .0

D         44    .7            5    1.0             10            7       .0

D         48    .8            6    1.0             10            7       .0

D         52    .8            6    1.0             10            7       .0

D         56    .9            7    1.0             10            7       .0

D         60    .9            7    1.0             10            7       .0

D        64   1.0            8    1.0             10            7       .0

D         68   1.1            8    1.0             10            7       .0

D         72   1.1            9    1.0             10            7       .0

D         76   1.2            9    1.0             10            7       .0

D         80   1.3           10    1.0             10            7       .0

分析:
对比4个时间段中的最佳buffer pool建议,再与未调整缓冲区之前比较,虽然最佳尺寸设置建议均为人为指定的值(第一次为32m、第二次为64m)。但当缓冲区由32m调高到64m时,缓冲区的使用平均由4000升高到6000,预估的物理读由之前平均为19000降低到10000,预估的物理读时间由原来的平均17.25降低到7。通过物理读的下降,发现将缓冲区调大,对I/O性能有明显的改善。

⑥time model system stats

time:05:52:00 ~06:22:03

Statistic                                       Time (s) % DB time

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

sql execute elapsed time                         1,767.9      99.3

DB CPU                                           1,751.9      98.4

parse time elapsed                                  56.9       3.2

hard parse elapsed time                            53.4       3.0

hard parse (sharing criteria) elaps                  6.8        .4

connection management call elapsed                   6.6        .4

PL/SQL execution elapsed time                        5.9        .3

hard parse (bind mismatch) elapsed                   3.9        .2

PL/SQL compilation elapsed time                      0.6        .0

repeated bind elapsed time                           0.4        .0

sequence load elapsed time                           0.1        .0

DB time                                          1,780.4

background elapsed time                             12.4

background cpu time                                  1.6

time:06:22:03 ~06:52:02

Statistic                                       Time (s) % DB time

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

sql execute elapsed time                         1,756.0      99.2

DB CPU                                           1,749.6      98.9

parse time elapsed                                  48.7       2.8

hard parse elapsed time                            45.0       2.5

connection management call elapsed                   6.4        .4

hard parse (sharing criteria) elaps                  6.0        .3

PL/SQL execution elapsed time                        5.5        .3

hard parse (bind mismatch) elapsed                   4.3        .2

PL/SQL compilation elapsed time                      0.8        .0

repeated bind elapsed time                           0.4        .0

sequence load elapsed time                           0.1        .0

DB time                                          1,769.8

background elapsed time                             10.8

background cpu time                                  1.6

time:06:52:02~07:22:01

Statistic                                       Time (s) % DB time

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

sql execute elapsed time                         1,755.9      99.3

DB CPU                                           1,745.2      98.7

parse time elapsed                                  49.7       2.8

hard parse elapsed time                            45.7       2.6

connection management call elapsed                   7.3        .4

PL/SQL execution elapsed time                        6.1        .3

hard parse (sharing criteria) elaps                  6.1        .3

hard parse (bind mismatch) elapsed                   3.5        .2

PL/SQL compilation elapsed time                      1.4        .1

repeated bind elapsed time                           0.5        .0

sequence load elapsed time                           0.1        .0

DB time                                          1,767.4

background elapsed time                             16.3

background cpu time                                  3.4

time:07:22:01 ~ 07:52:04

Statistic                                       Time (s) % DB time

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

sql execute elapsed time                         1,767.9      99.3

DB CPU                                           1,751.9      98.4

parse time elapsed                                  56.9       3.2

hard parse elapsed time                            53.4       3.0

hard parse (sharing criteria) elaps                  6.8        .4

connection management call elapsed                   6.6        .4

PL/SQL execution elapsed time                        5.9        .3

hard parse (bind mismatch) elapsed                   3.9        .2

PL/SQL compilation elapsed time                      0.6        .0

repeated bind elapsed time                           0.4        .0

sequence load elapsed time                           0.1        .0

DB time                                          1,780.4

background elapsed time                             12.4

background cpu time                                  1.6

 

分析:
对比4个时间段的time model system stats,发现硬解析存在,较之前平均为46.28上升为平均的49.38,近似没有太大变化,但其值已经占据大部分解析,需要进一步分析对其优化,应重点关注。

⑦Latch Sleep breakdown

time:05:52:00 ~06:22:03

                                       Get                                 Spin

Latch Name                        Requests       Misses      Sleeps        Gets

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

qmn task queue latch                   252            9           9           0

shared pool                        646,354            2           2           0

redo allocation                      1,831            1           1           0

JS Sh mem access                         5            1           1           0

FOB s.o list latch                   7,824            1           1           0

SQL memory manager latch             3,271            1           1           0

time:06:22:03 ~06:52:02

                                       Get                                 Spin

Latch Name                        Requests       Misses      Sleeps        Gets

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

shared pool                        598,719            4           4           0

qmn task queue latch                   260            3           3           0

shared pool simulator               94,784            2           2           0

row cache objects                  807,801            2           2           0

JS Sh mem access                         3            1           1           0

time:06:52:02~07:22:01

                                       Get                                 Spin

Latch Name                        Requests       Misses      Sleeps        Gets

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

shared pool                        598,719            4           4           0

qmn task queue latch                   260            3           3           0

shared pool simulator               94,784            2           2           0

row cache objects                  807,801            2           2           0

JS Sh mem access                         3            1           1           0

time:07:22:01 ~ 07:52:04

Latch Name                        Requests       Misses      Sleeps        Gets

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

qmn task queue latch                   252            9           9           0

shared pool                        646,354            2           2           0

redo allocation                      1,831            1           1           0

JS Sh mem access                         5            1           1           0

FOB s.o list latch                   7,824            1           1           0

SQL memory manager latch             3,271            1           1           0

 

分析:
观察“Latch Sleep breakdown”,比较调整之前,“qmn task queue latch”在4个时间段中出现有miss、sleep的次数稍有增加,其余项很少有misss、sleeps。

总结:

通过以上几点分析发现,将缓冲区调大后,性能有所提升,体现在如下:
① buffer hit由之前平均99.81提高为99.99%,稍有提升;
② direct path read磁盘I/O产生量虽然仍为产生I/O的最大来源,但比较于之前I/O量,由平 
   均32,438,303下降为17,596,117,I/O性能上已有显著改善;
③ Buffer Pool Advisory中发现,预估的物理读由之前平均为19000降低到10000,物理读的下
   降说明了性能的提升;
     通过分析后,性能上仍存在需改善的方面,如下:
① library hit仍低于95%,库缓冲区命中率较低;
② 以全表扫描的方式查询数据,direct path read产生较多的磁盘I/O;
③ 仍存在部分硬解析。

*****************************************************************************************

步骤四:创建索引,生成statspack报告,分析数据

目标:

1、创建索引;             

2、生成、导出报告;             

3、分析报告。

*****************************************************************************************

1、创建索引

SQL> create index ind_empno on emp2(empno);        --添加索引
$ sh script/bin/share_pool_sql_1.sh;              --执行查询业务

2、生成报告

SQL>@?/rdbms/admin/spauto                          --开启自动快照
SQL> @?/rdbms/admin/spreport                       --生成报告

3、分析报告

关注点:

①buffer hit

②library hit

③Top 5 Timed Events

④造成最大物理读的sql

⑤Buffer Pool Advisory

⑥time model system stats

⑦Latch Sleep breakdown

 

① buffer hit、②library hit

时间

Buffer  Hit(%)

Library Hit(%)

12:43:00 ~ 12:58:02

99.98

89.65

12:58:02 ~ 13:13:03

99.98

88.92

13:13:03 ~ 13:28:03

99.96

90.62

13:28:03 ~ 13:43:05

99.97

90.56

avg(now)

99.97

89.94

avg(last)

99.99

86.49

 

分析:
    buffer hit较上次变化不大,其值已满足高于90%的标准。library hit由之前平均86.49%提高为平均89.94%,稍有提升,但仍低于95%标准值,说明库缓存区命中率仍然较低,仍需做进一步调整。

③Top 5 Timed Events

时间

name

waits

Time (s)

12:43:00 ~12:58:02

Disk file operations I/O

18,849

1

log file parallel write

280

1

control file parallel write

251

1

12:58:02 ~13:13:03

Disk file operations I/O

18,641

1

log file parallel write

412

1

cursor: pin S wait on X

35

2

13:13:03 ~13:28:03

Disk file operations I/O

19,002

1

log file parallel write

190

1

control file parallel write

251

1

13:28:03 ~13:43:05

Disk file operations I/O

19,146

1

log file parallel write

224

1

control file parallel write

250

0

avg

Disk file operations I/O

18,909

 

分析:
    对于磁盘I/O的产生已由direct path read变为了Disk file operations,说明由全表扫描变成走索引了,waits值由之前平均17,630,648下降为18,909,性能上实现了显著的提高。并且log file parallel write、control file parallel write产生的部分磁盘I/O也相应下降了。由此,可以看出通过加索引显著地降低了I/O,提升了性能。

④查出造成物理读最大的前几个sql语句,产生执行计划

SQL>select sql_text from v$sql where disk_reads=(select max(disk_reads) from v$sql);  --查询造成最大物理读的sql语句
SQL_ID        SQL_TEXT         
------------- ----------------------------------------
3wmbtk9vt5pbq SELECT * FROM EMP3 WHERE EMPNO=:B1       
Plan hash value: 2607329332
-----------------------------------------------------------------------------------------
| Id  | Operation                   | Name      | Rows  | Bytes | Cost (%CPU)| Time     |
-----------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT            |           |     1 |    41 |     4   (0)| 00:00:01 |
|   1 |  TABLE ACCESS BY INDEX ROWID| EMP3      |     1 |    41 |     4   (0)| 00:00:01 |
|*  2 |   INDEX RANGE SCAN          | IND_EMPNO |     1 |       |     3   (0)| 00:00:01 |
-----------------------------------------------------------------------------------------

 

分析:
    通过对比物理读最大的sql的执行计划,发现有相同的执行计划,预判可以使用绑定变量以提高性能。

⑤Buffer Pool Advisory

statistics

Time

P

Size for

Est (M)

Size

Factr

Buffers

(thousands)

Est

Phys

Read

Factr

Estimated

Phys Reads

(thousands)

Est Phys

Read Time

 

Est

% dbtime

for Rds

 

12:43:00 ~12:58:02

D

64

1.0

8

1.0

10

7

.1

12:58:02 ~13:13:03

D

64

1.0

8

1.0

10

7

.0

13:13:03 ~13:28:03

D

64

1.0

8

1.0

10

8

.1

13:28:03 ~13:43:05

D

64

1.0

4

1.0

10

8

.1

avg(last)

 

64

1.0

6

1.0

10

7

.0

avg (now)

 

64

1.0

7

1.0

10

7.5

.0

example

Time : 12:43:00 ~12:58:02

                                   Est

                                  Phys      Estimated                   Est

    Size for  Size      Buffers   Read     Phys Reads     Est Phys % dbtime

P    Est (M) Factr  (thousands)  Factr    (thousands)    Read Time  for Rds

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

D          4    .1            0   21.6            207          196      2.5

D          8    .1            1    9.7             93           87      1.1

D         12    .2            1    4.7             45           41       .5

D         16    .3            2    3.2             31           27       .4

D         20    .3            2    2.0             19           16       .2

D         24    .4            3    1.7             16           13       .2

D         28    .4            3    1.5             14           11       .1

D         32    .5            4    1.3             12            9       .1

D         36    .6            4    1.1             11            8       .1

D         40    .6            5    1.1             11            8       .1

D         44    .7            5    1.1             10            7       .1

D         48    .8            6    1.0             10            7       .1

D         52    .8            6    1.0             10            7       .1

D         56    .9            7    1.0             10            7       .1

D         60    .9            7    1.0             10            7       .1

D        64   1.0            8    1.0             10            7       .1

D         68   1.1            8    1.0             10            7       .1

D         72   1.1            9    1.0             10            7       .1

D         76   1.2            9    1.0             10            7       .1

D         80   1.3           10    1.0             10            7       .1

分析:
     对比4个时间段中的最佳buffer pool建议,各指标数值近似与调整前持平。

⑥time model system stats

time:12:43:00 ~12:58:02

Statistic                                       Time (s) % DB time

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

DB CPU                                             393.3     159.2

parse time elapsed                                  84.6      34.3

sql execute elapsed time                            67.0      27.1

hard parse elapsed time                            65.3      26.5

connection management call elapsed                  51.8      21.0

PL/SQL execution elapsed time                        7.3       3.0

hard parse (sharing criteria) elaps                  3.8       1.6

hard parse (bind mismatch) elapsed                   2.7       1.1

PL/SQL compilation elapsed time                      1.1        .5

repeated bind elapsed time                           0.3        .1

sequence load elapsed time                           0.3        .1

DB time                                            247.0

background elapsed time                              7.7

background cpu time                                  2.2

time:12:58:02 ~13:13:03

Statistic                                       Time (s) % DB time

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

DB CPU                                             395.9     151.5

parse time elapsed                                 100.5      38.5

sql execute elapsed time                            83.8      32.1

hard parse elapsed time                            80.5      30.8

connection management call elapsed                  51.8      19.8

PL/SQL execution elapsed time                        7.6       2.9

hard parse (sharing criteria) elaps                  6.0       2.3

hard parse (bind mismatch) elapsed                   3.1       1.2

PL/SQL compilation elapsed time                      2.3        .9

sequence load elapsed time                           0.7        .3

repeated bind elapsed time                           0.5        .2

DB time                                            261.2

background elapsed time                              9.8

background cpu time                                  4.3

time:13:13:03 ~13:28:03

Statistic                                       Time (s) % DB time

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

DB CPU                                             378.0     171.7

parse time elapsed                                  62.6      28.4

connection management call elapsed                  47.4      21.6

sql execute elapsed time                            44.8      20.4

hard parse elapsed time                            43.3      19.6

PL/SQL execution elapsed time                        6.7       3.0

hard parse (sharing criteria) elaps                  2.5       1.1

hard parse (bind mismatch) elapsed                   1.8        .8

PL/SQL compilation elapsed time                      0.4        .2

repeated bind elapsed time                           0.1        .0

sequence load elapsed time                           0.1        .0

DB time                                            220.1

background elapsed time                              5.2

background cpu time                                  0.8

time:13:28:03 ~13:43:05

Statistic                                       Time (s) % DB time

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

DB CPU                                             375.8     170.5

parse time elapsed                                  62.4      28.3

connection management call elapsed                  47.5      21.5

sql execute elapsed time                            45.7      20.7

hard parse elapsed time                            43.2      19.6

PL/SQL execution elapsed time                        6.9       3.1

hard parse (sharing criteria) elaps                  2.3       1.1

hard parse (bind mismatch) elapsed                   1.7        .8

PL/SQL compilation elapsed time                      0.4        .2

repeated bind elapsed time                           0.1        .1

sequence load elapsed time                           0.0        .0

DB time                                            220.5

background elapsed time                              5.7

background cpu time                                  1.1

分析:
    对比4个时间段的time model system stats,发现仍有硬解析存在,较之前平均为49.38上升为平均的58.08,说明硬解析有所增加,对性能已经造影响,需要调整。

⑦Latch Sleep breakdown

time:12:43:00 ~12:58:02

                                       Get                                 Spin

Latch Name                        Requests       Misses      Sleeps        Gets

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

cache buffers chains             1,773,511           20           1          19

shared pool                      2,017,327           10          10           0

space background task latc             567            2           2           0

row cache objects                2,796,969            2           2           0

call allocation                     66,319            1           1           0

time:12:58:02 ~13:13:03

                                       Get                                 Spin

Latch Name                        Requests       Misses      Sleeps        Gets

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

cache buffers chains             2,114,166           70           2          68

shared pool                      2,190,149            9           9           0

row cache objects                3,062,858            8           7           1

space background task latc             564            2           2           0

JS Sh mem access                         4            1           1           0

enqueue hash chains                153,468            1           1           0

time:13:13:03 ~013:28:03

                                       Get                                 Spin

Latch Name                        Requests       Misses      Sleeps        Gets

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

shared pool                      1,807,752            5           5           0

space background task latc             565            3           3           0

row cache objects                2,526,040            1           1           0

shared pool simulator              319,487            1           1           0

JS Sh mem access                         3            1           1           0

time:13:28:03 ~13:43:05

Latch Name                        Requests       Misses      Sleeps        Gets

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

shared pool                      1,838,349            8           8           0

space background task latc             574            4           4           0

JS Sh mem access                         3            1           1           0

SQL memory manager workare          86,098            1           1           0

分析:
      观察“Latch Sleep breakdown”,在平均的时间段内,发生misss、sleeps的次数并不显著。

总结:

   通过以上几点分析发现,将缓冲区调大后,性能有所提升,通过Disk file operations发现,磁盘I/O 
性能显著提升;
    通过分析后,性能上仍存在需改善的地方:存在硬解析、库缓冲命中率较低。

*****************************************************************************************

步骤五:使用绑定变量,生成 statspack报告,分析数据

目标:

1、使用绑定变量;             

2、生成、导出报告;             

3、分析报告。

*****************************************************************************************

1、使用绑定变量

$ vi script/bin/share_pool_sql_2.sh --重新编写查询的业务脚本,语句中加入绑定变量
sqlplus scott/tiger <<EOF
declare
  v_empno emp2.empno%type;
  v_emp2  emp2%rowtype;
begin
        v_empno := 1;
        while v_empno<=2000000 loop
                v_empno :=v_empno + 1;
          select * into v_emp2
          from emp2 where empno=v_empno;
	if v_empno=2000000 then
	  v_empno:=1;
	end if;
        end loop;
end;
/

2、生成报告

$ sh script/bin/share_pool_sql_2.sh      --执行加入绑定变量的业务脚本
SQL> @?/rdbms/admin/spreport        --通过快照,生成报告

3、分析报告

关注点:

①buffer hit

②library hit

③Top 5 Timed Events

④造成最大物理读的sql

⑤Buffer Pool Advisory

⑥time model system stats

⑦Latch Sleep breakdown

 

① buffer hit、②library hit

时间

Buffer  Hit(%)

Library Hit(%)

16:34:03 ~ 16:49:02

99.76

99.99

16:49:02 ~ 17:04:01

99.76

99.98

17:04:01 ~ 17:19:00

99.76

99.99

17:19:00 ~ 17:34:00

99.76

99.99

avg(last)

99.97

89.94

avg

99.76

99.99

分析:
    buffer hit较上次变化不大,其值已满足高于90%的标准;
library hit由之前平均89.94%提高为平均99.99%(高出95%的标准),库缓存区命中率已达到显著提 
升;
    buffer hit、library hit都达到高性能值。

③Top 5 Timed Events

时间

name

waits

Time (s)

16:34:03 ~16:49:02

db file sequential read

289,756

22

cursor: pin S

110

11

cursor: mutex S

19

2

16:49:02 ~17:04:01

db file sequential read

294,214

19

cursor: pin S

105

11

cursor: mutex S

24

2

17:04:01 ~17:19:00

db file sequential read

294,404

13

cursor: pin S

90

9

cursor: mutex S

31

3

17:19:00 ~17:34:00

db file sequential read

296,040

9

cursor: pin S

104

11

cursor: mutex S

32

3

avg

db file sequential read

293,603

 

分析:
    对于磁盘I/O的产生,由之前产生最大I/O的“Disk file operations I/O”的waits: 18,909变成了“db file sequential read”产生的waits :293,603,I/O有所提升,性能上是可以接受的。 

④查出造成物理读最大的前几个sql语句,产生执行计划

SQL>select sql_text from v$sql where disk_reads=(select max(disk_reads) from v$sql);  --查询造成最大物理读的sql语句
SQL_ID        SQL_TEXT         
------------- ----------------------------------------
3wmbtk9vt5pbq SELECT * FROM EMP3 WHERE EMPNO=:B1       
Plan hash value: 2607329332
-----------------------------------------------------------------------------------------
| Id  | Operation                   | Name      | Rows  | Bytes | Cost (%CPU)| Time     |
-----------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT            |           |     1 |    41 |     4   (0)| 00:00:01 |
|   1 |  TABLE ACCESS BY INDEX ROWID| EMP3      |     1 |    41 |     4   (0)| 00:00:01 |
|*  2 |   INDEX RANGE SCAN          | IND_EMPNO |     1 |       |     3   (0)| 00:00:01 |
-----------------------------------------------------------------------------------------

 

分析:
    通过对比物理读最大的sql的执行计划,发现重用的执行计划已经使用绑定变量,所以性能已经达到最佳。

⑤Buffer Pool Advisory

statistics

Time

P

Size for

Est (M)

Size

Factr

Buffers

(thousands)

Est

Phys

Read

Factr

Estimated

Phys Reads

(thousands)

Est Phys

Read Time

 

Est

% dbtime

for Rds

 

16:34:03 ~16:49:02

D

64

1.0

8

1.0

712

490

3.8

16:49:02 ~17:04:01

D

64

1.0

8

1.0

1,007

509

3.4

17:04:01 ~17:19:00

D

64

1.0

8

1.0

1,301

522

3.1

17:19:00 ~17:34:00

D

64

1.0

8

1.0

1,597

531

2.9

avg(now)

 

64

1.0

8

1.0

1,132

513

3.3

avg (last)

 

64

1.0

7

1.0

10

7.5

.0

example

Time : 16:34:03 ~16:49:02

                                   Est

                                  Phys      Estimated                   Est

    Size for  Size      Buffers   Read     Phys Reads     Est Phys % dbtime

P    Est (M) Factr  (thousands)  Factr    (thousands)    Read Time  for Rds

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

D          4    .1            0    1.7          1,177          811      6.3

D          8    .1            1    1.3            934          643      5.0

D         12    .2            1    1.2            824          567      4.4

D         16    .3            2    1.1            778          535      4.1

D         20    .3            2    1.1            750          516      4.0

D         24    .4            3    1.0            741          510      3.9

D         28    .4            3    1.0            731          503      3.9

D         32    .5            4    1.0            724          498      3.8

D         36    .6            4    1.0            721          496      3.8

D         40    .6            5    1.0            719          495      3.8

D         44    .7            5    1.0            718          494      3.8

D         48    .8            6    1.0            716          493      3.8

D         52    .8            6    1.0            713          491      3.8

D         56    .9            7    1.0            713          491      3.8

D         60    .9            7    1.0            713          490      3.8

D         64   1.0            8    1.0            712          490      3.8

D         68   1.1            8    1.0            712          490      3.8

D         72   1.1            9    1.0            711          489      3.8

D         76   1.2            9    1.0            711          489      3.8

D         80   1.3           10    1.0            711          489      3.8

分析:
通过4个时间段进行对比,发现buffer pool的尺寸对性能的影响已经稳定了,无需再调整缓冲区的大小了。

⑥time model system stats

time:16:34:03 ~16:49:02

Statistic                                       Time (s) % DB time

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

sql execute elapsed time                         1,810.3     100.2

DB CPU                                             896.4      49.6

PL/SQL execution elapsed time                      219.0      12.1

parse time elapsed                                  10.8        .6

hard parse elapsed time                            10.5        .6

hard parse (sharing criteria) elaps                  0.9        .1

hard parse (bind mismatch) elapsed                   0.2        .0

PL/SQL compilation elapsed time                      0.1        .0

repeated bind elapsed time                           0.1        .0

sequence load elapsed time                           0.0        .0

DB time                                          1,807.6

background elapsed time                              8.1

background cpu time                                  0.7

time:16:49:02 ~17:04:01

Statistic                                       Time (s) % DB time

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

sql execute elapsed time                         1,812.9     100.1

DB CPU                                             896.6      49.5

PL/SQL execution elapsed time                      217.1      12.0

parse time elapsed                                   9.7        .5

hard parse elapsed time                             8.7        .5

hard parse (sharing criteria) elaps                  0.8        .0

hard parse (bind mismatch) elapsed                   0.1        .0

PL/SQL compilation elapsed time                      0.1        .0

repeated bind elapsed time                           0.1        .0

sequence load elapsed time                           0.0        .0

DB time                                          1,810.8

background elapsed time                             13.9

background cpu time                                  2.4

time:17:04:01 ~17:19:00

Statistic                                       Time (s) % DB time

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

sql execute elapsed time                         1,811.9     100.2

DB CPU                                             898.3      49.7

PL/SQL execution elapsed time                      218.1      12.1

parse time elapsed                                   6.8        .4

hard parse elapsed time                             6.2        .3

hard parse (sharing criteria) elaps                  0.5        .0

hard parse (bind mismatch) elapsed                   0.3        .0

repeated bind elapsed time                           0.1        .0

PL/SQL compilation elapsed time                      0.1        .0

sequence load elapsed time                           0.0        .0

DB time                                          1,808.3

background elapsed time                              7.1

background cpu time                                  0.6

time:17:19:00 ~17:34:00

Statistic                                       Time (s) % DB time

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

sql execute elapsed time                         1,811.3     100.2

DB CPU                                             899.4      49.7

PL/SQL execution elapsed time                      222.6      12.3

parse time elapsed                                   8.1        .4

hard parse elapsed time                             7.9        .4

hard parse (sharing criteria) elaps                  1.6        .1

hard parse (bind mismatch) elapsed                   0.1        .0

PL/SQL compilation elapsed time                      0.1        .0

repeated bind elapsed time                           0.0        .0

sequence load elapsed time                           0.0        .0

DB time                                          1,808.5

background elapsed time                              6.1

background cpu time                                  0.6

分析:
对比4个时间段的hard parse elapsed time,发现硬解析已经由原来平均的58.08下降到平均8.3,说明绑定变量后的重用执行计划,大大的降低了硬解析的次数。所以,对于硬解析的性能问题已经得到了解决。

⑦Latch Sleep breakdown

time:16:34:03 ~16:49:02

                                       Get                                 Spin

Latch Name                        Requests       Misses      Sleeps        Gets

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

cache buffers chains           178,903,796      564,805          20     564,785

cache buffers lru chain            290,646            4           4           0

redo allocation                      1,095            4           4           0

simulator lru latch                    384            1           1           0

JS Sh mem access                         3            1           1           0

time:16:49:02 ~17:04:01

                                       Get                                 Spin

Latch Name                        Requests       Misses      Sleeps        Gets

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

cache buffers chains           181,404,031      512,003          23     511,980

cache buffers lru chain            295,633            8           8           0

shared pool                     10,639,749            4           4           0

time:17:04:01 ~17:19:00

                                       Get                                 Spin

Latch Name                        Requests       Misses      Sleeps        Gets

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

cache buffers chains           181,912,648      596,092          28     596,064

cache buffers lru chain            295,426            7           7           0

shared pool                     10,382,962            2           2           0

simulator lru latch                    388            1           1           0

JS Sh mem access                         3            1           1           0

time:17:19:00 ~17:34:00

                                       Get                                 Spin

Latch Name                        Requests       Misses      Sleeps        Gets

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

cache buffers chains           182,649,027      589,449          23     589,426

cache buffers lru chain            296,763            5           5           0

simulator hash latch             5,532,691            1           1           0

qmn task queue latch                   128            1           1           0

shared pool                     10,743,634            1           1           0

JS Sh mem access                         3            1           1           0

分析:
观察“Latch Sleep breakdown”,在平均的时间段内,cache buffers chains发生misss、sleeps的次数较多,而"cache buffers lru chain",发生misss、sleeps的次数比较少。

总结:

通过以上几点分析,解决了库缓冲区命中率低、硬解析数量大的情况。数据库的性能已经得到了较好的提升。

***********************************************声明*********************************************************************** 

原创作品,出自 “深蓝的blog” 博客,欢迎转载,转载时请务必注明出处,否则追究版权法律责任。

深蓝的blog:http://blog.csdn.net/huangyanlong/article/details/39803995

***************************************************************************************************************************

系列链接:

蓝的成长记——追逐DBA(1):奔波于路上,挺进山东 

蓝的成长记——追逐DBA(2):安装!安装!久违的记忆,引起我对DBA的重新认知

蓝的成长记——追逐DBA(3):古董上操作,数据导入导出成了问题 

蓝的成长记——追逐DBA(4):追忆少年情愁,再探oracle安装(Linux下10g、11g) 

蓝的成长记——追逐DBA(5):不谈技术谈业务,恼人的应用系统

蓝的成长记——追逐DBA(6): 做事与做人:小技术,大为人

蓝的成长记——追逐DBA(7):基础命令,地基之石 

 

蓝的成长记——追逐DBA(8):重拾SP报告,回忆oracle的STATSPACK实验

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