性能比较工具runstats

    runstats能对做同一件事的两个不同方法进行比较，得出谁好一点。我们只需要提供两个不同方法，余下的事情都由runstats负责。runstats只是测量3个要素：

    1. 耗用的时间。

    2. 系统统计结果：会并排地显示每个方法做某件事(如执行一个解析调用)的次数，并展示二者之差。

    3. latching,这是报告关键的输出。

    安装过程：

   

create global temporary table run_stats

(  runid varchar2(15),

   name varchar2(80),

   value int )

on commit preserve rows;



create or replace view stats as select 'STAT...' || a.name name, b.value

   from v$statname a, v$mystat b

where a.statistic# = b.statistic#

union all

  select 'LATCH.' || name, gets from v$latch

union all

  select 'STAT...Elapsed Time', hsecs from v$timer;

  

  

create or replace package runstats_pkg

as

procedure rs_start;

procedure rs_middle;

procedure rs_stop( p_difference_threshold in number default 0 );

end;

/



create or replace package body runstats_pkg

as

  g_start number;

  g_run1 number;

  g_run2 number;

procedure rs_start

is

begin

  delete from run_stats;

  insert into run_stats select 'before', stats.* from stats;

  g_start := dbms_utility.get_time;

end;

procedure rs_middle

is

begin

  g_run1 := (dbms_utility.get_time-g_start);

  insert into run_stats  select 'after 1', stats.* from stats;

  g_start := dbms_utility.get_time;

end;

procedure rs_stop(p_difference_threshold in number default 0)

is

begin

 g_run2 := (dbms_utility.get_time-g_start);

 dbms_output.put_line

 ( 'Run1 ran in ' || g_run1 || ' hsecs' );

 dbms_output.put_line

 ( 'Run2 ran in ' || g_run2 || ' hsecs' );

if ( g_run2 <> 0 ) then

 dbms_output.put_line

 ( 'run 1 ran in ' || round(g_run1/g_run2*100,2) ||'% of the time' );

end if;

dbms_output.put_line( chr(9) );

insert into run_stats select 'after 2', stats.* from stats;

dbms_output.put_line

( rpad( 'Name', 30 ) || lpad( 'Run1', 12 ) ||lpad( 'Run2', 12 ) || lpad( 'Diff', 12 ) );

for x in

( select rpad( a.name, 30 ) ||

to_char( b.value-a.value, '999,999,999' ) ||to_char( c.value-b.value, '999,999,999' ) ||

to_char( ( (c.value-b.value)-(b.value-a.value)), '999,999,999' ) data

from run_stats a, run_stats b, run_stats c

where a.name = b.name

and b.name = c.name

and a.runid = 'before'

and b.runid = 'after 1'

and c.runid = 'after 2'

and abs( (c.value-b.value) - (b.value-a.value) )> p_difference_threshold

order by abs( (c.value-b.value)-(b.value-a.value))

) loop

dbms_output.put_line( x.data );

end loop;

dbms_output.put_line( chr(9) );

dbms_output.put_line

( 'Run1 latches total versus runs -- difference and pct' );

dbms_output.put_line

( lpad( 'Run1', 12 ) || lpad( 'Run2', 12 ) ||

lpad( 'Diff', 12 ) || lpad( 'Pct', 10 ) );

for x in

( select to_char( run1, '999,999,999' ) ||

to_char( run2, '999,999,999' ) ||

to_char( diff, '999,999,999' ) ||

to_char( round( run1/decode( run2, 0, to_number(0), run2) *100,2 ), '99,999.99' ) || '%' data

from ( select sum(b.value-a.value) run1, sum(c.value-b.value) run2, sum( (c.value-b.value)-(b.value-a.value)) diff

from run_stats a, run_stats b, run_stats c

where a.name = b.name

and b.name = c.name

and a.runid = 'before'

and b.runid = 'after 1'

and c.runid = 'after 2'

and a.name like 'LATCH%'

)

) loop

dbms_output.put_line( x.data );

end loop;

end;

end;

/ 

试验设计，测试对比加不加绑定变量的情况： 

 

--测试过程的sql

drop table t purge;

create table t ( x int );

--无绑定变量

create or replace procedure p1

as l_cnt number;

begin

for i in 1 .. 10000

  loop

    execute immediate 'select count(*) from t where x = ' || i into l_cnt;

  end loop;

end;

/

--绑定变量 

create or replace procedure p2

as l_cnt number;

begin

for i in 1 .. 10000

  loop

    select count(*) into l_cnt from t where x = i;

  end loop;

end;

/ 



exec runStats_pkg.rs_start;

exec p1;

exec runStats_pkg.rs_middle;

set serveroutput on;

exec p2;

exec runStats_pkg.rs_stop(1000);

 

 

测试结果：

Run1 ran in 311 hsecs
Run2 ran in 30 hsecs
run 1 ran in 1036.67% of the time

Name                                  Run1        Run2        Diff
STAT...bytes sent via SQL*Net          276       1,524       1,248
LATCH.session allocation             1,695          74      -1,621
STAT...parse count (hard)           10,011           5     -10,006
STAT...enqueue releases             10,016           8     -10,008
STAT...enqueue requests             10,017           8     -10,009
STAT...parse count (total)          10,041          14     -10,027
STAT...calls to get snapshot s      50,073      40,020     -10,053
STAT...consistent gets              40,194      30,060     -10,134
STAT...consistent gets from ca      40,194      30,060     -10,134
STAT...session logical reads        40,232      30,087     -10,145
STAT...recursive calls              20,920      10,076     -10,844
LATCH.enqueue hash chains           20,117          16     -20,101
LATCH.enqueues                      20,124          18     -20,106
LATCH.cache buffers chains          80,492      60,209     -20,283
STAT...physical read total byt           0      24,576      24,576
STAT...physical read bytes               0      24,576      24,576
LATCH.kks stats                     25,415          10     -25,405
LATCH.library cache pin             70,385      20,185     -50,200
STAT...session uga memory           65,560       7,488     -58,072
LATCH.library cache lock            60,292         179     -60,113
STAT...session pga memory           65,536           0     -65,536
LATCH.row cache objects            150,201         356    -149,845
LATCH.shared pool                  206,050      10,230    -195,820
STAT...session uga memory max      261,964      65,560    -196,404
LATCH.library cache                216,965      20,474    -196,491
STAT...session pga memory max      262,144      65,536    -196,608

Run1 latches total versus runs -- difference and pct
Run1        Run2        Diff       Pct
854,415     111,834    -742,581    764.00%