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 bwhere a.statistic# = b.statistic#union all  select 'LATCH.' || name, gets from v$latchunion all  select 'STAT...Elapsed Time', hsecs from v$timer;    create or replace package runstats_pkgasprocedure rs_start;procedure rs_middle;procedure rs_stop( p_difference_threshold in number default 0 );end;/create or replace package body runstats_pkgas  g_start number;  g_run1 number;  g_run2 number;procedure rs_startisbegin  delete from run_stats;  insert into run_stats select 'before', stats.* from stats;  g_start := dbms_utility.get_time;end;procedure rs_middleisbegin  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)isbegin 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' ) datafrom run_stats a, run_stats b, run_stats cwhere a.name = b.nameand b.name = c.nameand 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_thresholdorder by abs( (c.value-b.value)-(b.value-a.value))) loopdbms_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' ) || '%' datafrom ( select sum(b.value-a.value) run1, sum(c.value-b.value) run2, sum( (c.value-b.value)-(b.value-a.value)) difffrom run_stats a, run_stats b, run_stats cwhere a.name = b.nameand b.name = c.nameand a.runid = 'before'and b.runid = 'after 1'and c.runid = 'after 2'and a.name like 'LATCH%')) loopdbms_output.put_line( x.data );end loop;end;end;/ 

--测试过程的sql

drop table t purge;create table t ( x int );--无绑定变量create or replace procedure p1as l_cnt number;beginfor 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 p2as l_cnt number;beginfor 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%