runstats是tom写的一个用来比较同一事件的不同方法的工具。
今天测试一个语句用group by和不用效率有何不同时，头儿建议用runstats来看。
第一次用，很好很强大。
1、以sys用户登录，执行下列分配权限语句。要执行runstats的用户叫zhaoss
grant select on sys.v_$timer to zhaoss;
grant select on v_$mystat to zhaoss;
grant select on sys.v_$statname to zhaoss;
grant select on sys.v_$latch to zhaoss;
2、以zhaoss用户登录，执行下列语句创建runstats包：
a>创建stats视图：
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;
b>创建run_stats全局临时表：
create global temporary table run_stats ( runid varchar2( 15),
name varchar2(80 ),
value int
)
on commit preserve rows;
c>创建runstats包定义：
rs_start：执行第一种方法前使用，用来记录执行前状态；
rs_middle：执行完第一种方法后，执行第二种方法前执行，用来记录执行完第一种方法后状态；
rs_stop：执行完第二种方法后使用，用来生成最终结果。
create or replace package runstats as
procedure rs_start;
procedure rs_middle;
procedure rs_stop(p_difference_threshold in number default 0);
end;
d>创建runstats包体：
create or replace package body runstats 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);
--add a line here to avoid ora-20000
dbms_output.enable( 480000);
dbms_output.put_line( 'Run1 ran in ' || g_run1 || ' hsecs' );
dbms_output.put_line( 'Run2 ran in ' || g_run2 || ' hsecs' );
dbms_output.put_line( 'run 1 ran in ' ||
round(g_run1 / g_run2 * 100 , 2) ||
'% of the time');
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)),
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 (c.value-a.value) > 0
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 / 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;
使用说明：
可以使用
set serveroutput on
或者
spool 1.txt
set serveroutput on
spool off
来显示或在文件保存输出结果。
SQL> exec runstats.rs_start;
SQL> 第一个执行语句;
SQL> exec runstats.rs_middle;
SQL> 第二个执行语句;
SQL> exec runstats.rs_stop;
