假设你不小心覆盖了之前的存储过程，那得赶紧闪回，时长越长闪回的可能性越小。原理非常easy，存储过程的定义就是数据字典，改动数据字典跟改动普通表的数据没有差别，此时会把改动前的内容放到undo中，我们能够依据这一点来进行闪回，所以我说要尽快，要不然找不回来了。以下我们来做一个实验：
1.在用户TEST下14:31下建立存储过程
create or replace procedure GG_TEST
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;
2.在用户TEST下在14:33下删除存储过程
drop procedure GG_TEST;
3.登录到sys账户下
create table p_temp as
select *
from dba_source as of timestamp TO_TIMESTAMP('2014-05-04 14:33:00', 'YYYY-MM-DD HH24:MI:SS')
where TYPE = 'PROCEDURE'
And owner = 'TEST'
And Name = 'GG_TEST';
select text
from p_temp
where name like upper('%GG_TEST%')
and owner = 'TEST'
order by line;
TEXT
---------------------------------------------------------------------------
procedure GG_TEST
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;