验证日志增长

---- 1 window
conn scott/tiger;
select * from tab;
drop table t1;
create table t1 as emp;
insert  into  t1 select * from t1;
/
/
/
/
/
commit;


-- 2.window
sqlplus / as sysdba;
conn / as sysdba;
SELECT * from v$sysstat where class=2;
select value from v$sysstat where STATISTIC#=178;  -- 178 是上条语句查出的 redo size 对应的 statistic# 号
SQL> SELECT value from v$sysstat where STATISTIC#=178;

     VALUE
----------
   3776244
   

-- 1.window
update t1 set sal=sal+1 where empno=7900;
commit;

-- 2.window
SELECT value from v$sysstat where STATISTIC#=178;  -- 注意比刚才大了； 约几M ，这里假定 3M
alter tablespace users begin backup;  -- 冻结表空间；

-- 1.window
update t1 set sal=sal+1 where empno=7900;
commit;

-- 2.window
SELECT value from v$sysstat where STATISTIC#=178;  -- 注意第一次update大好； 增长一倍
alter tablespace users end backup;