对比append插入数据产生的redo量

--版本信息
SELECT * FROM v$version;
Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - Prod
PL/SQL Release 10.2.0.5.0 - Production
CORE    10.2.0.5.0    Production
TNS for 32-bit Windows: Version 10.2.0.5.0 - Production
NLSRTL Version 10.2.0.5.0 - Production

--查看是否归档
select name,log_mode from v$database;
1    ORCL NOARCHIVELOG
或sqlplus:ARCHIVE LOG LIST;

--创建查看产生redo大小的视图
create or replace view redo_size as
select value
from v$mystat, v$statname
where v$mystat.statistic# = v$statname.statistic#
and v$statname.name = ‘redo size‘;

--!!!!!!!!!!!非归档模式 产生的redo!!!!!!!!!!!!!!!!!!
--==============nologging表================
SELECT * FROM sys.redo_size;
--redo_size:0
create table test_nolog nologging as select * from dba_objects where 1=0;
--redo_size:17932
insert into test_nolog select * from dba_objects;
--redo_size:5772780 
insert /*+ APPEND */  into test_nolog select * from dba_objects;
--redo_size:5782548
select (5782548-5772780) redo_append, (5772780-17932) redo_normal from dual;
9768    5754848
--================logging============================
--redo_size:11778596
create table test_log as select * from dba_objects where 1=0;
--redo_size:11799284
insert into test_log select * from dba_objects;
--redo_size:17555812
insert /*+ APPEND */  into test_log select * from dba_objects;
--redo_size:17565544
select (17565544-17555812) redo_append, (17555812-11799284) redo_normal from dual;
9732    5756528

--修改为归档模式
set ORACLE_SID=ORCL
sqlplus / as sysdba

SYS@ORCL> archive log list
数据库日志模式             非存档模式
自动存档             禁用
存档终点            USE_DB_RECOVERY_FILE_DEST
最早的联机日志序列     544
当前日志序列           546
SYS@ORCL> select log_mode from v$database;
LOG_MODE
------------
NOARCHIVELOG

SYS@ORCL> shutdown immediate
数据库已经关闭。
已经卸载数据库。
ORACLE 例程已经关闭。
SYS@ORCL> startup mount
ORACLE 例程已经启动。

Total System Global Area 1258291200 bytes
Fixed Size                  1304848 bytes
Variable Size             201328368 bytes
Database Buffers         1048576000 bytes
Redo Buffers                7081984 bytes
数据库装载完毕。
SYS@ORCL> alter database ARCHIVELOG;

数据库已更改。
SYS@ORCL> archive log list
数据库日志模式            存档模式
自动存档             启用
存档终点            USE_DB_RECOVERY_FILE_DEST
最早的联机日志序列     544
下一个存档日志序列   546
当前日志序列           546
SYS@ORCL> alter database open;

数据库已更改。

--!!!!!!!!!!!归档模式 产生的redo!!!!!!!!!!!!!!!!!!
--==============nologging表================
SELECT * FROM redo_size;
--redo_size:0
insert into test_nolog select * from dba_objects;
--redo_size:5729772 
insert /*+ APPEND */  into test_nolog select * from dba_objects;
--redo_size:5739436
select (5739436-5729772) redo_append, (5729772-0) redo_normal from dual;
9664  5729772
--================loging============================
--redo_size:5729772
insert into test_log select * from dba_objects;
--redo_size:11355620
insert /*+ APPEND */  into test_log select * from dba_objects;
--redo_size:17123736
select (17123736-11355620) redo_append, (11355620-5729772) redo_normal from dual;
5768116  5625848