dd操作数据文件

1.dd主要参数

       Copy a file, converting and formatting according to the operands.

       bs=BYTES
              force ibs=BYTES and obs=BYTES

       cbs=BYTES
              convert BYTES bytes at a time

       count=BLOCKS
              copy only BLOCKS input blocks

       ibs=BYTES
              read BYTES bytes at a time

       if=FILE
              read from FILE instead of stdin

       obs=BYTES
              write BYTES bytes at a time

       of=FILE
              write to FILE instead of stdout

       seek=BLOCKS
              skip BLOCKS obs-sized blocks at start of output

       skip=BLOCKS
              skip BLOCKS ibs-sized blocks at start of input

2.拷贝数据文件头部

[oracle@node1 chf]$ dd if=system01.dbf of=/tmp/dd_xifenfei01.dbf bs=8192 count=1
1+0 records in
1+0 records out
8192 bytes (8.2 kB) copied, 6.2e-05 seconds, 132 MB/s
[oracle@node1 chf]$ ll /tmp/dd_xifenfei01.dbf
-rw-r--r-- 1 oracle oinstall 8192 01-13 16:49 /tmp/dd_xifenfei01.dbf


BBED> set filename '/tmp/dd_xifenfei01.dbf'
        FILENAME        /tmp/dd_xifenfei01.dbf

BBED> set block 1
        BLOCK#          1

BBED> dump
 File: ././dd_xifenfei01.dbf (0)
 Block: 1                Offsets:    0 to  511           Dba:0x00000000
------------------------------------------------------------------------
 00a20000 0000c0ff 00000000 00000000 64590000 00200000 00a30200 7d7c7b7a 
 a0810000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 

 <32 bytes per line>

BBED> set block 2
BBED-00309: out of range block number (2)


BBED> set offset 8190
        OFFSET          8190

BBED> dump
 File: ././dd_xifenfei01.dbf (0)
 Block: 1                Offsets: 8190 to 8191           Dba:0x00000000
------------------------------------------------------------------------
 0000 

 <32 bytes per line>
--证明只有1个数据块(8192),并且拷贝数据文件头部成功

3.模拟创建文件

[oracle@node1 tmp]$ ll /tmp/dd_xifenfei02.dbf -h
-rw-r--r-- 1 oracle oinstall 1.0G 01-13 16:58 /tmp/dd_xifenfei02.dbf

4.拷贝数据块到一个文件中

[oracle@node1 chf]$ dd if=/tmp/dd_xifenfei01.dbf of=/tmp/dd_xifenfei02.dbf bs=8192 count=1
1+0 records in
1+0 records out
8192 bytes (8.2 kB) copied, 6e-05 seconds, 137 MB/s
[oracle@node1 chf]$ bbed
Password: 

BBED: Release 2.0.0.0.0 - Limited Production on Fri Jan 13 17:01:02 2012

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

************* !!! For Oracle Internal Use only !!! ***************

BBED> set filename '/tmp/dd_xifenfei02.dbf'

BBED> set block 1
        BLOCK#          1

BBED> dump
 File: ././dd_xifenfei02.dbf (0)
 Block: 1                Offsets:    0 to  511           Dba:0x00000000
------------------------------------------------------------------------
 00a20000 0000c0ff 00000000 00000000 64590000 00200000 00a30200 7d7c7b7a 
 a0810000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 

 <32 bytes per line>


BBED> set block 2
BBED-00309: out of range block number (2)


BBED> set offset 8190
        OFFSET          8190

BBED> dump
 File: ././dd_xifenfei02.dbf (0)
 Block: 1                Offsets: 8190 to 8191           Dba:0x00000000
------------------------------------------------------------------------
 0000 

 <32 bytes per line>

通过对比在2步骤中拷贝出来的数据文件头部,证明现在已经把该头部拷贝到了3步骤创建的新文件中

诡异dblink问题解决–dblink insert操作数据类型发生改变

1.展示列属性

[oracle@saas-xunzhi-db1 ~]$ sqlplus testga/testga

SQL*Plus: Release 10.2.0.1.0 - Production on Thu Jan 12 16:26:56 2012

Copyright (c) 1982, 2005, Oracle.  All rights reserved.


Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options

SQL> desc t_xifenfei;
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 PROCESS_INSTANCE_ID                       NOT NULL NUMBER(10)
 STATUS_NEW                                         NUMBER
 PACKAGE_NAME                                       VARCHAR2(50)

SQL> desc wf_proc_inst@oldmoa
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 ID                                        NOT NULL NUMBER(10)
 NAME                                               VARCHAR2(500)
 PROC_ID                                   NOT NULL NUMBER(10)
 PARE_INST_ID                              NOT NULL NUMBER(10)
 PARE_ACTI_ID                              NOT NULL NUMBER(10)
 INST_CREATOR                                       VARCHAR2(40)
 CREAT_DATE                                         DATE
 STATUS                                             CHAR(1)
 ATT1                                               NUMBER(10)
 ATT2                                               VARCHAR2(255)
 SEQVALUE                                           VARCHAR2(50)

从这里可以看出,原表的status列是char,而目标表的STATUS_NEW列是number类型

2.通过dblink查询列值

SQL> select t.inst_id as ID,
  2         case w.status
  3           when '0' then
  4            4
  5           when '2' then
  6            3
  7           else
  8            1
  9         end as  status_new,
 10         p.name as PACKAGE_NAME
 11    from wf_proc_inst@oldmoa i
 12    left join wf_proc_info_inst@oldmoa t on t.inst_id = i.id
 13    left join wf_proc_type@oldmoa p on t.type_id = p.id
 14    left join wf_proc_inst@oldmoa w on t.inst_id = w.id
 15   where t.inst_id = i.id
 16     and t.proc_id <> 53
 17     and t.is_ok = 1
 18     AND t.inst_id <= 4837 
 19     AND t.inst_id>=4735;

        ID STATUS_NEW PACKAGE_NAME
---------- ---------- --------------------------
      4755          3 呈批处理
      4836          3 公文处理

从这里可以看出来,case工作正常,传入的char类型,通过case转换为number类型

3.使用dblink插入数据并查询

SQL> INSERT INTO t_xifenfei
  2  select t.inst_id as ID,
  3         case w.status
  4           when '0' then
  5            4
  6           when '2' then
  7            3
  8           else
  9            1
 10         end as  status_new,
 11         p.name as PACKAGE_NAME
 12    from wf_proc_inst@oldmoa i
 13    left join wf_proc_info_inst@oldmoa t on t.inst_id = i.id
 14    left join wf_proc_type@oldmoa p on t.type_id = p.id
 15    left join wf_proc_inst@oldmoa w on t.inst_id = w.id
 16   where t.inst_id = i.id
 17     and t.proc_id <> 53
 18     and t.is_ok = 1
 19     AND t.inst_id <= 4837 
 20     AND t.inst_id>=4735;

2 rows created.

SQL> commit;

Commit complete.

SQL> col package_name for a10
SQL> select * from t_xifenfei;

PROCESS_INSTANCE_ID STATUS_NEW PACKAGE_NA
------------------- ---------- ----------
               4755          1 呈批处理
               4836          1 公文处理

这里出现异常,怀疑case中传入的值,都走到else那边了,怀疑是在使用dblink 的时候,char的类型发生的改变,转为了number,导致case匹配失败,所以走到else。

4.在dblink端创建视图,插入数据

SQL> CREATE VIEW GZZJ.v_xifenfei
  2  AS
  3  select t.inst_id as ID,
  4         case to_char(w.status)
  5           when '0' then
  6            4
  7           when '2' then
  8            3
  9           else
 10            1
 11         end as  status_new,
 12         p.name as PACKAGE_NAME
 13    from GZZJ.wf_proc_inst i
 14    left join GZZJ.wf_proc_info_inst t on t.inst_id = i.id
 15    left join GZZJ.wf_proc_type p on t.type_id = p.id
 16    left join GZZJ.wf_proc_inst w on t.inst_id = w.id
 17   where t.inst_id = i.id
 18     and t.proc_id <> 53
 19     and t.is_ok = 1
 20     AND t.inst_id <= 4837 
 21     AND t.inst_id>=4735;

View created.

SQL> insert into t_xifenfei 
  2  select * from v_xifenfei@oldmoa;

2 rows created.

SQL> commit;

Commit complete.

SQL> select * from t_xifenfei;

PROCESS_INSTANCE_ID STATUS_NEW PACKAGE_NA
------------------- ---------- ----------
               4755          3 呈批处理
               4836          3 公文处理

通过远程视图,接触数据类型发生改变异常(怀疑是dblink 在insert时候,char数据类型变成了number,但是未得到官方或者权威的确认)

RBA和实例恢复关系

1.关于heartbeat和checkpoint
在这次的删除过程中我没有执行commit,而是直接abort数据库。整个删除过程执行了近6分钟,控制文件的心跳每三秒进行一次,心跳是把low cache rba记录到了控制文件中,而没有真正的把全部的脏数据写入到磁盘( 只有发生了checkpoint时候,才会把相关的脏数据写入到磁盘,而这里的控制文件的heartbeat和checkpoint是两回事,checkpoint一般是在切换日志,数据文件正常离线,执行begin backup命令时发生,昨晚晚上后面的一个困惑就是上面的英文描述,让我把这两者搞混淆了)

2.三种rba解释
low rba :在buffer cache中的数据块第一次数据改变所对应的RAB。
high rba :在buffer cache中的数据块最近一次数据改变时所对应的RAB。
on-disk rba:是 lgwr 写日志文件的最末位置的地址。

3.实例恢复过程解释
实例恢复的时候,是从控制文件heartbeat记录的low rba开始读redo log数据(会多读取一点,因为heartbeat是每三秒执行一次,假设在2.9秒的时候,数据库异常down了,控制文件中记录的还是2.9秒前的low rba,这个时候,从该点开始读取redo),恢复到on-disk rba,而不是high rba(high rba一般情况下会大于on-disk rba,但是因为high rba比on-disk rba多的部分记录在redo log buffer中,在实例恢复的时候,因为其未被记录到redo log file中,所以不能被恢复,其实也没有必要恢复,因为该数据肯定是没有commit或者rollback)

具体内容和实验请见:RBA和实例恢复关系

ORA-600 kcratr_nab_less_than_odr故障解决

朋友的数据库服务器出现ORA-00600[kcratr_nab_less_than_odr],不能open数据库
1.open数据库报ORA-00600[kcratr_nab_less_than_odr]

SQL> ALTER DATABASE OPEN;
ALTER DATABASE OPEN
*
第 1 行出现错误:
ORA-00600: 内部错误代码, 参数: [kcratr_nab_less_than_odr], [1], [99189],
[43531], [43569], [], [], [], [], [], [], []

2.查看alert日志

Wed Jan 11 13:56:16 2012
ALTER DATABASE OPEN
Beginning crash recovery of 1 threads
 parallel recovery started with 2 processes
Started redo scan
Completed redo scan
 read 54591 KB redo, 0 data blocks need recovery
Errors in file d:\dbdms\diag\rdbms\dbdms\dbdms\trace\dbdms_ora_3108.trc  (incident=818557):
ORA-00600: 内部错误代码, 参数: [kcratr_nab_less_than_odr], [1], [99189], [43531], [43569], [], [], [], [], [], [], []
Incident details in: d:\dbdms\diag\rdbms\dbdms\dbdms\incident\incdir_818557\dbdms_ora_3936_i818557.trc
Aborting crash recovery due to error 600
Errors in file d:\dbdms\diag\rdbms\dbdms\dbdms\trace\dbdms_ora_3108.trc:
ORA-00600: 内部错误代码, 参数: [kcratr_nab_less_than_odr], [1], [99189], [43531], [43569], [], [], [], [], [], [], []
Errors in file d:\dbdms\diag\rdbms\dbdms\dbdms\trace\dbdms_ora_3108.trc:
ORA-00600: 内部错误代码, 参数: [kcratr_nab_less_than_odr], [1], [99189], [43531], [43569], [], [], [], [], [], [], []
ORA-600 signalled during: ALTER DATABASE OPEN...
Trace dumping is performing id=[cdmp_20120110214555]

3.查看trace文件

Trace file d:\dbdms\diag\rdbms\dbdms\dbdms\trace\dbdms_ora_3108.trc
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Windows NT Version V6.1 Service Pack 1 
CPU                 : 2 - type 8664, 2 Physical Cores
Process Affinity    : 0x0x0000000000000000
Memory (Avail/Total): Ph:2250M/4060M, Ph+PgF:5868M/8119M 
Instance name: dbdms
Redo thread mounted by this instance: 1
Oracle process number: 17
Windows thread id: 3108, image: ORACLE.EXE (SHAD)
…………………………
WARNING! Crash recovery of thread 1 seq 99189 is
ending at redo block 43531 but should not have ended before
redo block 43569
Incident 826550 created, dump file: d:\dbdms\diag\rdbms\dbdms\dbdms\incident\incdir_826550\dbdms_ora_3108_i826550.trc
ORA-00600: ??????, ??: [kcratr_nab_less_than_odr], [1], [99189], [43531], [43569], [], [], [], [], [], [], []

ORA-00600: ??????, ??: [kcratr_nab_less_than_odr], [1], [99189], [43531], [43569], [], [], [], [], [], [], []
ORA-00600: ??????, ??: [kcratr_nab_less_than_odr], [1], [99189], [43531], [43569], [], [], [], [], [], [], []

通过alert和trace中的内容可以知道,数据库需要恢复到rba到43569,但是因为某种原因实例恢复的时候,只能利用1 thread 99189 seq#,恢复rba到43531。从而导致数据库无法正常open

This Problem is caused by Storage Problem of the Database Files. 
The Subsystem (eg. SAN) crashed while the Database was open. 
The Database then crashed since the Database Files were not accessible anymore. 
This caused a lost Write into the Online RedoLogs and so Instance Recovery is not possible and raising the ORA-600.

4.解决方法

SQL> SELECT STATUS FROM V$INSTANCE;

STATUS
------------
MOUNTED

--尝试直接recover database
SQL> RECOVER DATABASE ;
ORA-00283: 恢复会话因错误而取消
ORA-00264: 不要求恢复
--提示不用恢复

--再打开数据库,还是kcratr_nab_less_than_odr错误警告
SQL> ALTER DATABASE OPEN;
ALTER DATABASE OPEN
*
第 1 行出现错误:
ORA-00600: 内部错误代码, 参数: [kcratr_nab_less_than_odr], [1], [99189],
[43531], [43569], [], [], [], [], [], [], []

--尝试不完全恢复
SQL> RECOVER DATABASE UNTIL CANCEL;
ORA-10879: error signaled in parallel recovery slave
ORA-01547: 警告: RECOVER 成功但 OPEN RESETLOGS 将出现如下错误
ORA-01152: 文件 1 没有从过旧的备份中还原
ORA-01110: 数据文件 1: 'D:\DBDMS\DATA\SYSTEM01.DBF'

--重建控制文件
SQL> ALTER DATABASE BACKUP CONTROLFILE TO TRACE AS 'D:/1.TXT';

数据库已更改。

SQL> SHUTDOWN IMMEDIATE;
ORA-01109: 数据库未打开


已经卸载数据库。
ORACLE 例程已经关闭。
SQL> STARTUP NOMOUNT;
ORACLE 例程已经启动。

Total System Global Area  417546240 bytes
Fixed Size                  2176328 bytes
Variable Size             268438200 bytes
Database Buffers          138412032 bytes
Redo Buffers                8519680 bytes
SQL> CREATE CONTROLFILE REUSE DATABASE "DBDMS" NORESETLOGS  NOARCHIVELOG
  2      MAXLOGFILES 16
  3      MAXLOGMEMBERS 3
  4      MAXDATAFILES 100
  5      MAXINSTANCES 8
  6      MAXLOGHISTORY 18688
  7  LOGFILE
  8    GROUP 1 'D:\DBDMS\LOG\REDO01.LOG'  SIZE 50M BLOCKSIZE 512,
  9    GROUP 2 'D:\DBDMS\LOG\REDO02.LOG'  SIZE 50M BLOCKSIZE 512,
 10    GROUP 3 'D:\DBDMS\LOG\REDO03.LOG'  SIZE 50M BLOCKSIZE 512
 11  DATAFILE
 12    'D:\DBDMS\DATA\SYSTEM01.DBF',
 13    'D:\DBDMS\DATA\SYSAUX01.DBF',
 14    'D:\DBDMS\DATA\RBSG01.DBF',
 15    'D:\DBDMS\DATA\DATA01.DBF',
 16    'D:\DBDMS\DATA\INDX01.DBF',
 17    'D:\DBDMS\DATA\DATA02.DBF',
 18    'D:\DBDMS\DATA\DATA03.DBF',
 19    'D:\DBDMS\DATA\DATA04.DBF',
 20    'D:\DBDMS\DATA\INDX02.DBF',
 21    'D:\DBDMS\DATA\SYSTEM02.DBF'
 22  CHARACTER SET ZHS16GBK
 23  ;

控制文件已创建。

--继续尝试恢复
SQL> RECOVER DATABASE ;
完成介质恢复。
SQL> ALTER DATABASE OPEN;

数据库已更改。
--open成功

在这次恢复中,主要就是重建控制文件,然后直接恢复成功,如果redo有损坏,那么可能需要使用不完全恢复,然后使用resetlogs打开数据库

CAST本质探讨

1.试验前提

SQL> select * from v$version;

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
PL/SQL Release 11.2.0.3.0 - Production
CORE    11.2.0.3.0      Production
TNS for Linux: Version 11.2.0.3.0 - Production
NLSRTL Version 11.2.0.3.0 - Production

SQL> select FORCE_LOGGING,SUPPLEMENTAL_LOG_DATA_PK,SUPPLEMENTAL_LOG_DATA_UI,
   2 SUPPLEMENTAL_LOG_DATA_MIN from v$database;

FOR SUP SUP SUPPLEME
--- --- --- --------
NO  NO  NO  NO

SQL> conn / as sysdba
Connected.
SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /opt/oracle/oradata/archivelog/chf
Oldest online log sequence     1879
Next log sequence to archive   1881
Current log sequence           1881

SQL> select count(*) from t_xifenfei_move;

  COUNT(*)
----------
   7432085

SQL> select bytes/1024/1024 from user_segments where segment_name='T_XIFENFEI_MOVE';

BYTES/1024/1024
---------------
            832

从上面信息可以看到数据库处于归档模式,强制日志和辅助日志为开启,试验测试表t_xifenfei_move有7432085条记录,占用硬盘空间832M

2.常规CAST

SQL>  alter system flush buffer_cache;

System altered.

SQL> alter system flush shared_pool;

System altered.

SQL> SET TIMING ON
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                            100028
undo change vector size                                               16172

Elapsed: 00:00:00.06
SQL> create table chf.t_xifenfei_move_CAST tablespace users
  2  as
  3  select * from chf.t_xifenfei_move;
 
Table created.

Elapsed: 00:01:58.10
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                         873150548
undo change vector size                                              131384

Elapsed: 00:00:00.01

SQL> select 873150548-100028 "redo size" from dual;

 redo size
----------
 873050520

SQL> select 131384-16172 "undo size" from dual;

 undo size
----------
    115212

通过这个可以得出结论,产生redo为873050520,undo为115212

3.普通INSERT

SQL>  alter system flush buffer_cache;

System altered.

Elapsed: 00:00:00.06
SQL> alter system flush shared_pool;

System altered.

Elapsed: 00:00:00.01
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                               732
undo change vector size                                                 136

Elapsed: 00:00:00.18
SQL> CREATE TABLE t_xifenfei_move_INSERT 
  2  AS
  3  SELECT * FROM T_XIFENFEI_MOVE WHERE 1=0;

Table created.

Elapsed: 00:00:00.32
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                             22712
undo change vector size                                                6512

Elapsed: 00:00:00.02
SQL> INSERT INTO t_xifenfei_move_INSERT
  2  SELECT * FROM T_XIFENFEI_MOVE;

7432085 rows created.

Elapsed: 00:01:59.47
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                         862261580
undo change vector size                                            27980508

--redo 
SQL> select 22712-732 "create redo size" from dual;

create redo size
----------------
           21980

SQL> select 862261580-22712 "insert redo size" from dual;

insert redo size
----------------
       862238868

--undo
SQL> select 6512-136 "create undo size" from dual;

create undo size
----------------
            6376

SQL> select 27980508-6512 "insert undo size" from dual;

insert undo size
----------------
        27973996

通过这个可以得出CREATE TABLE 过程中产生redo:21980,undo:6376,而INSERT 过程中产生的redo:862238868,undo:27973996,整个过程总的产生redo:862260848(862238868+21980),undo:27980372(27973996+6376)

4.INSERT+APPEND

SQL>  alter system flush buffer_cache;

System altered.

Elapsed: 00:00:25.19
SQL> alter system flush shared_pool;

System altered.

Elapsed: 00:00:00.04
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                               732
undo change vector size                                                 136

Elapsed: 00:00:00.05
SQL> create table chf.t_xifenfei_move_INSERT_A tablespace users
  2  as
  3  select * from chf.t_xifenfei_move where 1=0;

Table created.

Elapsed: 00:00:00.18
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                             21892
undo change vector size                                                6308

Elapsed: 00:00:00.00
SQL> INSERT /*+ append */INTO t_xifenfei_move_INSERT_A
  2  SELECT * FROM T_XIFENFEI_MOVE;

7432085 rows created.

Elapsed: 00:02:26.37
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                         872792032
undo change vector size                                               87764

--redo
SQL> select 21892-732 "create redo size" from dual;

create redo size
----------------
           21160

SQL> select 872792032-21892 "insert redo size" from dual;

insert redo size
----------------
       872770140

--undo
SQL> select 6308-136 "create undo size" from dual;

create undo size
----------------
            6172

SQL> select 87764-6308 "insert undo size" from dual;

insert undo size
----------------
           81456

这个过程可以得到结论,create 表的过程产生的redo:21160,undo:6172;insert 表的过程redo:872770140,undo:81456;整个过程产生的redo:872791300(21160+872770140),undo:87628(6172+81456)

5.INSERT+NOLOGGING

SQL>  alter system flush buffer_cache;

System altered.

Elapsed: 00:00:02.21
SQL> alter system flush shared_pool;

System altered.

Elapsed: 00:00:00.06
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                               780
undo change vector size                                                 136

Elapsed: 00:00:00.06
SQL> create table chf.t_xifenfei_move_INSERT_N tablespace users
  2  as
  3  select * from chf.t_xifenfei_move where 1=0;

Table created.

Elapsed: 00:00:00.22
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                             22056
undo change vector size                                                6308

Elapsed: 00:00:00.00
SQL> INSERT /*+ NOLOGGING */INTO t_xifenfei_move_INSERT_N
  2  SELECT * FROM T_XIFENFEI_MOVE;

7432085 rows created.

Elapsed: 00:02:30.33
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                         862123984
undo change vector size                                            27982876

--redo
SQL> select 22056-780 "create redo size" from dual;

create redo size
----------------
           21276

SQL> select 862123984-22056 "insert redo size" from dual;

insert redo size
----------------
       862101928

--undo
SQL> select 6308-136 "create undo size" from dual;

create undo size
----------------
            6172

SQL> select 27982876-6308 "insert undo size" from dual;

insert undo size
----------------
        27976568

这个试验过程得出,create table得到redo:21276,undo:6172,insert table 得到redo:862101928,undo:27976568,整个过程redo:862123204,undo:27982740(27976568+6172)

6.INSERT+NOLOGGING(TABLE)

SQL>  alter system flush buffer_cache;

System altered.

Elapsed: 00:00:23.68
SQL> alter system flush shared_pool;

System altered.

Elapsed: 00:00:00.04
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                               800
undo change vector size                                                 136

Elapsed: 00:00:00.18
SQL> create table chf.t_xifenfei_move_INSERT_N_new nologging tablespace users
  2  as
  3  select * from chf.t_xifenfei_move where 1=0;

Table created.

Elapsed: 00:00:00.71
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                             23296
undo change vector size                                                6756

Elapsed: 00:00:00.00
SQL> INSERT INTO t_xifenfei_move_INSERT_N_new
  2  SELECT * FROM T_XIFENFEI_MOVE;

7432085 rows created.

Elapsed: 00:02:37.51
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                         862031304
undo change vector size                                            27982776

SQL> select 23296-800 "create redo size" from dual;

create redo size
----------------
           22496

SQL> select 862031304-23296 "insert redo size" from dual;

insert redo size
----------------
       862008008

SQL> select 6756-136 "create undo size" from dual;

create undo size
----------------
            6620

SQL> select 27982776-6756 "insert undo size" from dual;

insert undo size
----------------
        27976020

通过该试验得出,create table 产生redo:22496,undo:6620;insert into 产生redo:862008008,undo:27976020;整个过程产生redo:862030504(22496+862008008),undo:27982640(6620+27976020)

7.APPEND+NOLOGGING(TABLE)

SQL> alter system flush buffer_cache;

System altered.

Elapsed: 00:00:23.59
SQL> alter system flush shared_pool;

System altered.

Elapsed: 00:00:00.05
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                               780
undo change vector size                                                 136

Elapsed: 00:00:00.04
SQL> create table chf.t_xifenfei_move_INSERT_NA nologging tablespace users
  2  as
  3  select * from chf.t_xifenfei_move where 1=0;

Table created.

Elapsed: 00:00:00.42
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                             22000
undo change vector size                                                6308

Elapsed: 00:00:00.00
SQL> INSERT /*+APPEND */ INTO t_xifenfei_move_INSERT_NA
  2  SELECT * FROM T_XIFENFEI_MOVE;

7432085 rows created.

Elapsed: 00:01:08.92
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                            602352
undo change vector size                                               82756

--redo
SQL> select 22000-780 "create redo size" from dual;

create redo size
----------------
           21220

SQL> select 602352-22000 "insert redo size" from dual;

insert redo size
----------------
          580352

--undo
SQL> select 6308-136 "create undo size" from dual;

create undo size
----------------
            6172

SQL> select 82756-6308 "insert undo size" from dual;

insert undo size
----------------
           76448

在这个试验中,create table产生redo:21220,undo:6172,insert into产生redo:580352,undo:76448;整个过程产生的redo:601572(
21220+580352),undo:82620(6172+76448)

8.CAST+NOLOGGING(TABLE)

SQL>  alter system flush buffer_cache;

System altered.

Elapsed: 00:00:03.35
SQL> alter system flush shared_pool;

System altered.

Elapsed: 00:00:00.04
SQL> 
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                               732
undo change vector size                                                 136

Elapsed: 00:00:00.05
SQL> create table chf.t_xifenfei_move_cast_N nologging tablespace users
  2  as
  3  select * from chf.t_xifenfei_move;

Table created.

Elapsed: 00:00:56.41
SQL> select a.name, b.value
  2  from v$statname a, v$mystat b
  3  where a.statistic# = b.statistic#
  4  and lower(a.name) in
  5  ('redo size','undo change vector size');

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
redo size                                                            769848
undo change vector size                                              124944

SQL> select 769848-732 "redo size" from dual;

 redo size
----------
    769116

SQL> select 124944-136 "undo  size" from dual;

undo  size
----------
    124808

这个试验产生的redo:769116,undo:124808

9.通过试验得出结论
1)sql hint中的nologgging无效
2)普通的cast(不含hint),其本质是append,无nologgging
3)nologgging(表级别)可以使得cast效率较高
4)nologgging(表级别)+append(hint)可以使得insert效率较高