大表海量数据的转移及索引创建的记录

为了减少对于生产环境的影响，我们将大表的数据分配迁移到测试机上进行处理，然后在转移回生产库。

这将极大的减少对于生产库的影响和冲击，以下是略微记录一下这些转移处理的时间。
使用如下命令来导入一个分区的数据：
nohup time imp sms/sms file=smsmg_p1.dmp fromuser=sms touser=sms buffer=500000000 commit=yes feedback=100000 indexes=no ignore=yes &

通过输出得到如下信息，在一台2CPU 8 Core的Pc Server上，导入这1.3亿左右的数据，花费了109分钟左右的时间：

Import: Release 10.2.0.2.0 - Production on Thu Sep 17 22:00:20 2009

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


Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - Production
With the Partitioning, OLAP and Data Mining options

Export file created by EXPORT:V10.02.01 via conventional path

Warning: the objects were exported by SMS, not by you

import done in ZHS16GBK character set and UTF8 NCHAR character set
export server uses AL16UTF16 NCHAR character set (possible ncharset conversion)
. importing SMS's objects into SMS
. . importing partition            "SMSMG":"M01"
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                                                    135587487 rows imported

IMP-00057: Warning: Dump file may not contain data of all partitions of this table
Import terminated successfully with warnings.

real    108m54.959s
user    31m4.134s
sys     3m7.302s

然后为这个表创建了一个Local的局部索引，又用去了37分钟：

SQL> set timing on
SQL> create index idx_MDN on smsmg(MDN) local nologging parallel 4;
Index created.

Elapsed: 00:37:29.64

这就是转移的好处，在生产库上，是无法创建和调整索引的，也不能使用并行，怕影响到生产的性能。
处理器摘要信息供参考：

processor       : 7
vendor_id       : GenuineIntel
cpu family      : 15
model           : 2
model name      : Intel(R) Xeon(TM) MP CPU 3.00GHz
stepping        : 6
cpu MHz         : 2990.724
cache size      : 512 KB
physical id     : 3
siblings        : 2
core id         : 3
cpu cores       : 1
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 2
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic
bogomips        : 5979.92

-The End-