一、问题概述
在进行数据库例行维护时，遇到数据库正常导出，但导入时遇到有张表不能导入的问题。这张表存储工艺路线，大约共有160万条记录。表的不能导入影响一部分功能的实现，各单位反映强烈。
数据库系统：oracle 10.2.0.1 64bit for linux
操作系统：redhat 4 64bit

二、初步分析
首先排除是系统bug所带来的问题，因为前期导入导出未发现问题；另外由于是对同一数据库进行的导入导出，也排除了字符集问题。
单独再次导入此表，出现错误如下；
[oracle@zhx25 ~]$ imp system/ceshi fromuser=dba_mgr touser=dba_mgr tables=t_routdef ignore=y file=1.dmp
Import: Release 10.2.0.1.0 - Production on Tue Mar 18 14:19:49 2008
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
Export file created by EXPORT:V10.02.01 via conventional path
import done in ZHS16GBK character set and ZHS16GBK NCHAR character set
. importing DBA_MGR's objects into DBA_MGR
. . importing table "T_ROUTDEF"
IMP-00058: ORACLE error 1438 encountered
ORA-01438: value larger than specified precision allowed for this column
IMP-00028: partial import of previous table rolled back: 20501 rows rolled back
解决方向：有可能是数据中存在问题，很有可能是输入一些特殊字符，这些字符和ORACLE自身使用的通配符一致，所以导致系统不能识别。

三、问题解决
1、对问题进行跟踪
对系统设置1438 errorstack跟踪：
SQL> alter system set events='1438 trace name Errorstack forever,level 10';
System altered
然后重新执行IMP；

2、查看UDUMP下日志,如下:
/opt/oracle/admin/orcl/udump/orcl_ora_32355.trc
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
ORACLE_HOME = /opt/oracle/product/10.2.0
System name:Linux
Node name:zhx25.cccc.com
Release:2.6.9-22.ELsmp
Version:#1 SMP Mon Sep 19 18:00:54 EDT 2005
Machine:x86_64
Instance name: orcl
Redo thread mounted by this instance: 1
Oracle process number: 17
Unix process pid: 32355, image: mailto:oracle@zhx25.cccc.com]oracle@zhx25.cccc.com (TNS V1-V3)
*** SERVICE NAMESYS$USERS) 2008-03-18 17:11:02.014
*** SESSION ID135.949) 2008-03-18 17:11:02.014
*** 2008-03-18 17:11:02.014
ksedmp: internal or fatal error
ORA-01438: value larger than specified precision allowed for this column
Current SQL statement for this session:
INSERT /*+NESTED_TABLE_SET_REFS+*/ INTO "T_ROUTDEF" ("PRTNO", "SEQNO", "SEQDESC", "PRTEFLAG", "SEQCC", "SEQNXTNO", "SEQDEPT", "WKCCODE", "WKCALTCODE", "SEQSETHR", "LAB_SEQSETHR", "SEQRUNHR", "LAB_SEQRUNHR", "SEQQUEHR", "LAB_SEQQUEHR", "SEQTRANHR", "LAB_SEQTRANHR", "SEQNOQLTRAT", "SEQCHGDAT", "SEQCHGRSN", "SEQCHGCTLR", "MACHCODE", "MACHALTCODE", "RESCODE", "KEYSEQ", "SEQCRYLOT", "INITOVERRATE", "COMWORK", "SEQLOTFLAG", "SEQEFDAT", "SEQIEFDAT", "SEQEFLOTNO", "SEQIEFLOTNO", "SEQECONO", "PRTSEQCST", "SEQSELFCST", "INVYORN", "SEQQTY", "SEQNOTE", "NOPRTAVELZ", "OUTSEQFLAG", "WXCST", "SEQGSCHGCTLR", "SEQGSCHGDAT", "SEQSHCTL", "SEQSHDAT", "SEQSHSIGN", "PRICE", "ACCNO", "ROUSTAT", "FIXMFLAG", "BANCL" VALUES (:1, :2, :3, :4, :5, :6, :7, :8, :9, :10, :11, :12, :13, :14, :15, :16, :17, :18, :19, :20, :21, :22, :23, :24, :25, :26, :27, :28, :29, :30, :31, :32, :33, :34, :35, :36, :37, :38, :39, :40, :41, :42, :43, :44, :45, :46, :47, :48, :49, :50, :51, :52)
----- Call Stack Trace -----
calling
call
entry
argument values in hex
location
type
point
(? means dubious value)

…………

oacdef = 6a9477a0
Offsi = 48, Offsi = 1440
Opcode = 2
Bind Twotask Scalar Sql In (may be out) Copy
oacdef = 6a9477d0
Offsi = 48, Offsi = 1472
Opcode = 2
Bind Twotask Scalar Sql In (may be out) Copy
oacdef = 6a947800
Offsi = 48, Offsi = 1504
Opcode = 2
Bind Twotask Scalar Sql In (may be out) Copy
oacdef = 6a947830
Offsi = 48, Offsi = 1536
Opcode = 2
Bind Twotask Scalar Sql In (may be out) Copy
oacdef = 6a947860
Offsi = 48, Offsi = 1568
Opcode = 2
Bind Twotask Scalar Sql In (may be out) Copy
oacdef = 6a947890
Offsi = 48, Offsi = 1600
Opcode = 2
Bind Twotask Scalar Sql In (may be out) Copy
oacdef = 6a9478c0
Offsi = 48, Offsi = 1632
kkscoacd
Bind#0
oacdty=01 mxl=32(24) mxlc=00 mal=00 scl=00 pre=00
oacflg=03 fl2=1000010 frm=01 csi=852 siz=3344 off=0
kxsbbbfp=2a974dc398
bln=32
avl=23
flg=05
value="?

Bind#1
oacdty=02 mxl=22(22) mxlc=00 mal=00 scl=00 pre=00
oacflg=03 fl2=1000000 frm=00 csi=00 siz=0 off=32
kxsbbbfp=2a974dc3b8
bln=22 avl=22 flg=01
value=###
An invalid number has been seen.Memory contents are :
Dump of memory from 0x0000002A974CDE88 to 0x0000002A974CDE9E
2A974CDE80 3331312E 0406C102 [.113....]
2A974CDE90 C9BBC6C8 52024D01 30310248 00003304[.....M.RH.10.3..]
Bind#2
oacdty=01 mxl=32(30) mxlc=00 mal=00 scl=00 pre=00
oacflg=03 fl2=1000010 frm=01 csi=852 siz=0 off=56
kxsbbbfp=2a974dc3d0
bln=32
avl=00
flg=01
Bind#3
oacdty=01 mxl=32(01) mxlc=00 mal=00 scl=00 pre=00
oacflg=03 fl2=1000010 frm=01 csi=852 siz=0 off=88
kxsbbbfp=2a974dc3f0
bln=32
avl=01
flg=01
value="M"
…………
从跟踪文件可以看到，问题是系统认为地址为2A974CDE88的数值非法，在导入会提示ora-1438错误。本值在数据库中定义为number(8)类型，但从结果来看，系统把这个值当成了number(24)类型，并且由于格式不对，不能取出值。

3、找到DMP中相关数据
用winhex打开dmp文件，搜索十六进制串“2E313133 02C10604 C8C6BBC9 014D0252 48023130 0433F3FF”（对trace文件中的值要进行顺序调整），结果如下图：

4、对导出数据进行更改
由于“2E313133 02C10604 C8C6BBC9 014D0252 48023130 0433F3FF”不是一个有效的number类型，需要对它进行调整。调整如下，只要确保调整的值是number类型的即可。

5、对数据库相关数据项的类型进行调整
把数据项的类型由number(*)改为number(38)；

6、重新进行数据导入
[oracle@zhx25 ~]$ imp system/ceshi fromuser=dba_mgr touser=dba_mgr tables=t_routdef ignore=y file=1.dmp
Import: Release 10.2.0.1.0 - Production on Tue Mar 18 14:19:49 2008
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
Export file created by EXPORT:V10.02.01 via conventional path
import done in ZHS16GBK character set and ZHS16GBK NCHAR character set
. importing DBA_MGR's objects into DBA_MGR
. . importing table
"T_ROUTDEF"
1646404
导入成功。