EXP-00091: Exporting questionable statistics.

一.问题分析

      EXP时报这个错

[oracle@host01 ~]$ exp scott/tiger file=emp_dept.dmp tables=emp

Export: Release 11.2.0.3.0 - Production on Sun Jul 3 16:47:02 2016

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing o
Export done in US7ASCII character set and AL16UTF16 NCHAR character set
server uses AL32UTF8 character set (possible charset conversion)

About to export specified tables via Conventional Path ...
. . exporting table                            EMP         14 rows exported
EXP-00091: Exporting questionable statistics.
EXP-00091: Exporting questionable statistics.
Export terminated successfully with warnings.
[oracle@host01 ~]$

二.MOS查询

Error EXP-00091 While Taking Export (文档 ID 204793.1)

转到底部

---

APPLIES TO: Oracle Database - Enterprise Edition - Version 9.0.1.0 to 12.1.0.2 [Release 9.0.1 to 12.1] Information in this document applies to any platform. ***Checked for relevance on 13-Aug-2104*** SYMPTOMS You received errors: EXP-00091: Exporting questionable statistics during export. CAUSE Beginning with Oracle 9i by default export attempts to include statistics in the export. In pre-Oracle 9i versions statistics are not included unless it is specified. SOLUTION a. If the statistics of a table are not required to be included in export, then take the export with parameter STATISTICS=NONE. Example: #> exp scott/tiger file=emp1.dmp tables=emp STATISTICS=NONE b. In case, the statistics are need to be included, you can use STATISTICS=ESTIMATE or COMPUTE (default is Estimate). Note: The export will still generate the warning message about the questionable statistics in one of the following cases even if using STATISTICS=ESTIMATE / COMPUTE: 1. There are row errors while exporting 2. The client character set or NCHAR character set does not match the server character set or NCHAR character set (the NLS_LANG is different than the database character set for example). 3. A QUERY clause is specified 4. Only certain partitions or subpartitions are exported. The situation in case 2 is the most frequent and can be solved by setting the NLS_LANG character set of the client to the character set of the database. REFERENCES BUG:1862413 - EXPORT & DEFAULT FOR STATISTICS SHOULD BE PRE-9I COMPATIBLE NOTE:159787.1 - Import parameter: STATISTICS=SAFE

3.问题分析

    根据MOS和报错信息我们很明显看到这个报错是因为环境变量和数据库不一致或者环境变量未设置时导致的，因此有2种解决问题方案：

    1.> 设置不到出统计信息

    2.> 设置正确的环境变量（一般用这种方式）

4.问题解决

第一种解决方案：

[oracle@host01 ~]$ . profile_rac 
[oracle@host01 ~]$ echo $NLS_LANG

[oracle@host01 ~]$  exp system/sys file=emp_dept.dmp tables=scott.emp
Export: Release 11.2.0.3.0 - Production on Sun Jul 3 17:26:30 2016
Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing o
Export done in US7ASCII character set and AL16UTF16 NCHAR character set
server uses AL32UTF8 character set (possible charset conversion)
About to export specified tables via Conventional Path ...
Current user changed to SCOTT
. . exporting table                            EMP         14 rows exported
EXP-00091: Exporting questionable statistics.
EXP-00091: Exporting questionable statistics.
Export terminated successfully with warnings.
[oracle@host01 ~]$  exp system/sys file=emp_dept.dmp tables=scott.emp STATISTICS=NONE
Export: Release 11.2.0.3.0 - Production on Sun Jul 3 17:26:50 2016

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

Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing o
Export done in US7ASCII character set and AL16UTF16 NCHAR character set
server uses AL32UTF8 character set (possible charset conversion)
About to export specified tables via Conventional Path ...
Current user changed to SCOTT
. . exporting table                            EMP         14 rows exported
Export terminated successfully without warnings.
[oracle@host01 ~]$ 

第二种解决方案：

SQL> select * from v$nls_parameters where parameter='NLS_CHARACTERSET';

PARAMETER                           VALUE
----------------------------------------------------------------
NLS_CHARACTERSET                    AL32UTF8
SQL>

或者：

SQL> select * from nls_database_parameters t where t.parameter='NLS_CHARACTERSET';
PARAMETER             VALUE
--------------------------------------------------------------------
NLS_CHARACTERSET      AL32UTF8
SQL> 

[oracle@host01 ~]$ echo $NLS_LANG

[oracle@host01 ~]$ export NLS_LANG=AMERICAN_AMERICA.AL32UTF8
[oracle@host01 ~]$ echo $NLS_LANG
AMERICAN_AMERICA.AL32UTF8
[oracle@host01 ~]$ exp system/sys file=emp_dept.dmp tables=scott.emp
Export: Release 11.2.0.3.0 - Production on Sun Jul 3 17:23:50 2016
Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing o
Export done in AL32UTF8 character set and AL16UTF16 NCHAR character set

About to export specified tables via Conventional Path ...
Current user changed to SCOTT
. . exporting table                            EMP         14 rows exported
Export terminated successfully without warnings.
[oracle@host01 ~]$