EXPDP Export encountered ORA-39064: Could not write to log file

EXPDP Export encountered ORA-39064: Could not write to log file

. . . "USER_XXXX"."TAB_YYYY" 0 KB 0 line exported

ORA-39064: Unable to write to log file

ORA-29285: File write error

After searching for MOS, the following article gives a solution:
Error ORA-39064 might be encountered by DataPump Export (EXPDP) when Nls_lang are Different from Database Character Set (do C ID 1321034.1)

The solution given in this scenario is: Please set the character set in environment variable Nls_lang to database character set.

The following full text reproduces the MoS article and does not translate:

Applies To:

Oracle database-enterprise edition-version 10.1.0.2 and later

Information in this document applies to any platform.
Checked for relevance on 15-apr-2013***

Symptoms

In a multi-byte character set environment, if the client variable Nls_lang are set to a character set which is different FR Om Database The character set, then DataPump export could encounter errors like:

Ora-39064:unable to write to the log file

Ora-29285:file Write Error

The Utilities manual specifies:

Note:data Pump Export writes the log file using the database character set. If your client Nls_lang environment setting sets up a different client character set from the database character set and then It is possible this table names may be different in the log file than they was when displayed on the client output screen ."

Cause

This is investigated in bug 6136923 (closed as "not a Bug") with reference to unpublihsed documentation bug 3174256.

DataPump internally uses the package utl_file and this does not correctly return the characters during NLS conversion.

Solution

Please set the character set in environment variable Nls_lang to database character set.

The following information is added to manual:
Oracle Database PL/SQL Packages and Types Reference
Using Utl_file:
"When the data encoded in one character set was read and globalization support was told (such as by means of Nls_lang) that it I s encoded in another character set, and the result is indeterminate. If Nls_lang is set, it should be the same as the database character set. "

EXPDP Export encountered ORA-39064: Could not write to log file