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Don Burleson Blog 







ORA-12713 Character Data Loss NCHARCHAR Conversion

Expert Oracle Database Tips by Donald BurlesonApril 6, 2015


Question:  :  I am writing an RMAN backup and I get this ORA-12713 error:

RMAN-03009: failure of backup command on backup_1 channel at ...
ORA-12713: Character data loss in NCHAR/CHAR conversion Recovery Manager complete.

How do I fix the ORA-12713 error? 

Answer:   You start by using the oerr utility to look-up the action for this error:

 ORA-12713: Character data loss in NCHAR/CHAR conversion  

Cause: When character set conversion happens between CHAR and NCHAR either implicitly or explicitly, some characters are lost due to no mapping characters in the destination character set.

 Action: Make sure all the characters can be mapped to destination character set or set NLS_NCHAR_CONV_EXCP to be FALSE.    

In RMAN, the ORA-12713 error is usually an issue with the use of multi-byte character sets.

 Your backup is writing  to a disk that contains either extended ASCII and/or multi-byte character sets.   

In sum, those characters could not be successfully translated by RMAN, causing the ORA-12713 error.  

There are several solutions to the ORA-12713 error:

  •  Migrate from from US7ASCII to WE8MSWIN1252 using the using CONVERT() utility.  This will onvert you from  a narrow character set (eg UTF-8) to a wider set (UTF-16)

  •  Set your initialization parameter NLS_NCHAR_CONV_EXCP=FALSE

  •  Direct your RMAN to write backup files to a disk that only contains ASCII characters, the ORA-12713 will not happen.  

The Oracle documentation on Exception Handling for Data Loss During Datatype Conversion has full details on your conversion options:  

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