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Solving Convertible or Lossy data in Data Dictionary objects reported by Csscan when changing the NLS_CHARACTERSET (Doc ID 258904.1)

Last updated on NOVEMBER 14, 2019

Applies to:

Oracle Database - Enterprise Edition - Version to [Release 8.0.3 to 11.2]
Oracle Database - Standard Edition - Version to [Release 8.0.3 to 11.2]
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Information in this document applies to any platform.


You are planning to convert the database character set from one character set to another set (for example to AL32UTF8) .

And you used Csscan and found some "Convertible" or "Lossy" in Data Dictionary objects and plan on using using ALTER DATABASE CHARACTER SET or Csalter. This note tries to give a overview of the most commonly seen "Convertible" and "Lossy" in Data Dictionary objects and how to handle these when using ALTER DATABASE CHARACTER SET / Csalter.

Note that "Convertible" in Data Dictionary objects is NOT a problem when using export/import into a new / other database.

A list of notes in changing the NLS_CHARACTERSET is provided in <Note 225912.1> Changing the Database Character Set ( NLS_CHARACTERSET )

Please do note that:
* Before changing the NLS_CHARACTERSET using Csalter or Alter Database..." it's mandatory to use Csscan. We strongly suggest to read <Note 444701.1> Csscan output explained
* some actions in this note use the csscan "exclude" option, the list of table NEEDS to be between ( ) and on most Unix shells it need  ' ' around the list of tables.
Example: on windows use EXCLUDE=(owner.table,owner.table) , on unix platforms use EXCLUDE='(owner.table,owner.table)'.
to avoid this one can use a parameter file for csscan, see <Note 444701.1> Csscan output explained , section " E) Do I need to always run a full database scan? / The Csscan EXCLUDE , USER or TABLE parameters do not appear to work."
* some selects in this note use the rowid 's stored by csscan in "data_rowid" column of the csmig.csmv$errors table, if such a select give "ORA-01410: invalid ROWID" then this simply means that since the csscan some rows where removed in the object scanned. If this happens simply re-scan the table in question.



Any DBA who has "Convertible" or "Lossy" in Data Dictionary objects while using ALTER DATABASE CHARACTER SET or Csalter.


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In this Document
 A) Useful Selects when using Csscan:
 A1) 8i and 9i only: Data Dictionary objects that need action when using Alter database character set.
 A2) 10g and up: Data Dictionary objects that need action when using Csalter
 A3) 10g and up: To have a list of User / Application Data that need action before using Csalter
 B) 9i ONLY: Handling convertible in SYS.JOB$, SYS.METASTYLESHEET and SYS.RULE$ in 9i :
 C)10g and up: Handling "Convertible" or "Lossy" in the NLSENV column of SYS.JOB$ or NLS_ENV of SYS.SCHEDULER$_JOB or SYS.SCHEDULER$_PROGRAM.
 D) Handling tables like SYS.WRI$_* and SYS.WRH$_*
 D2) To clear SYS.WRH$_SQLTEXT execute following steps:
 E) "Convertible" or "Lossy" in SYS.SOURCE$
 F) "Convertible" or "Lossy" in SYS.COM$
 G) "Convertible" or "Lossy" in SYS.HISTGRM$
 H) Orphaned DataPump tables
 I) MDSYS (Oracle Spatial) objects (mainly 9i).
 J) "Convertible" or "Lossy" in SYS.COL$
 K) "Convertible" or "Lossy" in SYS.TRIGGER$
 L) "Convertible" or "Lossy" in SYS.VIEW$
 M) "Convertible" or "Lossy" in SYSTEM.HELP
 N) "Convertible" or "Lossy" in TEXT column of SYS.ERROR$
 O) "Convertible" or "Lossy" in AUDIT column of SYS.SEQ$
 P) "Convertible" or "Lossy" in SYS.FGA_LOG$
 Q) "Convertible" or "Lossy" in SYS.REGISTRY$ERROR
 R) "Convertible" or "Lossy" in QUERY_TXT Column of SYS.REG_SNAP$
 S) "Convertible" or "Lossy" in the "DESCRIPTION " column of SYS.RESOURCE* tables
 T) "Convertible" or "Lossy" in PIECE Column of SYS.IDL_CHAR$
 U) "Lossy" in SESSION_KEY column of SYS.REG$ or SYS.REGZ$ :
 V) "Convertible" or "Lossy" in AUD$ 
 W) "Convertible" or "Lossy" in SCHEDULER$ table like SYS.SCHEDULER$_EVENT_LOG
 X) "Lossy" Data In OLAP_DESCRIPTIONS$ Table
 z) "Lossy" for XDB.XDB$COMPLEX_TYPE when doing  FROMCHAR=TOCHAR scan

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