Changing the Character Set for a RAC Database Fails with an ORA-12720


Changing the Character set for a RAC Database fails with below ORA-12720 error.

ORA-02374: conversion error loading table “RTLSDPROD”.”ZIF_CRANE_MSG_LOG”
ORA-12899: value too large for column MCHN_ID (actual: 11, maximum: 10)
ORA-02372: data for row: MCHN_ID : 0X’52880000603400006034′

The CLUSTER_DATABASE parameter must be temporarily changed in order  to alter the database character set. This will require a shutdown of the entire database (all instances).

Let’s do it step by step

Step 1: Shutdown all instances.

Step 2: On Node1, edit the initialization parameter CLUSTER_DATABASE and set it to FALSE


Step 3: Startup mount the instance in exclusive mode:

SQLPLUS> startup mount exclusive

Step 4: Issue the following commands:

alter system enable restricted session;
alter system set job_queue_processes = 0;
alter system set aq_tm_processes = 0;
alter database open;

Step 5: Change the character set.

Step 6: Shutdown the instance to enable parallel server.

SQLPLUS> shutdown immediate

Step 7: On Node1, edit the init.ora parameter CLUSTER_DATABASE  and set it to TRUE.


Step 8: Start up all the instances accessing the database.


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