Character Strings related : string_units db cfg changed from SYSTEM to CODEUNITS32
ALTER TABLE &lt;schema&gt;.&lt;tabname&gt; ALTER COLUMN &lt;colname&gt; SET DATA TYPE VARCHAR(20 CODEUNITS32);


The alter column set data type with CODEUNITS32 clause did the job.
If the string_units database configuration parameter is set to CODEUNITS32,
any new table without specifying this clause in column definition still works.

We have to perform the above alter only to the columns of existing table which was defined when string_units was set to default SYSTEM.

Hope it helps to other users.