Answer: In order to expand the
maximum value of varchar2 (also nvarchar2 and raw) datatypes
in Oracle 12c and beyond, the max_string_size
parameter needs to be set to "extended". This will
change the maximum value from 4k (4096) to 32k (32767).
Oracle will now support varchar2(32767) and raw (32767)
and nvarchar2(32767) (up from varchar2(4000).
Less than 4K is stored inline in the data blocks, and
more than 4K row lengths are stored out of
To change max_string_size from the default of
"standard" to "extended" you must bounce the database for
the parameter to take effect and then run a utility to
change all of the old maximum sizes for VARCHAR2 to the new
WARNING: You MUST run
utl32k.sql immediately after changing
max_string_size=extended, else you risk invalidating the
1. Start Oracle in UPGRADE mode
Connect AS SYSDBA
4. Change the setting of
MAX_STRING_SIZE to EXTENDED
5. Run $OH/rdbms/admin/utl32k.sql
6. Open the Oracle database.
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