I need to ask my client DBA to update the character set of the development database to AL32UTF8 character set. Currently they use some character sets which are very old.
How long it takes for a DBA to add this character set to the existing development database? Why Oracle recommends this Character Set for Customers?
Why AL32UTF8 is documented here - http://docs.oracle.com/cd/E11882_01/server.112/e25494/create001.htm#ADMIN13343
Converting the characterset of an existing database is not a trivial exercise - pl see
Depends on what data is in the database, what the source and target charactersets are, what your hardware and storage looks like etc - somewhere between 5 minutes and 5 weeks ;-)
You will have to test the conversion out on a hardware set up identical to production to come up with a estimate for your specific scenario
A more accurate estimate would be somewhere between 5 minutes and 5 years :-)
Please note that such migration has two phases: preparation and actual conversion. Actual conversion is usually a short process (depending on amount of non-ASCII and CLOB data in the database). But the preparation step is what may take months for a large production database. For an ASCII-only development database, this process should take much, much less. The time needed depends on how many issues prevent the successful conversion and how complex they are to fix. Take a look at the DMU documentation at http://docs.oracle.com/cd/E26101_01/welcome.html