transaction rollback not working in django 1.6.5

[khaihkd]

Example:
my model: User (id: integer auto increment, name: string, age: integer)
I have a array data insert to database (database is mysql)
[['John', 20], ['Bob', 30], ['Mark', 'not number']]

@transaction.non_atomic_requests()
def update_Ac_Point_Detail(self):

array = [['John', 20], ['Bob', 30], ['Mark', 'not number']]
transaction.set_autocommit(False)
for item in array:

try:

user = User()
user.name = item[0]
user.age = item[1]
user.save()

except:

transaction.rollback()
return

transaction.commit()

When I check in database, it has 2 new records. it's not rollback.
Please help me. Thank you very much