according to this http://impala.io/overview.html, impala 2.1 should support nested data. I am using impala 2.1.1 but didn't find any documentation about nested data. Does anyone know when nested data will be supported by Impala?
Unfortunately Impala 2.1 does not support nested data. Note that the overview page you referenced lists these features under 'Impala 2.1 and Beyond'. We're currently working on it for an upcoming release this year.