Kudu exposes a type called UNIXTIME_MICROS that is essentially an int64 and is intended to store microseconds since the unix epoch. Impala has a TIMESTAMP type which differs significantly (an INT96 storing something based on boost's "date" and "time_duration" classes).
Users would like an Impala TIMESTAMP that works with Kudu, but this isn't feasible yet. For now, Impala will support creating Kudu tables with this underlying UNIXTIME_MICROS type but treating it otherwise as a BIGINT. In the future, Impala and Kudu will support a shared TIMESTAMP type. That work has yet to be planned.
For now, Impala will provide syntax in CREATE TABLE for Kudu tables to create integer columns with a hint (comment containing a specific string) that indicates to Impala to create the underlying column as a Kudu UNIXTIME_MICROS type, but the column is an integer as far as Impala is concerned. Kudu’s UNIXTIME_MICROS type is just a int64, so it will be read and returned as such. All operations in Impala, e.g. describe table, select stmts, insert stmts, etc., treat this column as a BIGINT (because to Impala it is).
Add support for hint in CREATE TABLE
Add support for hint in ALTER TABLE