We need a SQL type to match native Tarantool's 'integer' space format / index format type, which represents -2^63 .. 2^64-1 range of integral numbers. Those number are encoded as int64 or uint64 msgpack type depending of value.

Now we support the following integral number types in Tarantool/SQL: INT / INTEGER. SMALLINT and BIGINT intended to be supported after #3687.

There are the following ways to implement SQL type for the -2^63 .. 2^64-1 range:

1. Expand range for INT and INTEGER (it is now -2^63 .. 2^63-1). Expand BIGINT too. Don't sure about SMALLINT.
2. Expand BIGINT range, leave SMALLINT, INT, INTEGER as is.
3. Introduce a new SQL type, leave existing / planned integral SQL types as is.

I vote for the first way, because Tarantool/SQL type INTEGER is expected to represent the same range as native Tarantool's 'integer'.