presto-raptor-legacy/src/main/java/io/prestosql/plugin/raptor/legacy/RaptorBucketFunction.java/RaptorBucketFunction/getHashFunction
class RaptorBucketFunction:    private static HashFunction getHashFunction(Type type)
    {
        if (type.equals(BIGINT)) {
            return bigintHashFunction();
        }
        if (type.equals(INTEGER)) {
            return intHashFunction();
        }
        if (isVarcharType(type)) {
            return varcharHashFunction();
        }
        throw new PrestoException(NOT_SUPPORTED, "Bucketing is supported for bigint, integer and varchar, not " + type.getDisplayName());
    }