presto-main/src/main/java/io/prestosql/connector/system/jdbc/ColumnJdbcTable.java/ColumnJdbcTable/numPrecRadix
class ColumnJdbcTable:    static Integer numPrecRadix(Type type)
    {
        if (type.equals(BIGINT) ||
                type.equals(INTEGER) ||
                type.equals(SMALLINT) ||
                type.equals(TINYINT) ||
                (type instanceof DecimalType)) {
            return 10;
        }
        if (type.equals(REAL) || type.equals(DOUBLE)) {
            return 2;
        }
        return null;
    }