def select_host_characteristics(self):
    """Select the characteristics of all the hosts.

    :return: Three dicts of hostnames to CPU MHz, cores, and RAM.
    """
    hosts_cpu_mhz = {}
    hosts_cpu_cores = {}
    hosts_ram = {}
    for x in self.hosts.select().execute().fetchall():
        hostname = str(x[1])
        hosts_cpu_mhz[hostname] = int(x[2])
        hosts_cpu_cores[hostname] = int(x[3])
        hosts_ram[hostname] = int(x[4])
    return hosts_cpu_mhz, hosts_cpu_cores, hosts_ram