**Describe the situation**
```
$ ./clickhouse-21.3.3 client --query "SELECT * FROM system.numbers_mt FORMAT Native" | pv > /dev/null
^C,1GiB 0:00:45 [ 710MiB/s] [                                                                                                                                                                                               <=>                      ]

$ ./clickhouse-21.3.3 client --compress 0 --query "SELECT * FROM system.numbers_mt FORMAT Native" | pv > /dev/null
^C,2GiB 0:00:12 [1,48GiB/s] [                                                   <=>                                                                                                                                                                  ]
```

const Settings & settings,
                 const String & config_prefix_,
                 const String & cluster_name)
{
    auto config_prefix = config_prefix_ + "." + cluster_name;
    Poco::Util::AbstractConfiguration::Keys config_keys;
    config.keys(config_prefix, config_keys);
    config_prefix += ".";
    secret = config.getString(config_prefix + "secret", "");
    boost::range::remove_erase(config_keys, "secret");
    if (config_keys.empty())
        throw Exception("No cluster elements (shard, node) specified in config at path " + config_prefix, ErrorCodes::SHARD_HAS_NO_CONNECTIONS);
    UInt32 current_shard_num = 1;
    for (const auto & key : config_keys)
    {
        if (startsWith(key, "node"))
        {
            
            Addresses addresses;
            const auto & prefix = config_prefix + key;
            const auto weight = config.getInt(prefix + ".weight", default_weight);
            addresses.emplace_back(config, prefix, cluster_name, secret, current_shard_num, 1);
            const auto & address = addresses.back();
            ShardInfo info;
            info.shard_num = current_shard_num;
            info.weight = weight;
            if (address.is_local)
                info.local_addresses.push_back(address);
            ConnectionPoolPtr pool = std::make_shared<ConnectionPool>(