SetMaxConns and setMaxConnsPerHost in Astyanax client

I use Astyanax clientto read data from Cassandra database. I have single clusterwith four nodes. I have one replication factor of 2. I'm trying to understand what is the difference between

setMaxConns and setMaxConnsPerHost 

in an Astyanax client? I can not find the relevant documentation on this.

I have multi-threaded code that spawns multiple threads and then creates a connection to the Cassandra database only once (since it's Singleton) and then continues reusing for another request.

Now I'm trying to understand how these two methods will play a role in read performance? And how should these values ​​be configured?

And if I set these two methods above as -

setMaxConns(-1) and setMaxConnsPerHost(20) 

what does that mean? Any explanation would be very helpful.

Updated Code: -

, -

private CassandraAstyanaxConnection() {

    context = new AstyanaxContext.Builder()
    .forCluster(ModelConstants.CLUSTER)
    .forKeyspace(ModelConstants.KEYSPACE)
    .withAstyanaxConfiguration(new AstyanaxConfigurationImpl()      
        .setDiscoveryType(NodeDiscoveryType.RING_DESCRIBE)
    )
    .withConnectionPoolConfiguration(new ConnectionPoolConfigurationImpl("MyConnectionPool")
        .setPort(9160)
        .setMaxConnsPerHost(20)
        .setMaxConns(-1)
        .setSeeds("host1:9160,host2:9160,host3:9160,host4:9160")
    )
    .withAstyanaxConfiguration(new AstyanaxConfigurationImpl()      
        .setCqlVersion("3.0.0")
        .setTargetCassandraVersion("1.2"))
    .withConnectionPoolMonitor(new CountingConnectionPoolMonitor())
    .buildKeyspace(ThriftFamilyFactory.getInstance());

    context.start();
    keyspace = context.getEntity();

    emp_cf = ColumnFamily.newColumnFamily(
        ModelConstants.COLUMN_FAMILY, 
        StringSerializer.get(), 
        StringSerializer.get());
}

, BagOfConnectionsConnectionPoolImpl. , , . , .