/// <exception cref="System.Net.Sockets.SocketException">Throws a SocketException when the connection could not be established with the host</exception>
/// <exception cref="AuthenticationException" />
/// <exception cref="UnsupportedProtocolVersionException"></exception>
private Connection CreateConnection()
{
_logger.Info("Creating a new connection to the host " + Host.Address.ToString());
var c = new Connection(ProtocolVersion, Host.Address, Configuration);
c.Init();
if (Configuration.PoolingOptions.GetHeartBeatInterval() != null)
{
//Heartbeat is enabled, subscribe for possible exceptions
c.OnIdleRequestException += OnIdleRequestException;
}
return c;
}
/// <summary>
/// Gets the connection with the minimum number of InFlight requests.
/// Only checks for index + 1 and index, to avoid a loop of all connections.
/// </summary>
public static Connection MinInFlight(Connection[] connections, ref int connectionIndex)
{
if (connections.Length == 1)
{
return connections[0];
}
//It is very likely that the amount of InFlight requests per connection is the same
//Do round robin between connections, skipping connections that have more in flight requests
var index = Interlocked.Increment(ref connectionIndex);
if (index > ConnectionIndexOverflow)
{
//Overflow protection, not exactly thread-safe but we can live with it
Interlocked.Exchange(ref connectionIndex, 0);
}
var currentConnection = connections[index % connections.Length];
var previousConnection = connections[(index - 1)%connections.Length];
if (previousConnection.InFlight < currentConnection.InFlight)
{
return previousConnection;
}
return currentConnection;
}
public void CheckHealth(Connection c)
{
if (c.TimedOutOperations < _config.SocketOptions.DefunctReadTimeoutThreshold)
{
return;
}
//We are in the default thread-pool (non-io thread)
//Defunct: close it and remove it from the pool
_connections.Remove(c);
c.Dispose();
}
private void TransitionCreationTask(TaskCompletionSource<Connection[]> tcs, Connection[] result, Exception ex = null)
{
if (ex != null)
{
tcs.TrySetException(ex);
}
else if (result != null)
{
tcs.TrySetResult(result);
}
else
{
tcs.TrySetException(new DriverInternalError("Creation task must transition from a result or an exception"));
}
Interlocked.Exchange(ref _creationTcs, null);
}
/// <exception cref="System.Net.Sockets.SocketException">Throws a SocketException when the connection could not be established with the host</exception>
/// <exception cref="AuthenticationException" />
/// <exception cref="UnsupportedProtocolVersionException"></exception>
internal virtual Task<Connection> CreateConnection()
{
Logger.Info("Creating a new connection to the host " + _host.Address);
var c = new Connection(_serializer, _host.Address, _config);
return c.Open().ContinueWith(t =>
{
if (t.Status == TaskStatus.RanToCompletion)
{
if (_config.GetPoolingOptions(_serializer.ProtocolVersion).GetHeartBeatInterval() > 0)
{
//Heartbeat is enabled, subscribe for possible exceptions
c.OnIdleRequestException += OnIdleRequestException;
}
return c;
}
Logger.Info("The connection to {0} could not be opened", _host.Address);
c.Dispose();
if (t.Exception != null)
{
t.Exception.Handle(_ => true);
Logger.Error(t.Exception.InnerException);
throw t.Exception.InnerException;
}
throw new TaskCanceledException("The connection creation task was cancelled");
}, TaskContinuationOptions.ExecuteSynchronously);
}
/// <summary>
/// Gets the connection with the minimum number of InFlight requests
/// </summary>
public Connection MinInFlight(Connection[] connections)
{
if (connections.Length == 1)
{
return connections[0];
}
//It is very likely that the amount of InFlight requests per connection is the same
//Do round robin between connections
var list = new LinkedList<Connection>();
list.AddLast(connections[0]);
var lastValue = connections[0].InFlight;
for (var i = 1; i < connections.Length; i++)
{
var c = connections[i];
var inFlight = c.InFlight;
if (inFlight > lastValue)
{
continue;
}
if (inFlight == lastValue)
{
list.AddLast(c);
continue;
}
lastValue = inFlight;
list = new LinkedList<Connection>();
list.AddLast(connections[0]);
}
var index = Interlocked.Increment(ref _connectionIndex);
if (index > ConnectionIndexOverflow)
{
//Overflow protection, not exactly thread-safe but we can live with it
Interlocked.Exchange(ref _connectionIndex, 0);
}
return list.Skip(index % list.Count).First();
}
