// protected methods
/// <summary>
/// Chooses the server instance.
/// </summary>
/// <param name="connectedInstances">The connected instances.</param>
/// <param name="readPreference">The read preference.</param>
/// <returns>A MongoServerInstance.</returns>
protected override MongoServerInstance ChooseServerInstance(ConnectedInstanceCollection connectedInstances, ReadPreference readPreference)
{
var instancesWithPingTime = connectedInstances.GetAllInstances();
if (instancesWithPingTime.Count == 0)
{
return(null);
}
else if (instancesWithPingTime.Count == 1)
{
return(instancesWithPingTime[0].Instance);
}
else
{
var secondaryAcceptableLatency = Settings.SecondaryAcceptableLatency;
var minPingTime = instancesWithPingTime[0].CachedAveragePingTime;
var maxPingTime = minPingTime + secondaryAcceptableLatency;
var n = instancesWithPingTime.Count(i => i.CachedAveragePingTime <= maxPingTime);
lock (_randomLock)
{
var index = _random.Next(n);
return(instancesWithPingTime[index].Instance); // return random instance
}
}
}
// protected methods
/// <summary>
/// Chooses the server instance.
/// </summary>
/// <param name="connectedInstances">The connected instances.</param>
/// <param name="readPreference">The read preference.</param>
/// <returns>A MongoServerInstance.</returns>
protected override MongoServerInstance ChooseServerInstance(ConnectedInstanceCollection connectedInstances, ReadPreference readPreference)
{
var instancesWithPingTime = connectedInstances.GetAllInstances();
if (instancesWithPingTime.Count == 0)
{
return null;
}
else if (instancesWithPingTime.Count == 1)
{
return instancesWithPingTime[0].Instance;
}
else
{
var minPingTime = instancesWithPingTime[0].CachedAveragePingTime;
var maxPingTime = minPingTime + readPreference.SecondaryAcceptableLatency;
var n = instancesWithPingTime.Count(i => i.CachedAveragePingTime <= maxPingTime);
lock (_randomLock)
{
var index = _random.Next(n);
return instancesWithPingTime[index].Instance; // return random instance
}
}
}