is "ConnectionMultiplexer.IsConnected" expensive?

Question

In my caching AddItem and GetItem methods, I check if the connection to redis is alive or not before proceeding, is ConnectionMultiplexer.IsConnected an expensive method call? or should I just catch an exception and reconnect in that case?

Answer 1

Looking at ConnectionMultiplexer.IsConnected code:

public bool IsConnected
{
    get
    {
        var tmp = serverSnapshot;
        for (int i = 0; i < tmp.Length; i++)
            if (tmp[i].IsConnected) return true;
        return false;
    }
}

It seems like all work done here is going through server endpoints to see whether there is at-least one server endpoint connected.

Looking at ServerEndPoint.IsConnected code:

public bool IsConnected
{
    get
    {
        var tmp = interactive;
        return tmp != null && tmp.IsConnected;
    }
}

All work done here is returning interactive(of type PhysicalBridge) IsConnected value.

Looking at PhysicalBridge.IsConnected code:

public bool IsConnected => state == (int)State.ConnectedEstablished;

You can see all work done here is return whether two int's are equal.

So it seems like very little work is done calling ConnectionMultiplexer.IsConnected property.