Concurrent object locks based on ID field

Question

I have a producer/consumer process. The consumed object has an ID property (of type integer), I want only one object with the same ID to be consumed at a time. How can I perform this ?

Maybe I can do something like this, but I don't like it (too many objects created while only one or two with the same ID a day can be consumed and the lock(_lockers) is a bit time consuming :

    private readonly Dictionary<int,object> _lockers = new Dictionary<int,object>();
    private object GetLocker(int id)
    {
        lock(_lockers)
        {
            if(!_lockers.ContainsKey(id))
                _lockers.Add(id,new object());
            return _lockers[id];
        }
    }



    private void Consume(T notif)
    {
            lock(GetLocker(notif.ID))
           {
            ...
           }
    }

enter code here

NB : Same question with the ID property being of type string (in that cas maybe I can lock over the string.Internal(currentObject.ID)

Answer 1

Can you make your IDs to be unique for each object? If so, you could just apply a lock on the object itself.

Answer 2

As indicated in comment, one approach would be to have a fixed pool of locks (say 32), and take the ID modulo 32 to determine which lock to take. This would result in some false sharing of locks. 32 is number picked from the air - it would depend on your distibution of ID values, how many consumers, etc.