Out of memoryexception in SignalR due to a large real time data

Question

I'm using SignalR for a real time data ticker with up to 10k rows contained in a single object being sent to the client per sec. The memory of IIS worker processor goes on increasing until the ticking finally freezes.

Answer 1

First of all, as you already could read SignalR is built on a premise that you will not send large messages. However, in a real word it is a perfectly valid scenario.

So, what's the deal with a memory issues. SignalR has a circular buffer with a default size of 1000 elements, it stores every single message into that buffer per opened connection. So basically, if you have 100 opened connection, and you've sent 1000 messages it will be total of 100*1000 messages stored inside your memory.

Another thing you should take into consideration is .Net framework's large objects heap and garbage collection. Every object with a size greater than 85kB will went to the large object heap, next thing I should point out that garbage collector treats objects inside large object heap as a second generation objects. Taken that into account, you could realize that your objects once they have been dereferenced from the SignalR's circular buffer won't be garbage collected immediatelly due to their size.

As @davidfowl said, you really could make your data smaller, but sometimes you will not be able to do it, without introducing some pretty complex mechanic both on client and on server.

Fortunatelly, there is a way to reduce default size of SignalR's circular buffer, and you could do it by setting:

GlobalHost.Configuration.DefaultMessageBufferSize = 32