Node.js servers are very efficient concerning I/O and large number of client connection. But why is node.js not suitable for heavy CPU apps in comparison to a traditional multithreading server?
I read it here Felix Baumgarten
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Node is, despite its asynchronous event model, by nature single threaded. When you launch a Node process, you are running a single process with a single thread on a single core. So your code will not be executed in parallel, only I/O operations are parallel because they are executed asynchronous. As such, long running CPU tasks will block the whole server and are usually a bad idea.
Given that you just start a Node process like that, it is possible to have multiple Node processes running in parallel though. That way you could still benefit from your multithreading architecture, although a single Node process does not. You would just need to have some load balancer in front that distributes requests along all your Node processes.
Another option would be to have the CPU work in separate processes and make Node interact with those instead of doing the work itself.
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