understanding of node js performance

Question

I recently discovered Node js and I read in various articles that Node js is fast and can handle more requests than a Java server although Node js use a single thread.

I understood that Node is based on an event loop, each call to a remote api or a database is done with an async call so the main thread is never blocked and the server can continue to handle others client requests.

If I understood well, each portion of code that can take times should be processed with an async call otherwise the server will be blocked and it won't be able to handle others requests ?

var server = http.createServer(function (request, response) {
   //CALL A METHOD WHICH CAN TAKE LONG TIME TO EXECUTE
   slowSyncMethod();
   //THE SERVER WILL STILL BE ABLE TO HANDLER OTHERS REQUESTS ??
   response.writeHead(200, {"Content-Type":"text/plain"});
   response.end("");
});

So if my understanding is correct, the above code is bad because the synchronous call to the slow method will block the Node js main thread ? Is Node js fast on condition that all the code that can take times are executed in an async manner ?

Answer 1

NodeJs is as fast as your hardware(vm) and the v8 that is running it. that being said, any heavy duty task like any type of media(music, image, video etc) file processing will definitively lock your application. so will computation on large collections thats why the async model is leveraged though events, and deferred invocations. that being said nothing stops you from spawning child processes to relegate heavy duty and asynchronously get back the result. But if you are finding your self in the need to do this for many tasks, maybe you should revisit your architecture. I hope thhis helps