NodeJS JSON.stringify() bottleneck
My service returns responses of very large JSON objects - around 60MB. After some profiling I have found that it spends almost all of the time doing the JSON.stringify() call which is used to convert to string and send it as a response. I have tried custom implementations of stringify and they are even slower.
This is quite a bottleneck for my service. I want to be able to handle as many requests per second as possible - currently 1 request takes 700ms.
My questions are:
1) Can I optimize the sending of response part? Is there a more effective way than stringify-ing the object and sending the response?
2) Will using async module and performing the JSON.stringify() in a separate thread improve overall the number of requests/second(given that over 90% of the time is spent at that call)?
Answer
You've got two options:
1) find a JSON module that will allow you to stream the stringify operation, and process it in chunks. I don't know if such a module is out there, if it's not you'd have to build it. EDIT: Thanks to Reinard Mavronicolas for pointing out JSONStream in the comments. I've actually had it on my back burner to look for something like this, for a different use case.
2) async does not use threads. You'd need to use cluster or some other actual threading module to drop the processing into a separate thread. The caveat here is that you're still processing a large amount of data, you're gaining bandwidth using threads but depending on your traffic you still may hit a limit.