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Realtime data streaming using server-sent events(SSE) with react.js and node.js

Peter Kelvin Torver on March 12, 2022

We live in a world where real-time data streaming has become paramount. Real-time data streaming has become a necessity in modern applications beca...

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Craig Aschbrenner • Apr 8 '22

Great article!

A couple of questions regarding SSEs...

Have you come across issues with the maximum number of connections (using http/1) as noted here? Or do you ensure http/2 is used?

Have you come across any limitations on the server for keeping connections open? I haven't been able to find much information on how many connections a server can keep open. I realize that's based on server hardware, number of instances, number of concurrent users, etc... but I've been trying to find a baseline number to compare.

Peter Kelvin Torver • Apr 9 '22

Thank you very much for asking this question. The max number(6) of connections indicated over there is per browser per domain. For instance with Google Chrome you can open 6 max number of connections to example.com and with ms edge you can still open another max connection of 6 to the same domain.
To answer your question;

The number of connections a server can handle is limitless and depending on the capacity of your hardware just like you stated.
What's indicated above is not possible in real life application because you can't just create 6 accounts on applications like twitter and login in this browser.
Using HTTP/1 is the one with such limit but using HTTP/2 should increase it upto 100 max connections per browser per domain.
The max number of connections indicated above is per browser per domain and not what your server can handle.

If you find anything worth sharing, please don't forget to share it with us. Thank you

Ana Maria Vergara Posada • Oct 18 '22

Hello,
The number of connections that the server support also depends on what web server you are using, for example, if you are using Apache, this formula gives you the number according to the hardware of your server:

(Total Memory – Critical Services Memory) / Size Per Apache process

It gives you the limit recommended for the Apache configuration, so your server will be optimized.