Concurrent Server Connections

Discussions center on challenges and strategies for handling large numbers of concurrent TCP/HTTP connections in web servers, including limits from file descriptors and resources, connection reuse, pooling, keep-alives, and scalability issues like C10k.

📉 Falling 0.5x DevOps & Infrastructure
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RAM C1024K RpcClient.java percona.com GP HN djangoproject.com TCP FortiGate HTTP connections connection tcp server finite concurrent handle load application number

Sample Comments

SergeAx Oct 18, 2025 View on HN

Wouldn't it consume the same number of connections on my server?

willcipriano Apr 15, 2024 View on HN

You'd have to hold a ton of connections open for 24 hours+

dharmab Oct 2, 2020 View on HN

Make sure you’re reusing connections. A lot of languages and libraries create a new connection for every request unless you explicitly manage a session or connection pool.

jrockway Mar 17, 2011 View on HN

Web servers are limited in the number of concurrent connections they can maintain (tubes aren’t big enough).This doesn't really make sense -- maintaining a TCP connection requires no "tubes"; the limit comes from finite state storage: a finite state table, a finite number of file descriptors, and a finite amount of RAM in which to store the application-level connection contexts. These numbers turn out to be Really Fucking Big, so this is probably not affecting your application unless

asdffdasasdf Jan 21, 2024 View on HN

their heuristics is probably looking for long time connections.. you're scaping by moving the client around

smadge Mar 11, 2016 View on HN

I think you can use https keep alive to only require one tcp connection.

infogulch Apr 15, 2025 View on HN

That's neat. Does it require 1 connection = 1 process to work? I don't see how you can have a long running server with this feature.

dtjohnnymonkey May 28, 2022 View on HN

You might run into this limitation more quickly if you are receiving connections via a load balancer.

dontlaugh Apr 13, 2025 View on HN

Even load balancers force you to have a frequent heartbeat all the way to the client for each connection.

mraza007 Jun 17, 2020 View on HN

Thanks for sharing this How do they handle the server load when they have so many concurrent connections