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Handling 1M websocket connections in Go

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Re: Handling 1M websocket connections in Go

#61

Post by ponyous »

brightball wrote: post #7
cuddlecake wrote: post #2

Can someone make a comparison between this and the Elixir Phoenix 2m websocket conmections example. I want to sleep.

I remember seeing a talk on the 2m websocket Elixir example and one of the keys to it was that the sockets were actually being used and processing messages intermittently during the test. Important thing to keep in mind vs simply opening. The other thing I'd be interested to see Elixir demonstrate would be doing a hot deployment to avoid triggering all 2m connections to try reconnect at the same time. The other impor…

I did hot code upgrades on a server with WS connections active and I don't remember connections being broken.

Re: Handling 1M websocket connections in Go

#62

Post by mateuszf »

pmlopes wrote: post #52
mateuszf wrote: post #25

Earlier quoted context omitted.

Jvm is very optimized, so it's actually something not that non-special.

> "so it's actually something not that non-special." That is not totally true, This is a mix of 2 things, using the JVM (which like you said is being tuned and optimized for heavy loads) + using a true asynchronous and reactive programming (and IO) model built on great technologies such as (in this specific case: Kotlin, Eclipse Vert.x and Netty). As an experiment if you would pick another random set of libraries (im…

That's why I used not two times. I meant that it IS special, sorry for confusion, I'm not a native speaker.

Re: Handling 1M websocket connections in Go

#64

Post by rhizome »

kjksf wrote: post #29
rhizome wrote: post #19

I'd like to see this kind of story combined with the "how to build a business" threads to discuss what kinds of business models and sizes require a million websocket connections to one process. 1M simultaneous users of a React (or other) app, is that a decently simple case? What are some sites that have this level of activity? I found a 5yr old article that says Spotify had 20MM simultaneous users then, but spread ov…

One of their slides ( https://speakerdeck.com/eranyanay/going-infinite-handling-1m... ) lists the use cases for such functionality and they are pretty broad (message queues, chat apps, notifications, social feeds, collaborative editing, location updates). When you consider the price of the hardware and complexity of the system, it's obviously useful not just for handling 1M connections per host but also 10k connectio…

Sure, I can imagine all kinds of websocket applications and their economic tradeoffs, just not ones that have ever enjoyed a million connections against a single server instance.

Re: Handling 1M websocket connections in Go

#65

Post by fulafel »

kjksf wrote: post #32
jondubois wrote: post #15

These kinds of benchmarks are not very meaningful. I think that pretty much any modern framework/language can handle at least 1 million idle WebSockets. It's much more interesting to measure performance when you start sending messages through them at regular intervals.

When people rewrite system from X where X in (Python, Ruby, Node, Clojure) to Go they usually see at least 10x improvement. This is just one recent example: https://www.infoq.com/articles/api-gateway-clojure-golang The money quote: "The end result enabled us to reduce 25 instances (c4 xlarge) running Clojure code - able to process 60 concurrent requests, to two instances (c3.2xlarge) running Go code able to support ~…

Hmm, there's a slight disparity between the quote and their benchmark table, which shows Clojure and Go neck and neck in the request/sec dept. I guess all the system re-architecting explains most of the difference.

In any case, as the article text also mentions, on the Go side they are using a complete reverse-proxy library that's included with the Go stdlib, which can be a significant advantage aside from the properties of the language itself.

But then it seems they ended up reimplementing many things that the JVM provides: "In order to achieve out of the box functionality such as CPU and memory usage metrics, business logic counters and more - we needed to write basically this entire stack from scratch, which enabled us a much more rapid deep dive of the intricacies of Golang."

Re: Handling 1M websocket connections in Go

#66

Post by Casperin »

zensavona wrote: post #51
brightball wrote: post #7

Earlier quoted context omitted.

I remember seeing a talk on the 2m websocket Elixir example and one of the keys to it was that the sockets were actually being used and processing messages intermittently during the test. Important thing to keep in mind vs simply opening. The other thing I'd be interested to see Elixir demonstrate would be doing a hot deployment to avoid triggering all 2m connections to try reconnect at the same time. The other impor…

With Elixir/OTP there would be no disconnection/reconnection. The way hot code push works with OTP is that each "channel" (OTP "process"/websocket connection) has a GenServer, which is basically a state machine, and when there is a new version of the function available in the VM, the current state is passed into a function (supplied by you) to mutate it into a shape compatible with your new change, then next time the…

I recorded an example of what that looks like about a year ago https://www.youtube.com/watch?v=CZWMc2cXUAw -- I no longer work in Elixir, but this magic still kind of blows my mind.

Re: Handling 1M websocket connections in Go

#67

Post by zepolen »

toredash wrote: post #57
art0rz wrote: post #27

Earlier quoted context omitted.

I have written a 1mm+ simultaneous user websocket server for a second screen app for a well known talent TV show in Node. It was running on a single server (with failovers and redundancies of course) just fine, but 99% of the server was just broadcasting. The hard part is sending single messages to users with user-specific content.

Agree on the hard part. Fan out models like this with the same content is "easy". Getting unique content to specific users in an efficient way, in scale of 100.000 users plus, that's hard.

Do you have an example of this type of unique content?

Re: Handling 1M websocket connections in Go

#68

Post by toredash »

zepolen wrote: post #67
toredash wrote: post #57

Earlier quoted context omitted.

Agree on the hard part. Fan out models like this with the same content is "easy". Getting unique content to specific users in an efficient way, in scale of 100.000 users plus, that's hard.

Do you have an example of this type of unique content?

Quiz for instance with a leaderboard or prizing.

Let say you publish an Quiz to 1 mill users. Everyone response and you store the responses centrally. Now you send out an aggregated view of the results (e.g. % answered A).

Now, you want to inform one or more users that they won a prize. How do you do this effectively ?

Of better, you want to display the ranking to each user if there are multiple quiz.

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