[dzik]

This article is quite good, especially part about bottleneck caused by single supervisor in ranch. However I have to say that title is a bit misleading because all of this has nothing to do with Elixir, it's all about Linux kernel and Erlang, cowboy and ranch are written in Erlang.

Having said that, I will add that I think it is good to have Elixir.

[keithnoizu]

And here i'm happy with my 8k requests per second Elixir IOT solution.

I use long lived processes and had to come up with some magic to work around the supervisor behavior with high child counts, etc.

Roughly I randomly assign worked to a node in the cluster if they have not yet been assigned. (there is some logic tracking total nodes on cluster and max / target that influences the decision). I verify if the remote (or local) worker is alive or migrating by checking a fragmented process Registry and unique identifier via :rpc (because I do some recovery logic if it's offline and let the caller specify if messages should force a spawn or can be ignored if the process is offline) and then pad the call with some meta information for rerouting so the receiver can confirm it is the same process the message was initially sent to (since processes cycle so frequently that the initial process may have died and a new process may have spawned in the time it took to forward the message).

If the process has changed mid transit or the worker has been flagged for migration the message gets rerouted to the new destination+process. If a process does not yet exist a hash based on the worker type + id and available worker pools is used to select which of the auto generated but named and registered (WorkType.PoolSupervisor_123) worker supervisors spawns the child node.

It's a trip, and needs to be heavily documented. Starting from scratch i'd probably change some things and it probably needs some refinement later this year before the next batch of 250-500k devices get added to the network, but the costs per reporting device are fantastic with plenty of low hanging fruit for improving the cogs further so I'm happy.

https://github.com/noizu/SimplePool/

[csisnett]

"is a bit misleading because all of this has nothing to do with Elixir" Stressgrid is written in elixir though, https://gitlab.com/stressgrid/stressgrid

[dzik]

Point taken and I am already looking at stressgrid, "millions of users" is definitely a selling point to me. It is actually quite hard to generate enough and correct traffic to stress test large distributed systems.

[dnautics]

Presumably they were using cowboy through Elixir. It's not hard, the module is just called :cowboy instead of cowboy.

[dqv]

Or `Cowboy` with `alias :cowboy, as: Cowboy` ;)

[latch]

Stick with the :module notation. This makes it clear that you need to be in "erlang mode"...indexes starting at 1, [probably] charlists instead of binaries, and possibly weird (from an elixir programmer's point of view) argument order.

[dnautics]

To be fair, it's a rare thing to be using an index in elixir at all.

[rdtsc]

That's fine I think. Elixir is their primary language it seems and using Erlang bits from Elixir is pretty easy, which is nice. It's a great benefit to the BEAM VM ecosystem. I think Elixir is the newer language and people enjoy up-voting it more. They could have said something like using BEAM VM and Cowboy maybe...? But I don't think it's a great misrepresentation either way.