jaeyson

jaeyson

Do we have "ELI5" for Elixir here?

Not trying to add more mess here but, reddit has ELI5 but i wanted to know if it’s okay to ask Elixir-specific (or outside of it) in a similar style of questions? i.e. I’ve heard backpressure (i’ve just read that term via Elixir-lang blog Announcing GenStage) and how/why does one (ie. Elixir) approach this? I’ve read it but i cant wrap it in my head (newbie).

Most Liked

mafinar

mafinar

Now, to answer your question on back-pressure. Let me draw an analogy from an experience I actually had during our covid 19 vaccination.

So my wife and I went to get vaccinated at a centre. We parked the car and saw a queue being formed right outside, of people waiting to get vaccinated. That queue reached from the parking place up to this tent-like structure.

Some volunteers came, and asked for proof of location, health card information etc and input those information into their iPads. And while that was happening, another volunteer at the front of our queue (and as we will find out soon, at the back of another) asked for 10 people to get in. When our turn came, we went inside and faced a similar, “controlled” and on-demand queueing system, we get called in groups, we enter in groups, and get serviced, and exit the premise. While this felt like a lot of rules to be implemented, it did end up feeling “effective”. The doctors who were giving vaccines did not have a crowded hall, and that hall had low number of people, manageable and quickly emptiable. On the other hand, you never really waited too long at any of those buffers.

Now, think about the nature of this group act, from the “provider’s” (i.e. volunteers’ or doctors’) perspective, they are obviously fewer in numbers than us, and they can only take so many at a time, by giving them the calling capability, the capacity is being managed. The traffic (i.e. we who are waiting to get vaccinated) are parked and get serviced only when the persons responsible to process are capable of doing so, and it is not something we see (i.e. when the person before me finishes I can “just go”) but that process is hidden from us. and we get called in batches, and that batch number often has a connection with the provider numbers (if there are 4 doctors maybe a batch of 2*4 or 3*4?).

This description is based on my experience and may not have any resemblance at all with the actual process or statistics behind it but let’s convert this whole “pipeline” into a programming one. You have a steady stream of data, and there are dedicated functions (let’s stick to functions now, simpler ones, and let’s not get to multithreading), that transform them, and output of one function is the input of others, until you get the satisfactory computation.

If these functions have limited processing power, and data just keeps coming in, why not have the data parked, and only process a handful at a time? So, welcome the data, but take only what your capable of. This phenomenon, this artificial buffer of data waiting to be processed- is back-pressure. If you think of it as a FIFO (First In First Out) queue, and the entrance is considered as “back”, then the pressure built up from incoming requests, would be back-pressure.

I am not so good with ELI5s and this was an attempt. Apologies if I failed at it.

mafinar

mafinar

Hello and welcome to DevTalk. I am not a moderator here but as someone who’s been active since this forum began, asking questions or opening posts is not considered a mess here but are welcome. And this is a place I interacted with some of the friendliest programmers I have met. So you are welcome to ask questions. Although ElixirForum is equally friendly.

AstonJ

AstonJ

This is a great idea @jaeyson!

We were going to start a ‘Glossary’ section on the Elixir Forum where a thread would be posted about something, and then people could explain it in their own words. If you’re a member you can see the thread here: https://elixirforum.com/t/do-you-think-we-need-a-glossary-section/12988

I think we could do such a version here (general dev), then another on the new Erlang Forums for BEAM related stuff - what does everyone think?

Great post btw Mafinar!

Where Next?

Popular General Dev topics Top

AstonJ
Thought it might be worth having a dedicated thread for standing desk treadmills (for those interested, here’s our general thread on stan...
New
New
AstonJ
It’s great to see how popular some of these channels have become - do you have any favourite YouTuber devs? Ben Awad Code...
New
finner
When you are under pressure to deliver you ideally want your Pull Request to be reviewed, approved and merged as quick as possible. So do...
New
New
Exadra37
I am a Linux user since 2012, more or less, and I always use Ubuntu on my computers, and my last 2 laptops have been used Thinkpads, wher...
New
New
foxtrottwist
A few weeks ago I started using Warp a terminal written in rust. Though in it’s current state of development there are a few caveats (tab...
New
jaeyson
Not trying to add more mess here but, reddit has ELI5 but i wanted to know if it’s okay to ask Elixir-specific (or outside of it) in a si...
New
malloryerik
With 100% less blockchain. I went searching for a lightweight immutable database that could be audited and ran into this. I guess this ...
New

Other popular topics Top

malloryerik
Any thoughts on Svelte? Svelte is a radical new approach to building user interfaces. Whereas traditional frameworks like React and Vue...
New
AstonJ
I’ve been hearing quite a lot of comments relating to the sound of a keyboard, with one of the most desirable of these called ‘thock’, he...
New
PragmaticBookshelf
Rust is an exciting new programming language combining the power of C with memory safety, fearless concurrency, and productivity boosters...
New
AstonJ
Just done a fresh install of macOS Big Sur and on installing Erlang I am getting: asdf install erlang 23.1.2 Configure failed. checking ...
New
AstonJ
Inspired by this post from @Carter, which languages, frameworks or other tech or tools do you think is killing it right now? :upside_down...
New
Exadra37
I am asking for any distro that only has the bare-bones to be able to get a shell in the server and then just install the packages as we ...
New
PragmaticBookshelf
“A Mystical Experience” Hero’s Journey with Paolo Perrotta @nusco Ever wonder how authoring books compares to writing articles?...
New
PragmaticBookshelf
Author Spotlight Mike Riley @mriley This month, we turn the spotlight on Mike Riley, author of Portable Python Projects. Mike’s book ...
New
PragmaticBookshelf
Author Spotlight: VM Brasseur @vmbrasseur We have a treat for you today! We turn the spotlight onto Open Source as we sit down with V...
New
AstonJ
This is a very quick guide, you just need to: Download LM Studio: https://lmstudio.ai/ Click on search Type DeepSeek, then select the o...
New