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Why and How I Switched from Python to Erlang
- coltonv 10y agoIf you're going to set pixel based margins on the left and right side of your page, you need a media query to disable it or at least lower it to 5 pixels on small screens. This is unreadable on mobile :/
- stephengillie 10y agoWith JavaScript disabled, it's just a long bar of text about 18 letters wide.
- bhalp1 10y agoIf you're on iPhone you can use the reader button. Android may have something similar. Obviously I agree with the advice though.
- zzleeper 10y agoI'm always surprised why more people don't just do F12, ctrl+shift+M (on Chrome) while writing their websites. Just four keystrokes :)
- rodmena 10y agoFixed.
- abrookewood 10y agoAwesome! Had no idea you could do this! For those wondering, it renders a mobile-like view of the current site. Thanks ;)
- jboogie77 10y agodidn't really explain how.... لطفا بیشترتو ضيح بدید
- daveguy 10y agoلطفا بیشترتو ضيح بدید ? I tried Google for translation. It wasn't very helpful. Edit: ok, close enough -- "Please explain me Byshtrtv" Edit2: replier and op were much more helpful than google, thank you!
- rodmena 10y agoIn Persian. He means: "Explain More"
- jboogie77 10y agodon't forget please :)
- daveguy 10y agoWish I could answer and say you're welcome, but I agree with you. It seems to be some dubious why and no how. Dubious in that he gave an arbitrary and unsubstantiated 500ms benchmark for Python.
- rodmena 10y agoI updated and clarified it. 500ms is a web2.0 rule. You should give users a status about long process requests. Thats it.
- rodmena 10y agoWell, It was version 1! I will try to explain more and more in coming days. I wrote these articles for mind rest and between my coding sessions.
- daveguy 10y agoLooking forward to the follow up!
- flocial 10y agoToo bad the author doesn't show specific examples. I can sympathize with the sentiment. The problem with scaling languages like python and ruby in my experience is the number of moving parts and jump in deep knowledge required to scale when your application takes off. One day you're happily writing compact code in your favorite language and suddenly you're rewriting core parts in C/Go/Rust while learning a new language and bolting on a variety of moving parts like redis, memcached, etc. to keep your business from becoming a victim of its own success. A lot of the problems are more or less solved problems with well known workarounds but it's still a pain and probably why there's so much buzz around finding the "next (insert your favorite language/framework)". Erlang generated a lot of buzz several years ago but aside from the recent success of WhatsApp it never quite stuck. I'm curious to know how this author thinks differently.
- themartorana 10y agoNow is a fantastic time for languages. Python and Ruby get you where you need to be fast, and if you get far enough and need to scale, there are a huge number of options, from stalwart holdouts like Java and C# (now on Linux!) to newer languages on rock-solid run times like Clojure and Elixir, to whole new languages like Go and Rust. All these languages have their advantages and followers, but the thing they all have in common is first-class concurrency, which everyone now realizes they need (and old Erlang devs will tell you "duh"). Honestly, while I write Go almost exclusively anymore, I think Elixr is the most exciting. The more I learn about Beam the more magical it becomes in my eyes, considering just how old and stable it is. Phoenix is a game changer in many ways.
- rodmena 10y agoElixir Introduces many new concepts to Erlang. I think it adds to the complexity of language. Erlang is enable to do all with a bit more functional code. Overall I agree that Erlang based frameworks are game changer.
- flocial 10y ago> I think it adds to the complexity of language. How so? What makes Erlang more functional? And how is Erlang simpler for you? A big part of the renaissance in programming languages come from developers leveraging rock solid VMs such as BEAM and JVM. It enables developers to have the expressiveness of dynamic languages and without sacrificing performance or scalability later down the road. In the case of Elixir, many feel that it adds some innovative language features like the pipe ("|>") operator and metaprogramming facilities that ease many of the pain points with Erlang. I'm not an expert in Erlang but there are quite a few notable Erlang developers that enthusiastically support Elixir (including some nice words from Joe Armstrong). I'm not arguing with you but curious about your thoughts. Looking forward to the next installments in your series.
- kccqzy 10y agoAn SQL injection issue right there. Edit: to be fair the variable proj_id sounds like it's not taken from untrusted input, but nevertheless a bad idea.
- rdtsc 10y agoI use both Python and Erlang. Python is to get small stuff done quickly language for me. And "small" doesn't have to be just a demo or hello_world example, it can be a whole full back-end of a business. (And btw when I say Erlang I also mean Elixir, they both share the same VM so most things apply to both). But Erlang is a the secret sauce (so to speak) for a high concurrency fault tolerant backend. "Fault tolerant" should probably go first. The reason is the observation that the higher the concurrency or complexity in the system, the higher the need for fault tolerance. If you only serve 10 connections and the backend segfaults, 10 clients have lost connectivity, you get 10 angry phone calls. If you serve 1M connections and your backend segfaults, you get 1M phone calls. Exaggerating here of course to get the idea across. But this is not just a marketing gimmick, this translates to money in the pocket in operational costs. Some subsystem crashes and restarts? Fine, let it do that if it is 4am, no need to wake people up, will fix in the morning. I've heard of stories of subsystems crashing and restarting for years with the main service staying up. The lack of centralized state might seem minor but unless you have been debugging a shared memory systems with locks, threads and manual memory allocations, with classes that have pages of attributes defined, and trying to understand why it crashes on Wednesdays only at customer A's site, it is easy to miss the benefit. This comes through using small lightweight processes with an isolated heap and also using functional constructs. Then in general, the ability to reason about concurrency using OTP constructs (Erlang's standard library) and processes is like going from Assembly to C in terms of distributed and concurrent systems. Can express ideas at a higher level. This means having less code to look through and maintain. There are other niceties like good garbage collection performance, awesome tracing and hot code loading capability (used this a few times, so started to appreciate it more now). Now, individually all of those features can probably be found in other systems and frameworks, but they are just not integrated or not quite there -- Java has code loading but it is not the same. Can always spawn an OS process to get fault tolerance, but can only spawn so many before system falls down, Go has goroutines but they also share memory, so fault tolerance is not there. Other languages have garbage collection, but most still have to stop the world sometimes and so on.
- emluque 10y agoYou seem to be familiar with Elixir. May I ask you some questions? . What kind of web applications are you building with it? I'm asking what kind of web apps or scenarios do you think Elixir is particularly well suited for? I saw a thread on Elixir a couple of days ago and it piqued my interest and I saw a couple of videos that were posted there, one from some Ruby Conf that claimed that Elixir was giving better results (in request time) than rails. He never explained how that was posible or what would have been the results if he would have been using a cache (it's always faster to hit an in memory cache than hitting a db that has to touch disks, so if he speeded things up without a cache he would speed things even more with a cache). Then I watched another videos from some conference in Oslo or something, and from what I could understand he was doing away with the db completely. . So I have another question, how do you architect your application in Elixir to keep application state though multiple requests (sessions) on multiple boxes without using something like memcached or redis (or a network disk)? . Even if it's running on only one Box? Where does data reside if you are not using a db? I have a basic understanding of Erlang processes (what's explained here: http://stackoverflow.com/questions/2708033/technically-why-are-processes-in-erlang-more-efficient-than-os-threads http://stackoverflow.com/questions/2708033/technically-why-a...) and how it's particularly well suited for concurrency. My questions are about Web Apps and Elixir and scaling.
- smcl 10y agoI'd be curious as to why exactly the SQLAlchemy query was slower than the raw one. I get that there's gonna be some overhead, but did you figure out exactly what was slowing it down?
- Qantourisc 10y agoI have been comparing the 2, at third glance they don't even appear the be the same query. Second for performance as much as possible from the SQL building should be outside the function. Also if the query is that static, you should probably use the plain SQL anyway ;) Or maybe even build the SQL query string by using SQL alchemy outside the function, and then using the SQL generated by SQLAlchemy inside the function (if you don't like pure SQL, like for example compatibility).
- ben_jones 10y agoThe title should be: Mentioning some scaling problems I heard about in Python and might have brushed up against in my own projects (likely not production ones). Oh and their's this thing call Erlang and it's fast! I sincerely hope nobody is making changes to a working production stack based on posts like this.
- ngrilly 10y agoTwo comments: - It looks like the SQL queries produced by pure_python() and simple_sql() are structurally different, which would make any comparison worthless. - How does the author solve the long running tasks (> 500 ms in the article) problem with Erlang? In Python, it looks like he was using Celery with Redis then RabbitMQ. What does he use in Erlang? (Erlang message queues have no built-in persistence.)
- ken47 10y agoCan't comment on what the author used, but Mnesia can be used to build a primitive, durable MQ: http://learnyousomeerlang.com/mnesia http://learnyousomeerlang.com/mnesia There is also RabbitMQ, which itself is written in Erlang.
- dozzie 10y agoWell, Mnesia could be used to build that, but what for in the first place? You just spawn a worker process under a supervisor and leave it to finish its job. Really, no need for a queue (unless you want to postpone some tasks until some others finish, but this is more synchronization problem and can be solved without fully-blown database).
- loxs 10y agoErlang can have long living processes (green threads) and that's usually how we solve problems. There is absolutely no problem (it's encouraged) to have thousand of processes living minutes or hours if we need so.
- ngrilly 10y agoYes, but how do you manage fault tolerance at the machine level? If the machine is rebooted for some reason, the pending messages will be lost, and will never be processed. A persistent queue is necessary for this reason. This is the reason why people use tools like Celery or RabbitMQ (which is written in Erlang by the way). I don't see how replacing Python with Erlang changes anything in this regard.
- mianos 10y agoYou might notice difference in performance when your sqlalchemy query is different to your raw query. If you don't understand sqlalchemy then you are probably best to not use it. How about going to mongo?
- erikb 10y agoYes, for certain programming jobs (i.e. work) Erlang is much better. Let's just assume we can mostly agree on that. But "I switched" means you switched your main language, right? I wouldn't switch my main tool to something with a specific usecase. Your main language should be something general purpose, because most of your life's problems have a wide range of usecases to consider. Therefore I would have expected an argument for why Erlang may be a beter general purpose language or a headline like "Why <project/company/service x> switched from Python to Erlang".
- abrookewood 10y agoYes, the article was pretty badly written I thought. It was mainly just complaints about Python than any real exploration of why Erlang was better.