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StackOverflow Update: 560M Pageviews a Month, 25 Servers

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Re: StackOverflow Update: 560M Pageviews a Month, 25 Servers

#251

Post by BrandonM »

jacques_chester wrote: post #225
noelwelsh wrote: post #207

StackOverflow shows just how powerful using a fast language can be. Compare the TechEmpower benchmarks for, say, Java vs Rails on a very simple JSON serialization benchmark (we can assume .Net would achieve comparable performance to the JVM): http://www.techempower.com/benchmarks/ The Java servers get around 900K requests/s on beefy hardware while Rails squeezes out 6K. That's a 150x difference! Any real application…

> It's a one off cost to learn an efficient language, but it pays returns forever. It also imposes costs forever. Software is never finished.

Java 8 + an IDE like NetBeans (which isn't even the best Java IDE) is actually a very pleasant development experience. I am a total convert from Python in vim to Java in NetBeans+jvi.

Refactoring in Python or Ruby or Javascript or whatever dynamic language is extremely painful compared to doing it in a static one. The "Software is never finished," argument can also work against dynamic languages.

Re: StackOverflow Update: 560M Pageviews a Month, 25 Servers

#252

Post by tjdetwiler »

BrandonM wrote: post #251
jacques_chester wrote: post #225

Earlier quoted context omitted.

> It's a one off cost to learn an efficient language, but it pays returns forever. It also imposes costs forever. Software is never finished.

Java 8 + an IDE like NetBeans (which isn't even the best Java IDE) is actually a very pleasant development experience. I am a total convert from Python in vim to Java in NetBeans+jvi. Refactoring in Python or Ruby or Javascript or whatever dynamic language is extremely painful compared to doing it in a static one. The "Software is never finished," argument can also work against dynamic languages.

Have you tried IntelliJ?

Re: StackOverflow Update: 560M Pageviews a Month, 25 Servers

#253

Post by ProAm »

icebraining wrote: post #250
ProAm wrote: post #247

Earlier quoted context omitted.

But you still have to go to a different site to have any hope of getting the chance to ask your question. It'd be like going to Home Depot and needing information that is related to building supplies but the employees tell you you must go to a different store down the street to even ask your question.

On Reddit you have to post separately on different subreddits, there's no way to simply "post to Reddit" either. I don't agree with your analogy; I think it's more akin to going to Home Depot to ask for vegetables. I think it makes perfect sense to have a separation between Cooking.SE, Photography.SE, Christianity.SE, etc. There are a few edge cases, primarily in the tech sites, but I don't think those disprove the m…

Yeah Im speaking primarily about the technical SE's sites. I agree with the completely isolated SE (Photography, Puzzles, religion).

But when you get the related topics servers, programming, security, tools, web development, web apps... All these items are so closely related it's often disadvantageous to try and ask a vertically silo'd question.

I get they are trying to create a detail 'manual' for all questions, but you get to a point where it's just better to read the manual.

Re: StackOverflow Update: 560M Pageviews a Month, 25 Servers

#254

Post by swah »

nostrademons wrote: post #125
edgyswingset wrote: post #26

Earlier quoted context omitted.

Rigid adherence to certain technologies could be a culprit. "We're a Ruby shop!" is fine for problems where Ruby is great, but the limitations of the technology are bound to creep up somewhere. Not using a polyglot approach would be bad.

It can also be caused by too much embrace of polyglot tools. "We use the best tools for the job" can easily mean an architecture with Redis, Memcached, Mongo, MySQL, Angular, JQuery, Node, and several dozen third-party libraries, all glued together with Thrift or JSON-RPC. If all you're doing is a messaging app, you might be much better off with a single in-process Java app. Usually you want your solution to be just…

I wish more people considered this alternative when recommending the usage of queues etc. I always remember of this post: http://williamedwardscoder.tumblr.com/post/18065079081/cogs-...

Re: StackOverflow Update: 560M Pageviews a Month, 25 Servers

#255

Post by hudo »

Maarten88 wrote: post #242
noelwelsh wrote: post #207

StackOverflow shows just how powerful using a fast language can be. Compare the TechEmpower benchmarks for, say, Java vs Rails on a very simple JSON serialization benchmark (we can assume .Net would achieve comparable performance to the JVM): http://www.techempower.com/benchmarks/ The Java servers get around 900K requests/s on beefy hardware while Rails squeezes out 6K. That's a 150x difference! Any real application…

> StackOverflow shows just how powerful using a fast language can be. Compare the TechEmpower benchmarks [...] (we can assume .Net would achieve comparable performance to the JVM) Except those TechEmpower benchmarks show .NET is not nearly as fast as Java. I think StackExchange prove that the platform is NOT the most important: it's much more important to make performance a priority in all engineering decisions, to b…

Those test there are much more web server + platform tests, and can be hardly taken as java vs .net vs something

Re: StackOverflow Update: 560M Pageviews a Month, 25 Servers

#256

Post by cruise02 »

bikamonki wrote: post #151

I never ever ever never use SO's search feature: I land on the result through Google. So I guess they should give Google some credit for the claimed performance?

Google isn't serving Stack Exchange's pages to you. They published stats on pages served by their own servers. Google has nothing to do with it.

Re: StackOverflow Update: 560M Pageviews a Month, 25 Servers

#257

Post by edwinnathaniel »

bjourne wrote: post #141
numbsafari wrote: post #119

Earlier quoted context omitted.

My guess is that they feel that the layers of indirection and abstraction often needed to make TDD work result in an object creation pattern that results in heavy GC load during normal operation. The references to "using static methods" is probably related to this. ps. That's my guess, but I'd encourage you to post your question to the meta site for SO.

IME that always happens when you try to perform tdd in combination with Javaesque encapsulation. The good solution to the problem is to not be so afraid of classes seeing each others internals. The bad solution is to add, factory patterns, dependency injectors and other useless layers just to try and keep your design both well encapsulated and testable.

You do realize that most efficient DI framework only inject the dependency once.

Separating Controller, Repository, and Services are good practices as well and let's be honest, we're looking at 3 methods layer at most.

Here's what happened in Java:

1. When you deploy your WAR, the DI will inject necessary component _once_ (and these components only instantiated _once_ for the whole web-app so there you go, Singleton without hardcoding).

2. A request comes in, gets processed by the pumped-up Servlet (already DI-ed). If the servlet has not been instantiated, it will be instantiated _once_ and the instance of the Servlet is kept in memory.

3. Another request comes in, gets processed by the same pumped-up Servlet that is already instantiated and has already been injected with the component (no more injection, no more instantiation, no more Object to create...)

So I've got to ask this question: what GC problem we're trying to solve here?

Some of the static methods are understandable but if Component A requires Component B and both of them have already been instantiated _once_ and have been properly wired up together, we have 2 Objects for the lifetime of the application.

I'd pay for a wee bit extra hardware for the cost of maintainable code ;)

Discipline (and knowledge of object graph) definitely help to reach to that point.

Re: StackOverflow Update: 560M Pageviews a Month, 25 Servers

#258

Post by tannerj »

hudo wrote: post #127
UVB-76 wrote: post #18

Anyone else not quite expecting StackExchange to be using a Microsoft stack?

Jeff Atwood hacked prototype and next several versions, and since he's a .net guy (and ruby guy now), that's why .net was picked. Lot about tech stack planning can be heard in first few SO podcasts, don't even know if there're still available online somewhere

I haven't listened to these yet, but I think this is what you are referring to:

http://blog.stackoverflow.com/2008/04/podcast-1/

Re: StackOverflow Update: 560M Pageviews a Month, 25 Servers

#259

Post by GeorgeBeech »

Scuttles wrote: post #248
Nick-Craver wrote: post #179

Earlier quoted context omitted.

> One must wonder, how much better this setup would of scaled had it been a more appropriate webserver stack such as Linux/BSD + Apache/Nginx or similar I guess you're gonna have to define "more appropriate" for me, I have a feeling we'll have a fundamental disagreement there. We could (and have) run the entirety of our peak load with 1 SQL server and 2 web servers (and not pegging them). Don't forget we run with a c…

Where I come from, it is considered bad engineering to build a product that can only run on a single platform, can only run on one particular OS, and the product is at the mercy of future decisions by a 3rd party. We go out of our way to ensure we are not dependent on any single thing. Even if it was the best choice at the time to go the Microsoft route, it may not be in the future... however -- SE has zero choice no…

>Where I come from, it is considered bad engineering to build a product that can only run on a single platform, can only run on one particular OS, and the product is at the mercy of future decisions by a 3rd party.

This seems like a bit of a waste of resources to try and run an internal bespoke application on every platform imaginable. Now, if you are developing a product that you are then going to sell to other people to run on their own hardware this make more sense.

There are some very big benefits to writing to a specific platform, especially in the performance space.

In the end of the day it is a trade off between trying to eliminate every 3rd party dependency (next to impossible) or picking a solution or company you think will be around for a long time, and forging strong relationships with them.

We regularly talk to people at Microsoft (and all of the people who create and build to tools we use), give them feedback, and get bugs fixed. There is very little that comes down the pipe from them that we are not away of ahead of time and in some cases have helped shape through early access programs.

> SE has zero choice now otherwise they'd have to re-write their entire product...

This is not true at all, we have choices if MS decided to blow everything up. Not great choices, but we have them. Choosing between two or three crap options does not mean that options do not exist.

-George (SE Sysadmin)

Re: StackOverflow Update: 560M Pageviews a Month, 25 Servers

#260

Post by thomasz »

Nick-Craver wrote: post #236
thomasz wrote: post #233

Earlier quoted context omitted.

The usual wisdom in clr-land is that the generational garbage collector can cope just fine with a lot of small, short lived objects. It absolutely doesn't like big, long lived objects that reach G1, G2 or the large object heap and must be traversed for a full gc. This means that normally, you want to avoid data structures that introduce a lot of objects trees, linked lists and stuff like that. In some circumstances y…

It depends on your definitions of "a lot" is. It can scale pretty high by default, but when you're doing hundreds of millions of objects in a short window, you can actually measure pauses in the app domain while GC runs. These have a pretty decent impact on requests that hit up against that block. The vast majority of programmers need not worry about this, but if you're putting millions of objects through a single ap…

Are you sure that this is really because of Gen0 collections all by themselves, and not because the short cadence of collections leads to a lot of premature Gen1 promotions? I could imagine something like

   var a = InitGiantArray();
   var b = InitGiantArray();
could leave you with a lot of foo garbage in Gen1 or even Gen2, right were it really hurts. On the other hand I'd be surprised if something akin to

   do {
       Tuple.Create(new object(), new object());
   } while (true);
but with something useful thrown in would suffer much under GC pauses. Looks like I have to test it :I)
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