My £4 a month server can handle 4.2M requests a day • Hacker News Board

Re: My £4 a month server can handle 4.2M requests a day

#251

Post by sillycube » Wed, Sep 08, 2021, 3:40 AM UTC

napworth wrote: post #88

polote wrote: post #41

What's the point of this post? OP is serving a file at 50req/sec. There is not even mention of a dB query. How is that able to relate to any kind of normal app? I guess that the post was written as an answer to the mangadex post [1]. Mangadex was handling 3k req/sec involving dB queries. It was not just a cached Html page. 50req/sec for a Html file is super low which shows that a $4 month server cant do much actually…

It's called boasting

Boasting of what? Serving static sites doesn't even need a server.

Use apache to serve Django + wsgi? Just use Django asgi and nginx and you will get a higher number.

Re: My £4 a month server can handle 4.2M requests a day

#252

Post by rapsey » Wed, Sep 08, 2021, 3:42 AM UTC

FridgeSeal wrote: post #184

xfitm3 wrote: post #138

Earlier quoted context omitted.

In my experience disk i/o is the biggest bottleneck. It used to be sync()ing writes to disk for strict consistency but that's been pushed down to the DB now. I just looked at my DB systems and CPU is low but disk is nearly pegged. My data sets are far too big to fit into memory/cache. Disk pressure can be alleviated by optimizing queries but it's a game of whack-a-mole. I have exhausted EBS i/o and been forced to res…

Does anyone know if any of the current crop of standard databases make use of things like Direct IO (where available on Linux), I’ve seen some write-ups that indicate you can get eye-wateringly fast performance when combined with an nvme drive.

Scylla is built arround direct io.

Re: My £4 a month server can handle 4.2M requests a day

#253

Post by spfzero » Wed, Sep 08, 2021, 3:45 AM UTC

nostrademons wrote: post #196

Waterluvian wrote: post #191

Earlier quoted context omitted.

What reminded me of this the other day is how MacOS will grow your cursor if you “shake” it to help you find it on a big screen. I was thinking about how they must have a routine that’s constantly taking mouse input, buffering history, and running some algorithm to determine when user input is a mouse “shake”. And how many features like this add up to eat up a nontrivial amount of resources.

That particular example seems like something that's probably a lot cheaper than you'd initially think. The OS has to constantly take mouse input anyway to move the pointer and dispatch events to userspace. It also needs to record the current and new position of the mouse pointer to dispatch the events. Detecting whether the mouse is being "shaken" can be done with a ring buffer of mouse velocities over the last secon…

That's some actual engineering there, understanding the problem you're trying to solve, instead of solving problems you don't even have. Nice.

Re: My £4 a month server can handle 4.2M requests a day

#254

Post by seandong » Wed, Sep 08, 2021, 3:47 AM UTC

All these examples show even more why software engineer(not developer) is a discipline where 10x salary difference can be seen between the best and the worst. For the 10x you are paying, you are getting a (n^2 - logN) times performance gain, especially when you are dealing with problems with large amount of data.

However, relying on people themselves is often not the best stable solution. I am wondering if all these N^2 mistakes people made can be prevented by innovative means like language features, framework improvements, tooling and etc. And I'm talking about prevention, not the post mortem perf measure and fix kind

Re: My £4 a month server can handle 4.2M requests a day

#255

Post by spfzero » Wed, Sep 08, 2021, 3:51 AM UTC

JJMcJ wrote: post #129

danudey wrote: post #90

Earlier quoted context omitted.

A lot of that is due to absolutely lousy code. We had a system management backend at my last company. Loading the users list was unbearably slow; 10+ seconds on a warm cache. Not too terrible, except that most user management tasks required a page reload, so it was just wildly infuriating. Eventually I took a look at the code for the page, which queried LDAP for user data and the database for permissions data. It did…

Your pattern is quite powerful: get data from several sources and do the rearranging on the client (which might be a web server), instead of multiple interactions for each data item. For SQL you can also do a stored procedure. Sometimes that works well if you are good at your DBMS's procedure language and the schema is good.

Though stored procs will always execute on the server that is probably already the system bottleneck.

Re: My £4 a month server can handle 4.2M requests a day

#256

Post by doublepg23 » Wed, Sep 08, 2021, 4:01 AM UTC

hypertele-Xii wrote: post #237

trisiak wrote: post #234

Earlier quoted context omitted.

What's behind the mouse cursor while you're doing it? Could it be the UX/UI layer keeping state up-to-date? Other possibility, do you have a gaming mouse with 1000Hz polling rate configured?

Yeah, it's a high quality mouse. But the only excuse for this is it's slightly cheaper to make everything USB. PS/2 worked much better. It was limited to 200Hz but needed no polling. Motherboards just stopped providing the port.

Gaming or off the shelf prosumer mobos still have PS/2 on them occasionally. Although, it's probably just using a converter to USB anyway.

Re: My £4 a month server can handle 4.2M requests a day

#257

Post by [deleted] » Wed, Sep 08, 2021, 4:03 AM UTC

wyager wrote: post #224

pdimitar wrote: post #194

Earlier quoted context omitted.

I'm curious if you evaluated Rust?

At that point there were not any tried and true Rust web frameworks, although a priori I would expect any Rust web offerings to be pretty solid.

[deleted]

Re: My £4 a month server can handle 4.2M requests a day

#258

Post by jfrunyon » Wed, Sep 08, 2021, 4:05 AM UTC

diath wrote: post #179

jfrunyon wrote: post #84

Earlier quoted context omitted.

I would guess they may be muxed over fewer sockets, by their LBs, but that's not strictly necessary. I'm not sure exactly what you mean by "run out of TCP sockets", but theoretically speaking, the only limitation is how much memory is available to store the necessary info about the socket (like address/protocol info and process info). In practice, OS's do have a "max socket" or "max FD" limit, but that's usually conf…

> I'm not sure exactly what you mean by "run out of TCP sockets", but theoretically speaking, the only limitation is how much memory is available to store the necessary info about the socket (like address/protocol info and process info). Probably the 65k port limit since each connection will get assigned a remote port, which can be solved by binding to multiple local ports and using a load balancer in front or using…

The 65k limit is per client address and port. Each client can have 65,535 connections to a single port on your server from each and every 65,535 of their own ports. (65,536? I dunno what would actually happen if you tried to use port 0.)

Re: My £4 a month server can handle 4.2M requests a day

#259

Post by erdo » Wed, Sep 08, 2021, 4:14 AM UTC

Working on other companies' mobile apps, about half the performance problems I've discovered have been down to some accidental crazy, like initialising something you only need once, in a loop, in 3 different places (because the code has become so unnecessarily complicated that no one really knows what it's doing). The rest are due to some piece of code accidentally blocking the UI thread.

A well written mobile app doesn't really have any need to be sluggish at all, including smooth animations and fast scrolling lists, it was doable 10 years ago, it's doable now. (*I don't know about games).

But unlike on the server side, the accepted wisdom in most places I've worked at is that the answer to the performance problems is: a new framework.

(I feel like this is a lie that developers tell the business side, and maybe themselves. It avoids having to explain that software is hard, sometimes you don't get it right the first time, and if you don't spend time and effort tending to it, it can turn into an ungodly and expensive mess - and that's got nothing to do with the hardware or the framework)

Re: My £4 a month server can handle 4.2M requests a day

#260

Post by lilyball » Wed, Sep 08, 2021, 4:22 AM UTC

Const-me wrote: post #199

Waterluvian wrote: post #191

Earlier quoted context omitted.

What reminded me of this the other day is how MacOS will grow your cursor if you “shake” it to help you find it on a big screen. I was thinking about how they must have a routine that’s constantly taking mouse input, buffering history, and running some algorithm to determine when user input is a mouse “shake”. And how many features like this add up to eat up a nontrivial amount of resources.

> they must have a routine that’s constantly taking mouse input Possible but unlikely. Well-written desktop software never constantly taking input, it's sleeping on OS kernel primitives like poll/epoll/IOCP/etc waiting for these inputs. Operating systems don't generate mouse events at 1kHz unless you actually move the mouse.

“Constantly taking” is not the same thing as “constantly polling”. The ring buffer approach works identically in the event-driven approach, you just need to calculate the number of “skipped” ticks and zero them out in the ring buffer.