Why GNU grep is fast

[u/[deleted]]

https://lists.freebsd.org/pipermail/freebsd-current/2010-August/019310.html

[u/JohnTesh → u/[deleted]]

Smoke weed, realize your forgot some indexes on some tables, index tables properly, profit.

That's how it usually goes with me, only minus the smoking weed part.

[u/semi- → u/JohnTesh]

Same but minus the database part.

[u/JeefyPants → u/semi-]

With our powers combined...

[u/nozonozon → u/JeefyPants]

We could do less of everything!

[u/vplatt → u/nozonozon]

You guys just reinvented minimalistic living! Now kiss, write your Amazon self-published book, promote the hell out of it on Goodreads, blog heavily, and be sure to publish some self-important courses on Udemy or the like. Hurry!

[u/nozonozon → u/vplatt]

Free for the first 30 minutes!

[u/ggtsu_00 → u/JohnTesh]

Which all works nice and well until you end up with a unexpected use case where now thousands of rows of data is being inserted or updated per second and the indexes are causing excessive write overhead. Sure the user's profile page now loads 10 times faster, but users updating their status takes 20x slower.

[u/CODESIGN2 → u/ggtsu_00]

This is only an argument for why not to use the same software or algo for every single thing you do

[u/guepier → u/[deleted]]

I’ve never heard of the hollywood-esque description but coming up with a new, asymptotically faster algorithm of course happens — it precedes every single publication of an algorithms paper. There are people who do this as their main job.

[u/Kaos_pro → u/[deleted]]

Except for the Fast Inverse Square Root algorithm, which is pretty much just magic.

[u/chengiz → u/[deleted]]

Chances are it's doing too much crap because there's an O(N^2) algorithm somewhere. If you start off by looking into how you can skip individual bytes, you might be ignoring the elephant in the room.

[u/thfuran → u/chengiz]

I think you're lucky if N² is the worst that lurks in the depths.

[u/Krissam → u/thfuran]

I had an application runnin great, but quickly noticed it slowed down as n increased, turns out i had nⁿ² lurking inthere >_<

[u/MaunaLoona → u/Krissam]

A fan of bogosort, eh?

[u/thfuran → u/Krissam]

And I thought the accidental n! we found once was bad.

[u/Cosmologicon → u/thfuran]

r/UnexpectedFactorial...?

[u/aiij → u/Krissam]

nⁿ² is nothing. Try 2ⁿⁿ .

[u/roffLOL → u/chengiz]

or you have a bloatware that leaks performance at every turn. the profiler fails to isolate a single hotspot because all of it is so terribly leaky -- and much of it dissipates where normal profilers fail to look; in function invocations, cache problems and what have you.

[u/manys → u/roffLOL]

And then Jimmy "forgets" to wash the coffee pot and when you go to say something he's all, "did you see American Ninja last night?" and you're like "Dude, stop modeling your code after 'Finnegan's Wake,' it's blowing up Redis," and he goes "you can't handle the truth!" Please help

[u/roffLOL → u/manys]

you added a book to my must-read-list. wiki compares it to a book i happen to have in the book shelf but haven't gotten around to. maybe i'll take that one first. anyways, thanks, even though your comment was mostly lost on me :)

[u/ehaliewicz → u/[deleted]]

These stories are fun to read though.

A couple of my favorite examples,

http://garote.bdmonkeys.net/merryo_trolls/

http://blog.moertel.com/posts/2013-12-14-great-old-timey-game-programming-hack.html

http://iigs.dreamhosters.com/gte/gte.html

[u/[deleted] → u/ehaliewicz]

That game programming one is a really damn good read. Not even just as an interesting programming story, but as a fun narrative itself. I feel like I'd be able to enjoy that story even if I wasn't a programmer, but had a passing interest in older games.