this post was submitted on 13 Jun 2024
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Big brain tech dude got yet another clueless take over at HackerNews etc? Here's the place to vent. Orange site, VC foolishness, all welcome.

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[–] [email protected] -3 points 5 months ago (4 children)

UUIDs make great primary keys in some applications. If you generated 100 trillion UUID4s, there’s about a 1 in a billion chance of finding a duplicate. Thats usually good enough for my databases.

The issue here was that they used a single UUID instead of generating a new one for each record.

[–] [email protected] 19 points 5 months ago

There are countless issues here. They didn't do exception handling, they used a string to store their UUIDs (even if this was a DB constraint, you use sqlalchemy.Uuid and let the ORM and DB handle the translation), and as the person you're replying to stressed, they're using non-monotonic UUIDs. Also if you have a unique user_id and you're never exposing your primary keys, you don't need to get fancy, just let the ORM handle it with auto-incrementing, for most use cases. And so many other tragic things about this one tiny blog post.

tl;dr if you're going to copy code you don't understand, copy it from the docs, not from everything in the kitchen thrown into a blender.

[–] [email protected] 11 points 5 months ago* (last edited 5 months ago) (2 children)

they also stored this thing as a fucking string. looking up strings is costly.

[–] [email protected] 13 points 5 months ago (1 children)

naw bro we've got indexes bro it'll be fine bro

[–] [email protected] 10 points 5 months ago

can't wait for the Clever Idea to offload costly string indices to an external source composed of redis box and some shitfuck app doing tf-idf after a Extensive Research into how to make string lookups be faster

[–] [email protected] 10 points 5 months ago (1 children)

You’re missing the entire point of the post you replied to

[–] [email protected] 3 points 5 months ago (2 children)

I was reading it as an endorsement for autoincrementing int primary keys and a condemnation of uuids in general which is a genuine stance I’ve known people to take. Is that not it?

[–] [email protected] 8 points 5 months ago (1 children)

indeed, that is not it

hint: don't try to "read in" any extra meanings. just read the actual statement that was posted.

[–] [email protected] 7 points 5 months ago (1 children)

second hint: throw "monotonic UUIDs" into your search engine of choice

[–] [email protected] 1 points 5 months ago (1 children)

Would they not have monotonic uuids after altering the code in the article to use a function or lambda as they suggested?

[–] [email protected] 5 points 5 months ago* (last edited 5 months ago) (2 children)

~~you might know what "monotonic" means if you had googled it, which would also give you the answer to your question~~

edit: this was far too harsh of a reply in retrospect, apologies. the question is answered below, but i'll echo it: a "monotonic UUID" is one that numerically increases as new UUIDs are generated. this has an advantage when writing new UUIDs to indexed database columns, since most database index structures are more efficient when inserting at the end than at a random point (non-monotonic UUID's).

[–] [email protected] 1 points 5 months ago (2 children)

I’ve more of a math background than cs so monotonic is a word I know well but it apparently means something slightly different to me. Monotonicity isn’t mentioned anywhere in that link.

[–] [email protected] 7 points 5 months ago (2 children)

okay, for some reason, I feel the need to help.

The given link defines the function that creates a UUID:

uuid.uuid4(): Generate a random UUID.

In mathematics, can you generate a monotonic function by generating random numbers?

[–] [email protected] 6 points 5 months ago

Thanks for trying to explain it. I was hung up on thinking all UUIDs looked like UUID v4. I read up a little on UUID v7 and it’s making sense. Probably should’ve done that sooner.

[–] [email protected] 5 points 5 months ago

you are probably a better person than i am for actually giving an explanation

[–] [email protected] 6 points 5 months ago

just stop digging, sheesh

[–] [email protected] 0 points 5 months ago* (last edited 5 months ago) (3 children)

Everything after this is so pointlessly condescending and confusing. Even if someone knows what monotonic ids are it doesn't automatically mean they're going to have any clue about what that means with regards to index performance. In the spirit of not being an asshole, I'll write it out here based on my research since everyone else just seems interested in putting others down rather than being helpful.

  • "Monotonic" implies something that is always increasing (or decreasing). You'll never get a result that's lower than one you've gotten before (or higher if you're dealing with monotonically decreasing stuff).
  • Random UUIDs are not monotonic because they're random.
  • Even time based UUIDs are not monotonic because of the format. Rather than being store high, medium, low, they're stored low, medium, high. Think of it like storing numbers like "1 20 300" for 321. 322 would be "2 20 300". To make it worse, the end of them is "random" (a MAC address). So, not monotonic at all because MAC addresses can change. (See here for proposed new formats, where they mention this as a problem https://www.ietf.org/archive/id/draft-peabody-dispatch-new-uuid-format-04.html)
  • Monotonic primary keys are useful because they're more easily inserted into an index because you're always inserting into one specific part of the index rather.
[–] [email protected] 10 points 5 months ago* (last edited 5 months ago)

putting my 2¢ forward: this is a forum for making fun of overconfident techbros. i work in tech, and it is maddening to watch a massively overvalued industry buy into yet another hype bubble, kept inflated by seemingly endless amounts of money from investors and VCs. and as a result it's rather cathartic to watch (and sneer at) said industry's golden goose shit itself to death over and over again due to entirely foreseeable consequences of the technology they're blindly putting billions of dollars into. this isn't r/programming, this is Mystery Science Theater 3000.

i do not care if someone does or does not understand the nuances of database administration, schema design, indexing and performance, and different candidates for the types of primary keys. hell, i barely know just enough SQL to shoot myself in the foot, which is why i don't try to write my own databases, in the hypothetical situation where i try to engineer a startup that "extracts web data at scale with multimodal codegen", whatever that means.

if someone doesn't understand, and they come in expressing confusion or asking for clarification? that's perfectly fine -- hell, if anything, i'd welcome bringing people up to speed so they can join in the laughter.

but do not come in here clueless and confidently (in)correct the people doing the sneering and expect to walk away without a couple rotten tomatoes chucked at you. if you want to do that, reddit and hacker news are thataway.

[–] [email protected] 7 points 5 months ago (2 children)

Yeah, I'm all for dunking on promplets, but just being wrong about best practice isn't a big deal. The reaction here is excessively harsh.

[–] [email protected] 10 points 5 months ago (1 children)

agreed. we’ve veered a bit too close to slashdot’s tone on this one.

with that said, I’m also acutely aware of the tactics that programming.dev reply guys use to generate these kinds of responses. to our guests: it’s best to take your questions about database best practices literally anywhere else but here.

[–] [email protected] 6 points 5 months ago

with that said, I’m also acutely aware of the tactics that programming.dev reply guys

I wasn't actually aware of this, and will be taking note of it in future. for my part I tried to make my reply "uhh go look at $x and learn" post without, y'know, overtly making things into a not-meant-for-here debate setup, but that didn't seem to have worked out entirely well :)

[–] [email protected] 9 points 5 months ago (1 children)

Just to be clear, if a person is wrong about best practices then it's not a big deal.

In context of spicy autocomplete as coding assistance, it better output immaculate, robust code every fucking time or we should be clowning on it with zero remorse.

[–] [email protected] 6 points 5 months ago

Wait a second...to err is to be human. Programmers err sometimes. ChatGPT shits itself all the time...😟. Yud et al. were right

[–] [email protected] 6 points 5 months ago (1 children)

Read the sidebar. This is literally not the place.

[–] [email protected] -5 points 5 months ago (2 children)

The fuck is a side bar? My app doesn't have that. Be more specific, please.

[–] [email protected] 11 points 5 months ago

If your "app" cannot show basic information about the forum to which you are posting, your "app" is bad.

[–] [email protected] 10 points 5 months ago

no, programming.dev, let’s fucking not

[–] [email protected] -1 points 5 months ago* (last edited 5 months ago) (1 children)

They're good for large, distributed applications for sure. Better than incrementing integers for those kinds of applications at the very least.

For the folks in the article though? lol they were making no good decisions

[–] [email protected] 14 points 5 months ago* (last edited 5 months ago) (1 children)

when you do not yet have (1) customers, (B) unit tests, (ג) developers who can write their own code, or (IV) exception handling, the term-of-art that comes to mind for doing anything besides auto-incrementing primary keys is YAGNI. (Especially because nobody who is making thoughtful, careful database tuning decisions is using chat-gippity to convert their models. And more to the point, they aren't using SQLAlchemy of all things to make large, distributed applications that need UUID primary keys.)

[–] [email protected] 0 points 5 months ago* (last edited 5 months ago) (1 children)

Oh for sure, the article folks are inept and absolutely not the people I was talking about. I'm just talking about stuff more like Discord or Steam that are huge distributed systems that don't use centralized databases.

Edit: that don't use centralized databases. I blame the ADHD.

Edit 2: I am agreeing with this person

[–] [email protected] 9 points 5 months ago (2 children)

I'm just talking about stuff more like Discord or Steam that are huge distributed systems that don't use databases.

huh???

[–] [email protected] 8 points 5 months ago (1 children)

Whoops, I flubbed that message hard and didn't catch it at the time: Meant to say "don't use centralized databases." They definitely use databases lmao. No idea how I screwed that message up so hard. I blame ADHD for not proofreading.

Just so we're on the same page, let me be more specific. I'm saying the individuals in the article were making terrible decisions. Lots of them.

I am also saying that UUIDs are good primary keys for very specific purposes: Large, distributed systems that handle large amounts of small data, powered by databases like Cassandra that are designed to handle millions of record insertions per hour across several hundred nodes, to the point where inserts are very likely to happen at the exact same time on two different replicas of the same schema.

Hope that makes more sense than my previous flub. lol

[–] [email protected] 5 points 5 months ago* (last edited 5 months ago)

okay that's a little more sensible lol

i think the original comment that this thread is in reply to is avoiding non-monotonic UUIDs. i don't think anyone is contesting that autoincrementing ints create headaches when trying to distribute the database

[–] [email protected] 5 points 5 months ago (2 children)

See, reason being is they use aethernet - that’s the only way you get to get scale it like this. Without that, communication and storage would just be impossible!

[–] [email protected] 8 points 5 months ago (1 children)

I accidentally a word in the original comment, it was supposed to say they don't use *centralized databases. Instead it said I'm a moron lmao.

[–] [email protected] 5 points 5 months ago

Bit of a whoopsie, that :)

[–] [email protected] 6 points 5 months ago

And I just saw what that poster’s domain is, fuck me