Siege, a DBMS written in Haskell

http://www.haskell.org/pipermail/haskell-cafe/2011-December/097907.html

by DanWaterworth • 15 years ago

98 20 15 years ago

tikhonj4• 15 years ago

It's always cool to see a nontrivial Haskell project.

This is also a great answer to one of the more prevalent complaints I hear about Haskell, namely that it is only good at the things it was designed for. I think it's safe to say that writing a database was not one of the things it was "designed for"; I'm also assuming you were relatively happy with the language for this project.

One niggle: have you considered reorganizing your directory structure to look vaguely like this[1]? This should make packaging your project and adding tests easier. Using hierarchical modules (e.g. Database.Seige.DBList instead of just DBList) is probably also a good idea.

[1] http://www.haskell.org/haskellwiki/Structure_of_a_Haskell_pr...

DanWaterworth4• 15 years ago

I'm the project's creator.

Haskell turned out to be a fantastic language to write this in; I especially liked how I was able to use the type system to separate out the levels of abstraction in the code base. I'm no stranger to implementing database like things and of the languages I've used in the past, I wouldn't favour any of them over Haskell in this setting.

I'll get right on to reorganization, it was on my todo list, but it's always more fun to add features instead. Thanks for taking the time to look at Siege.

tikhonj4• 15 years ago

Heh, glad to hear you liked using Haskell. It's a cool project; if I knew more about databases (I'm probably going to take a class on them soonish, but for now I'm completely ignorant) I'd look into it more deeply.

I completely understand not cleaning your code up--for some of my old projects in various languages, that's still on the todo list :) I just wanted to make sure you knew about that article--had I known it when starting some of my earlier projects, they would have been less of a mess initially. (Admittedly my last project was for a hackathon and was an unholy amalgamation of Haskell, Scala, JavaScript and a bit of Scheme; nothing could make that neat. :()

zohebv• 15 years ago

I have tried writing non-trivial Haskell programs in the past, but the IOMonad/lack of parameterized modules has stifled me.

Essentially, I start with basic code and possibly use some constants in the beginning. Eventually, I need the constants to be loaded from a config file or command line and now a huge swath of my code, which was perfectly pure, needs to be dragged into the IO Monad and the refactoring effort involved is huge, as no function that is even indirectly touching the so-called constant is now pure. This ends up being extremely painful. I have asked around and 2 suggestions I received, dump all my refactored functions inside a giant let clause, or wait for parameterized modules. How did you deal with this issue?

gregwebs2• 15 years ago

I actually think this is a very poor answer. This project is in its infancy and thus very easy to dismiss as vaporware, or if you actually used it you might come away with a bad impression (as you might with any alpha software). The question itself is ridiculous and should prompt some socratic questions (what do you think Haskell is designed for?). Like most programming languages, it is not designed for any particular domain, just for high-level programming, and it can excel at most domains once good libraries are created.

tikhonj4• 15 years ago

I'm not saying it's a valid complaint; however, I don't think it's uncommon. I think the person in question was assuming that Haskell was designed for mathy/programming languagey type stuff (I'm being vague and mangling English because I'm tired :)).

This is a great counter-example: it's a project in a different field and, most importantly, the programmer enjoyed using Haskell for it. As long as it at least mostly works, the actual quality and polish of the project is immaterial--you cannot really expect a spare-time project, even in a perfect language, to be perfect; its existence alone signals that Haskell is a viable multipurpose language that isn't just a silly academic curiosity.

dons3• 15 years ago

There's around four thousand packages on Hackage now (>2M loc); the last company I worked at had more than 1M lines of .hs; my current employer has maybe 800k lines of .hs

When does the no-non-trivial-code meme go away?

---

As an aside, I'm looking to hire a Haskell developer in NYC.

Strong computer science background, serious Haskell development experience (ideally be able to point at some Hackage libraries or apps you've written), math or financial modelling a plus.

Please contact me if you're interested.

tikhonj4• 15 years ago

Regarding your aside: I don't suppose you're also looking for an intern for the summer?

zht• 15 years ago

its

jasonlotito• 15 years ago

The name confused me. siege is actually a tool for web server stress testing. Not sure if this matters, but I read this as someone using siege to test the results from a DB written in Haskell.

aangjie• 15 years ago

Interesting.. I am looking to start with some hands-on haskell.. And DBMS is one topic am fluent with... Will try to contribute once i get it running on my ubuntu box.. Is the TODO the right place to start??

DanWaterworth4• 15 years ago

Hi, I'm the project's creator (and I also use ubuntu).

It's great to hear that you'd like to contribute. One of the things I'm trying to do is to expand the the subset of redis commands that it can respond to.

It should be simple to implement `strlen` ( http://redis.io/commands/strlen ), it just involves adding another clause to the readCommand function in Commands.hs and you can use `get` as a reference, but it should give you a taste of the codebase.

To anyone else reading this who'd also like to contribute, forks and pull requests are always welcome and there are plenty of other redis commands that I haven't got around to :)

derwiki• 15 years ago

When I was working on the database engine of Big Corporation, I kept thinking to myself that C was a poor choice. Sure, it's close to the metal -- but those gains are often lost by the incredible amount of complexity that is added. I always said a Python database with CPython modules would be almost as fast and 100x easier to maintain; glad to see someone took this further and did it in Haskell. Great work, Dan!

DanWaterworth4• 15 years ago

Actually, that's almost exactly the progression I took; C -> Python -> Haskell.

Siege, a DBMS written in Haskell

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