Comments on: I’m Building Me A B-Tree

By: dete

dete — Mon, 07 Sep 2009 18:36:10 +0000

No; as far as I can tell there IS no real information about Prophet except in the code and the originator’s heads. To be fair, it’s obviously early days for the project and I’d rather they release something without docs than not release, but it’s hard not to be impatient: They’ve built something that I want to use RIGHT NOW… :-)

By: jens

jens — Mon, 07 Sep 2009 17:21:30 +0000

Perl’s not too popular these days, but everyone’s got their favorite language and I’m not going to begrudge them it. It does have the advantage that most OS’s already come with the runtime installed, which is more than you can say for CouchDB (written in Erlang.)

I wasn’t able to find any real information about Prophet, other than the slideshows and some sketchy notes in the doc/ subfolder. Do you know of any?

By: dete

dete — Mon, 07 Sep 2009 17:07:24 +0000

Yeah, Prophet seems promising… if one can easily bring the ideas into C/C++/Obj-C. Perl seems an odd choice these days, I thought Python was all the rage for “annoying to use in real software” development. (Haters: I’m kidding… mostly.)

If you don’t announce the release of the DB stuff, please shoot me an e-mail when it’s available. Thanks!

By: Jens Alfke

Jens Alfke — Sun, 06 Sep 2009 01:45:24 +0000

dete — I hadn’t heard of Prophet before, so thanks for the link! I’ve just opened the home page, and it looks pretty interesting. (Perl, though, yuck.)

Yes, my work’s going to be open-sourced, as soon as it’s stable. What I have now runs, but I keep refactoring all the code and jiggling the file format, so it’d be frustrating for anyone else to use.

In the past few weeks I’ve been focusing more on a hashtable version of the same thing, because I think we’re going to need that sooner at work, but the tree stuff is nearly as far along. (In principle both should be able to coexist in a file at the same time, with some more work.)

By: dete

dete — Sat, 05 Sep 2009 17:51:56 +0000

Any chance this stuff will get open-sourced?

We’ve got a couple of internal projects at my work that could really make use of a peer-to-peer database solution. (I didn’t even know that’s what we needed, but when I read about Prophet, I realized it was ideal…)

Anyhow, Prophet is Perl, which is embeddable, but hardly ideal for, say, an iPhone application. I considered rolling my own, and it would ideally be built on an append-only database like you’re talking about here (having an arbitrary history horizon is necessary for syncing).

The upshot is that I’d love to look at what you’re doing here!

BTW - I hates me the C++, but I agree that for code that requires portability, it’s probably the best choice.

By: Jens Alfke

Jens Alfke — Fri, 14 Aug 2009 21:38:43 +0000

Cody — Yeah, the deletion part is the hardest. Especially because the top-down type of B+tree doesn’t link the leaf nodes together.

(C++ is a little awkward, but I might want to use this for stuff at work.)

By: Dave Camp

Dave Camp — Fri, 14 Aug 2009 18:49:39 +0000

Back in the day, I implemented my own B*Tree code in C that mirrored the functionality of the HFS structures. It was for DiskFix, which was a disk repair utility that competed with Norton Utilities on the Mac (back when drive corruption was common in the System 7/8/9 days).

Fun! But also not Fun.

By: Cody Brimhall

Cody Brimhall — Fri, 14 Aug 2009 18:46:18 +0000

The last time I used C++ was back in University, where we were instructed to write (part of) a B-Tree. To make things easier on us, we didn’t have to implement a couple of funtions, delete() in particular—which disappointed me. The devil’s in the details, but so’s the fun!