Re: Mercurial on BigTable

From: Shawn O. Pearce <spearce@spearce.org>
Date: Jun 12, 2009, 03:46 UTC
Message-ID: <20090612034645.GO16497@spearce.org>
In-Reply-To: <m34oun41pz.fsf@localhost.localdomain>

Jakub Narebski <jnareb@gmail.com> wrote:

Show 8 quoted lines

> Andreas Ericsson <ae@op5.se> writes:
> 
> > I'm more curious as to why they didn't choose git. The only explanation
> > that was actually true is that hg works well over HTTP 
> 
> Well, Google App Engine was in Python, so it follows that the crew
> would have it easier understanding Mercurial code (which is written in
> Python with parts in C for performance), and in moving it to BigTable.

This has nothing to do with Google AppEngine. GAE has CPU and bandwidth limitations in place that make running a source code server like Hg on it impossible. E.g. the maximum size you could download in a single HTTP request was 1 MB, now its up to 10 MB (IIRC). The Hg hosting runs in a different cluster than the GAE hosting does, and are managed by different teams.

> Adding Java to Gogle App Engine is, as far as I know, fairly recent;

True, yes, GAE Java support is fairly new.

> additionally JGit (git implementation in Java) is not yet full
> implementation.

JGit implements sufficient parts of Git to be a full server, and
could power a hosting site... indeed it powers Gerrit Code Review,
which some companies do use as their entire Git server solution,
rather than e.g. Gitosis.

-- 
Shawn.