Re: git repository size / compression

From: Andreas Krey <a.krey@gmx.de>
Date: Sep 9, 2011, 17:49 UTC
Message-ID: <20110909174937.GA6057@inner.h.iocl.org>
In-Reply-To: <CAEBDL5U5-1nBGbWtb6+CfBrESoy8+p0Qqw1t1n_5EKFmpq9NhA@mail.gmail.com>

On Fri, 09 Sep 2011 12:05:03 +0000, John Szakmeister wrote: ...

> will at times choose to self-compress the file, instead of doing a
> delta and compressing.  IIRC, there is some heuristics in there for
> determining when to do that, but I forget the exact method.

Don't know about the compression part, but subversion does a delta of the nth version of a file (not the global revision number n) against the version m, where m is (n & (n-1)), or the least significant '1' bit flipped to '0'. That way, there are only O(log(n)) instead of O(n) deltas to apply to get at a specific version.

[Was on the svn users list just then. They described it differently,
 but in essence it's that.]

Andreas

-- 
"Totally trivial. Famous last words."
From: Linus Torvalds <torvalds@*.org>
Date: Fri, 22 Jan 2010 07:29:21 -0800