From: Jeff King <peff@peff.net>
Date: Thu, 19 Feb 2009 03:52:19 GMT
Subject: Re: tracking binary files
Message-ID: <20090219035219.GB19862@coredump.intra.peff.net>
In-Reply-To: <20090219031602.GD20416@b2j>

On Thu, Feb 19, 2009 at 11:16:02AM +0800, bill lam wrote:

> I would like to use git to track some database files of sizes from 1MB
> to 50MB.  I want to know does git compress them for storage or not.

Yes, git will compress them via zlib.

> If so, what will be the expected compression ratio.  Those files
> normally compressed to 25% of original size using zip.

Then I would expect the same ratio, since I believe zip and zlib both
use the "deflate" algorithm.

Note, however, that git will also do delta compression between versions.
So storing N versions of a file should be no _worse_ than zipping and
keeping those N versions. But if the database files have small enough
changes from version to version (which depends on the database format,
and how much the on-disk structure changes for each update) then it will
compress even more.

-Peff