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From: Junio C Hamano <gitster@pobox.com>
Subject: Re: Git's database structure
Date: Thu, 06 Sep 2007 02:09:58 -0700
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Cc: Jon Smirl <jonsmirl@gmail.com>,
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To: Andreas Ericsson <ae@op5.se>
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Andreas Ericsson <ae@op5.se> writes:

> Estimated daily uses of git-blame, world-wide: few
> Estimated daily uses of git-{merge,diff}, worldwide: lots

Which makes the author of git-blame weep X-<.

The real issue is that embedding pathname in blob does _not_
help "git blame" but would actively hurt it.  A file with the
identical contents moved between the parent to child commit
shares the same blob object and same object name in the real
git.  Jon's modified system that hashes pathname together with
the contents would have them as two completely unrelated objects
with different object names, which only means that even 100%
similarity rename case becomes as expensive to find as renames
of lower similarity, which needs to expand and look into blob
contents.