From mboxrd@z Thu Jan  1 00:00:00 1970
From: Junio C Hamano <gitster@pobox.com>
Subject: Re: Performance issue of 'git branch'
Date: Wed, 22 Jul 2009 21:40:36 -0700
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Linus Torvalds <torvalds@linux-foundation.org> writes:

> On Wed, 22 Jul 2009, Linus Torvalds wrote:
>> 
>> Ooh yes. That would do it. It's going to peel and look up every single ref 
>> it finds, so it's going to look up _hundreds_ of objects (all the tags, 
>> all the commits they point to, etc etc). Even if it then only shows a 
>> couple of branches.
>> 
>> Junio, any ideas?
>
> I had one of my own.

It seems that I missed all the fun while going out to dinner.

> It uses the "raw" version of 'for_each_ref()' (which doesn't verify that 
> the ref is valid), and then does the "type verification" before it starts 
> doing any gentle commit lookup.

Hmm, we now have to remember what this patch did, if we ever wanted to
introduce negative refs later (see ef06b91 do_for_each_ref: perform the
same sanity check for leftovers., 2006-11-18).  Not exactly nice to spread
the codepaths that need to be updated.  Is the cold cache performance of
"git branch" to list your local branches that important?