Re: [PATCH 1/3] Lazily open pack index files on demand

From: Shawn O. Pearce <spearce@spearce.org>
Date: May 27, 2007, 21:35 UTC
Message-ID: <20070527213525.GC28023@spearce.org>
In-Reply-To: <alpine.LFD.0.99.0705271127110.3366@xanadu.home>

Nicolas Pitre <nico@cam.org> wrote:

Show 14 quoted lines

> On Sat, 26 May 2007, Dana How wrote:
> 
> > On 5/26/07, Shawn O. Pearce <spearce@spearce.org> wrote:
> > > In pack v4 we're likely to move the SHA-1 table from the .idx file
> > > into the front of the .pack file.  This makes the .idx file hold
> > > only the offsets and the CRC checkums of each object.  If we start
> > > making a super index, we have to duplicate the SHA-1 table twice
> > > (once in the .pack, again in the super index).
> > 
> > Hmm, hopefully the SHA-1 table can go at the _end_
> > since with split packs that's the only time we know the number
> > of objects in the pack... ;-)
> 
> Hmmm good point to consider.

The problem with putting the SHA-1 table at the end of the pack is it ruins the streaming for both unpack-objects and index-pack if we were to ever use pack v4 as a transport format. Or just try to run a pack v4 packfile through unpack-objects, just locally, say to extract megablobs. ;-)

-- 
Shawn.