From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolas Pitre Subject: Re: git-gc "--aggressive" somewhat broken Date: Sun, 08 Jul 2007 23:46:44 -0400 (EDT) Message-ID: References: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=us-ascii Content-Transfer-Encoding: 7BIT Cc: Theodore Tso , Junio C Hamano , Git Mailing List To: Linus Torvalds X-From: git-owner@vger.kernel.org Mon Jul 09 05:46:58 2007 Return-path: Envelope-to: gcvg-git@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1I7kDB-0003W3-SA for gcvg-git@gmane.org; Mon, 09 Jul 2007 05:46:58 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758723AbXGIDqq (ORCPT ); Sun, 8 Jul 2007 23:46:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758679AbXGIDqq (ORCPT ); Sun, 8 Jul 2007 23:46:46 -0400 Received: from relais.videotron.ca ([24.201.245.36]:19221 "EHLO relais.videotron.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758631AbXGIDqp (ORCPT ); Sun, 8 Jul 2007 23:46:45 -0400 Received: from xanadu.home ([74.56.106.175]) by VL-MO-MR003.ip.videotron.ca (Sun Java System Messaging Server 6.2-2.05 (built Apr 28 2005)) with ESMTP id <0JKW00COK7TWK120@VL-MO-MR003.ip.videotron.ca> for git@vger.kernel.org; Sun, 08 Jul 2007 23:46:45 -0400 (EDT) In-reply-to: X-X-Sender: nico@xanadu.home Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: On Fri, 6 Jul 2007, Linus Torvalds wrote: > > > On Fri, 6 Jul 2007, Linus Torvalds wrote: > > > > If we want to be really aggressive, we migth decide to pass a new flag to > > pack-objects that does something closer to what "aggressive" was meant to > > do: it would use existing delta's if they exist, but _despite_ existing it > > could look if there are even better choices. > > This is a totally untested patch that may or may not work. > > The reason I say "may not work" is not just that I haven't really tested > it, it's also because I haven't thought it through very well. > > In particular, does this possibly cause infinite loops of delta chains? > Probably. It would need code to explicitly make sure that we don't do > that, but I couldn't even convince myself as to why we might not hit that > case _already_ with delta re-use, so maybe there's something going that > protects us against it. There is. > Anyway, consider this a starting point for somebody else who wants to > really try to look into this. This is a real teaser. But I have real work to do if I want to leave on vacation this summer, and therefore I'll then be on vacation. So if I end up looking at it myself it will be in September. Nicolas