From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sam Vilain Subject: Re: [PATCH] Change 'Deltifying objects' to 'Delta compressing objects' Date: Fri, 19 Oct 2007 15:55:30 +1300 Message-ID: <47181CA2.5010605@vilain.net> References: <20071019004527.GA12930@spearce.org> <20071019021255.GD3290@coredump.intra.peff.net> <47181430.2080907@vilain.net> <20071019023645.GC8298@coredump.intra.peff.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: David Symonds , "Shawn O. Pearce" , git@vger.kernel.org, Nicolas Pitre To: Jeff King X-From: git-owner@vger.kernel.org Fri Oct 19 04:55:52 2007 Return-path: Envelope-to: gcvg-git-2@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1Iii1e-0004bH-I9 for gcvg-git-2@gmane.org; Fri, 19 Oct 2007 04:55:51 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759281AbXJSCzj (ORCPT ); Thu, 18 Oct 2007 22:55:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758983AbXJSCzj (ORCPT ); Thu, 18 Oct 2007 22:55:39 -0400 Received: from watts.utsl.gen.nz ([202.78.240.73]:48549 "EHLO magnus.utsl.gen.nz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757360AbXJSCzi (ORCPT ); Thu, 18 Oct 2007 22:55:38 -0400 Received: by magnus.utsl.gen.nz (Postfix, from userid 65534) id E6221205ACC; Fri, 19 Oct 2007 15:55:36 +1300 (NZDT) Received: from [192.168.2.22] (leibniz.catalyst.net.nz [202.78.240.7]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by magnus.utsl.gen.nz (Postfix) with ESMTP id 4D65B21CFDB; Fri, 19 Oct 2007 15:55:32 +1300 (NZDT) User-Agent: Icedove 1.5.0.12 (X11/20070606) In-Reply-To: <20071019023645.GC8298@coredump.intra.peff.net> X-Enigmail-Version: 0.94.2.0 X-Spam-Checker-Version: SpamAssassin 3.0.2 (2004-11-16) on mail.magnus.utsl.gen.nz X-Spam-Level: X-Spam-Status: No, score=-2.8 required=5.0 tests=ALL_TRUSTED autolearn=failed version=3.0.2 Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: Jeff King wrote: > On Fri, Oct 19, 2007 at 12:24:44PM +1000, David Symonds wrote: > >> Forward thinking, that's probably most sensible, since git 4.7 might >> not use delta compression, but maybe wavelet compression, or other >> scheme entirely. Using deltas is an implementation detail, after all. > > Git already uses two types of compression (zlib on all objects, deltas > between objects in packfiles). So just saying "compressing" is actually > a bit ambiguous, and I think noting that what we are _actually_ doing > right now is delta compression is worthwhile. True. But then, zlib compression is also delta compressing and huffman coding. Git's delta compression is quite similar; it just uses a larger window than the sliding 64k gzip one. Sam.`