From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nguyen Thai Ngoc Duy Subject: Re: [GSoC] Designing a faster index format Date: Wed, 21 Mar 2012 17:34:15 +0700 Message-ID: References: <8D287169-1AD9-4586-BDBC-F820220328FC@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: git@vger.kernel.org To: Thomas Gummerer X-From: git-owner@vger.kernel.org Wed Mar 21 11:34:54 2012 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1SAIsX-0001az-Mc for gcvg-git-2@plane.gmane.org; Wed, 21 Mar 2012 11:34:54 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758354Ab2CUKer (ORCPT ); Wed, 21 Mar 2012 06:34:47 -0400 Received: from mail-wi0-f172.google.com ([209.85.212.172]:46289 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758334Ab2CUKeq (ORCPT ); Wed, 21 Mar 2012 06:34:46 -0400 Received: by wibhj6 with SMTP id hj6so6307105wib.1 for ; Wed, 21 Mar 2012 03:34:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; bh=bpnE1jOWd1Cp4ZHwGzIKH0FfD6OvjVijipFJLppK8N8=; b=ot9/e0c0BbPq9nL67HsqhheD9hQ0n8arRNWpNDbplNPg2CaiINKodNXkhXbiFHhMPI K7RltAgXYksCxpjc6fM0Wz3wY/F+N4LK8zVo1OIs5LiGhNYBp5Jc7xuCFrhPpPw3dI+m HpzQianhScKDnx6Lea7aHVw9E0gi1G3bPK0mF+KaacY6LFLlljjkHOT0/mu9qNL3YSNH v9IcCOMH6uVPjwpOe7hvSmGFY+qEsI5lDH1yrCK0M5kyAZw0Ll75k1zXcGqHoDfVBBK4 sqaI5lDDRPixcAUGiGQWgjgBsifzRILPWjYB8LBzbsJuphcjNiZZ8e6Uu7D33sRaBTkZ whOw== Received: by 10.180.80.40 with SMTP id o8mr7782840wix.10.1332326085506; Wed, 21 Mar 2012 03:34:45 -0700 (PDT) Received: by 10.223.109.144 with HTTP; Wed, 21 Mar 2012 03:34:15 -0700 (PDT) In-Reply-To: <8D287169-1AD9-4586-BDBC-F820220328FC@gmail.com> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: On Wed, Mar 21, 2012 at 4:22 PM, Thomas Gummerer wrote: > > On Mar 21, 2012, at 2:29 AM, Nguyen Thai Ngoc Duy wrote: > >> On Wed, Mar 21, 2012 at 4:17 AM, Thomas Gummerer wrote: >>> There are some questions I would have about the project. >>> Has there already been any development or thoughts in that direction? >> >> Tree-based format seems to be favored by core developers, for example >> in the footnote in [1]. But there have been no attempts to realize it. >> You may want to search mail archive for more. >> > > Thanks for your answer, so I would probably implement a tree based structure. There may be a better approach, maybe a simple database format that we could immitate. It's up to you to find out :) > However I got one more question, since I'm not yet really familiar with the > code and internal structure of git, what exactly does the SHA1 over the > index exactly achieve? Is it only for checking if the index is still correct > for the next time it is used and has not been changed or is there a more > important function of it? It makes sure the index is not corrupt (by disk faults for example). I don't think it is used for anything else. Cheaper checksum can be used if good enough for the index. See http://thread.gmane.org/gmane.comp.version-control.git/190016 and the following reply. -- Duy