From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Haggerty Subject: Re: [PATCH 4/6] introduce a commit metapack Date: Tue, 29 Jan 2013 11:24:45 +0100 Message-ID: <5107A36D.2050307@alum.mit.edu> References: <20130129091434.GA6975@sigill.intra.peff.net> <20130129091610.GD9999@sigill.intra.peff.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: git@vger.kernel.org, Duy Nguyen , "Shawn O. Pearce" To: Jeff King X-From: git-owner@vger.kernel.org Tue Jan 29 11:25:11 2013 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 1U08NK-000214-ST for gcvg-git-2@plane.gmane.org; Tue, 29 Jan 2013 11:25:11 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752997Ab3A2KYu (ORCPT ); Tue, 29 Jan 2013 05:24:50 -0500 Received: from ALUM-MAILSEC-SCANNER-1.MIT.EDU ([18.7.68.12]:44150 "EHLO alum-mailsec-scanner-1.mit.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751464Ab3A2KYs (ORCPT ); Tue, 29 Jan 2013 05:24:48 -0500 X-AuditID: 1207440c-b7fde6d00000088a-60-5107a36f1147 Received: from outgoing-alum.mit.edu (OUTGOING-ALUM.MIT.EDU [18.7.68.33]) by alum-mailsec-scanner-1.mit.edu (Symantec Messaging Gateway) with SMTP id F8.89.02186.F63A7015; Tue, 29 Jan 2013 05:24:47 -0500 (EST) Received: from [192.168.101.152] (ssh.berlin.jpk.com [212.222.128.135]) (authenticated bits=0) (User authenticated as mhagger@ALUM.MIT.EDU) by outgoing-alum.mit.edu (8.13.8/8.12.4) with ESMTP id r0TAOjgm002384 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Tue, 29 Jan 2013 05:24:46 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 In-Reply-To: <20130129091610.GD9999@sigill.intra.peff.net> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrCKsWRmVeSWpSXmKPExsUixO6iqJu/mD3Q4NVCNYuuK91MFt1T3jJa /GjpYbaYf2giqwOLx85Zd9k9nvXuYfT4c34Pq8fnTXIBLFHcNkmJJWXBmel5+nYJ3BkLbrIX fGGt+DxpH0sD41OWLkZODgkBE4n+N2fYIGwxiQv31gPZXBxCApcZJdrXrmMGSQgJHGeSeNrB AWLzCmhLfOj5yQpiswioSpy+ewHMZhPQlVjU08wEYosKhEn0vj7HCFEvKHFy5hOwZSICshLf D28EizMLZEps/LcEbL4w0BEL9h5lgdiVLtE9tQOshlPASmLz73dAcQ6genWJ9fOEIFrlJba/ ncM8gVFgFpINsxCqZiGpWsDIvIpRLjGnNFc3NzEzpzg1Wbc4OTEvL7VI11AvN7NELzWldBMj JJR5djB+WydziFGAg1GJh7d5AVugEGtiWXFl7iFGSQ4mJVHeWwvZA4X4kvJTKjMSizPii0pz UosPMUpwMCuJ8LrWAuV4UxIrq1KL8mFS0hwsSuK8qkvU/YAeSyxJzU5NLUgtgsnKcHAoSfBu WATUKFiUmp5akZaZU4KQZuLgBBnOJSVSnJqXklqUWFqSEQ+K0fhiYJSCpHiA9maBtPMWFyTm AkUhWk8x6nJs/93+nFGIJS8/L1VKnLcZpEgApCijNA9uBSxxvWIUB/pYmHcrSBUPMOnBTXoF tIQJaIlRG9iSkkSElFQDo6Y64/YmflO+/QuemT8/68ys81lla4b3ATYxZUf3043sBZZ8braP v87tKO5mOainfuevfQf//YdbPhq5TGL83Hn0gpmF+DH2zvmf3P0iknv6+hPSryeE Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: On 01/29/2013 10:16 AM, Jeff King wrote: > When we are doing a commit traversal that does not need to > look at the commit messages themselves (e.g., rev-list, > merge-base, etc), we spend a lot of time accessing, > decompressing, and parsing the commit objects just to find > the parent and timestamp information. We can make a > space-time tradeoff by caching that information on disk in a > compact, uncompressed format. > > TODO: document on-disk format in Documentation/technical > TODO: document API Would this be a good place to add the commit generation number that is so enthusiastically discussed on the mailing list from time to time? Michael -- Michael Haggerty mhagger@alum.mit.edu http://softwareswirl.blogspot.com/