From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-4.0 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD shortcircuit=no autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 983E22036B for ; Wed, 4 Oct 2017 01:44:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751408AbdJDBoR (ORCPT ); Tue, 3 Oct 2017 21:44:17 -0400 Received: from pb-smtp2.pobox.com ([64.147.108.71]:60773 "EHLO sasl.smtp.pobox.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751171AbdJDBoQ (ORCPT ); Tue, 3 Oct 2017 21:44:16 -0400 Received: from sasl.smtp.pobox.com (unknown [127.0.0.1]) by pb-smtp2.pobox.com (Postfix) with ESMTP id 924529E749; Tue, 3 Oct 2017 21:44:15 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; s=sasl; bh=hPAzBCHRqA/99KqkihakNHoFLMs=; b=w05CaF Yjgc8WNSoA/xVYABBBKQmtNlHyJmYqd/Q2nfPcwYARE2IiE507jJCPVfPYBC0AVS 88vKcZU7Ta/J0lHpPL4Dq/iV4y4pPsNGsVsWrpUhtmjSYYJdlAGfcF7f2GAWnbhl P+IrkFMfuLRDTBt7QlG7u6XZEpATxmqhnnNa0= DomainKey-Signature: a=rsa-sha1; c=nofws; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; q=dns; s=sasl; b=mBPCjoJQdXwZXRrzIV8YbxPixTVEAOHT VSEW9umG9itCFdpwa+B3wKwsQwhFI2r9hZNs81b9ID9EBCD3t5XPNHV9C3Y/vx72 Cc1v4PrNKeiP0RPQuKS/RVmyxd4n6R9Y/PJs+38FZBd6pvUlT6ZuhlIyfdR5nAoW MkVTJSTtsT8= Received: from pb-smtp2.nyi.icgroup.com (unknown [127.0.0.1]) by pb-smtp2.pobox.com (Postfix) with ESMTP id 890EA9E747; Tue, 3 Oct 2017 21:44:15 -0400 (EDT) Received: from pobox.com (unknown [104.132.0.95]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by pb-smtp2.pobox.com (Postfix) with ESMTPSA id ED38C9E746; Tue, 3 Oct 2017 21:44:14 -0400 (EDT) From: Junio C Hamano To: Jonathan Nieder Cc: Shawn Pearce , Linus Torvalds , Git Mailing List , Stefan Beller , bmwill@google.com, Jonathan Tan , Jeff King , David Lang , "brian m. carlson" , Masaya Suzuki , demerphq@gmail.com, The Keccak Team , Johannes Schindelin Subject: Re: [PATCH v4] technical doc: add a design doc for hash function transition References: <20170304011251.GA26789@aiede.mtv.corp.google.com> <20170307001709.GC26789@aiede.mtv.corp.google.com> <20170928044320.GA84719@aiede.mtv.corp.google.com> Date: Wed, 04 Oct 2017 10:44:13 +0900 In-Reply-To: <20170928044320.GA84719@aiede.mtv.corp.google.com> (Jonathan Nieder's message of "Wed, 27 Sep 2017 21:43:21 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Pobox-Relay-ID: 87444F30-A8A5-11E7-89A7-575F0C78B957-77302942!pb-smtp2.pobox.com Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Jonathan Nieder writes: > +Alternatives considered > +----------------------- > +Upgrading everyone working on a particular project on a flag day > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > ... > +Using hash functions in parallel > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > ... Good that we are not doing these ;-) > +Lazily populated translation table > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > +Some of the work of building the translation table could be deferred to > +push time, but that would significantly complicate and slow down pushes. > +Calculating the sha1-name at object creation time at the same time it is > +being streamed to disk and having its newhash-name calculated should be > +an acceptable cost. And the version described in the body of the document hopefully would be simpler. It certainly would be, when SHA-1 content and NewHash content are the same (i.e. blob). THanks.