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 811101FA21 for ; Fri, 6 Oct 2017 04:02:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751025AbdJFECX (ORCPT ); Fri, 6 Oct 2017 00:02:23 -0400 Received: from pb-smtp1.pobox.com ([64.147.108.70]:61582 "EHLO sasl.smtp.pobox.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750757AbdJFECP (ORCPT ); Fri, 6 Oct 2017 00:02:15 -0400 Received: from sasl.smtp.pobox.com (unknown [127.0.0.1]) by pb-smtp1.pobox.com (Postfix) with ESMTP id 994AF9AFDF; Fri, 6 Oct 2017 00:02:14 -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=2fukWMqCGuL0Z4bqsMcnj56KfRE=; b=cfL9fH GU386OXIiLcNatMn4DZiyBz7vHn7blNs1jG8uC4F6UcyPXeDroG8352T1ZpATx6W 7XHUTra8CII31Lkt+2xKV5TOXRwUzMP4bcCw/WDrmMDAfrvOZoieggb3XjqVp+uu KLVwgVXttCxLCfqlPaSpfkq2onEh9UMK/+8Ok= 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=LB+n05g5SNJAwqoDWXZrlfsbg++KaOD9 1XyypIKQF/vdNawsuhwwvha6Twrf7mZjonU0dRtKnja9kuAhNv57ViJKOIo2MOVa mp1xYzVqeGoBJKkD448g6EyRFvJj7aTHk3Ywk/QzcVwfin0pRyQ81HI8UkcvlA0A VDyNdVFW+0U= Received: from pb-smtp1.nyi.icgroup.com (unknown [127.0.0.1]) by pb-smtp1.pobox.com (Postfix) with ESMTP id 90A879AFDD; Fri, 6 Oct 2017 00:02:14 -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-smtp1.pobox.com (Postfix) with ESMTPSA id CCAB29AFDC; Fri, 6 Oct 2017 00:02:13 -0400 (EDT) From: Junio C Hamano To: Jonathan Nieder Cc: Alex Vandiver , git@vger.kernel.org Subject: Re: [RFC] Reporting index properties References: <20171006031303.GB134987@aiede.mtv.corp.google.com> Date: Fri, 06 Oct 2017 13:02:12 +0900 In-Reply-To: <20171006031303.GB134987@aiede.mtv.corp.google.com> (Jonathan Nieder's message of "Thu, 5 Oct 2017 20:13:03 -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: 22A40D7A-AA4B-11E7-AC5E-8EF31968708C-77302942!pb-smtp1.pobox.com Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Jonathan Nieder writes: > Aside: git-update-index(1) says > > Version 4 is relatively young (first released in 1.8.0 in > October 2012). > > My first reaction is to wonder if it is time to introduce a config > option to use index format version 4 by default, since after 5 years > it is not relatively young any more. > > My second reaction is to notice that the index.version configuration > already exists. Probably git-update-index(1) ought to point to it. Both good points. > JGit still doesn't support index format 4, so 4 is still not a good > default for `index.version` for a user that hasn't explicitly > configured it, but the moment JGit gains that support I think it will > be. :) After reading ce_write_entry(), I tend to agree. v4 is the first one that loses the alignment padding, which made sense back when we mmap(2)ed the index file and read from it directly without the ondisk-vs-incore conversion, but that stopped to be the case several years ago. I find it interesting to find that the recently proposed design for reftable uses the same "common prefix compression from the previous name" trick, even though index v4 does not have any resync point like reftable does.