From mboxrd@z Thu Jan 1 00:00:00 1970 From: esr@thyrsus.com (Eric S. Raymond) Subject: Millisecond precision in timestamps? Date: Tue, 27 Nov 2012 15:48:28 -0500 (EST) Message-ID: <20121127204828.577264065F@snark.thyrsus.com> To: git@vger.kernel.org X-From: git-owner@vger.kernel.org Tue Nov 27 21:48:50 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 1TdS5I-0002VP-UT for gcvg-git-2@plane.gmane.org; Tue, 27 Nov 2012 21:48:49 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755522Ab2K0Usc (ORCPT ); Tue, 27 Nov 2012 15:48:32 -0500 Received: from static-71-162-243-5.phlapa.fios.verizon.net ([71.162.243.5]:57614 "EHLO snark.thyrsus.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752755Ab2K0Usc (ORCPT ); Tue, 27 Nov 2012 15:48:32 -0500 Received: by snark.thyrsus.com (Postfix, from userid 1000) id 577264065F; Tue, 27 Nov 2012 15:48:28 -0500 (EST) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Because I do a lot of work on repository conversion tools, I've had to learn a lot of detail about ontological mismatches between version-control systems - especially places where you lose metadata moving between them. In general, git metadata can carry forward almost all the metadata in a Subversion repository. Among the handful of minor exceptions (empty directories, flow structure, certain kinds of mergeinfos) there is one that stands out because it seems to be an implementation detail rather than a consequence of fundamentally different design decisions. I refer to the one-second precision of git timestamps. Subversion stores its commit and property-change timestamps to microsecond precision; conversion tools have to throw the subsecond part of this information away. Has going to timestamps with the full precision of the system clock been considered and rejected, or am I the first to bring this up? If I were to write refactoring patches that treated "timestamp" as an ADT, with a view towards hiding the difference between int and float timestamps and eventually experimenting with float ones, would they be accepted? -- Eric S. Raymond Every Communist must grasp the truth, 'Political power grows out of the barrel of a gun.' -- Mao Tse-tung, 1938, inadvertently endorsing the Second Amendment.