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=-6.7 required=3.0 tests=AWL,BAYES_00, 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 2A62E1FEAA for ; Sat, 25 Jun 2016 02:53:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751568AbcFYCxD (ORCPT ); Fri, 24 Jun 2016 22:53:03 -0400 Received: from dcvr.yhbt.net ([64.71.152.64]:38646 "EHLO dcvr.yhbt.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751524AbcFYCxC (ORCPT ); Fri, 24 Jun 2016 22:53:02 -0400 Received: from localhost (dcvr.yhbt.net [127.0.0.1]) by dcvr.yhbt.net (Postfix) with ESMTP id F13DF1FE4E; Sat, 25 Jun 2016 02:53:00 +0000 (UTC) Date: Sat, 25 Jun 2016 02:53:00 +0000 From: Eric Wong To: Jeff King Cc: Junio C Hamano , git@vger.kernel.org Subject: Re: [RFC] gc: correct gc.autoPackLimit documentation Message-ID: <20160625025300.GA29053@dcvr.yhbt.net> References: <20160625011450.GA14293@dcvr.yhbt.net> <20160625020620.GA31290@sigill.intra.peff.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20160625020620.GA31290@sigill.intra.peff.net> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Jeff King wrote: > On Sat, Jun 25, 2016 at 01:14:50AM +0000, Eric Wong wrote: > > > I'm not sure if this is the best approach, or if changing > > too_many_packs can be done without causing problems for > > hosts of big repos. > > > > -------8<----- > > Subject: [PATCH] gc: correct gc.autoPackLimit documentation > > > > I want to ensure there is only one pack in my repo to take > > advantage of pack bitmaps. Based on my reading of the > > documentation, I configured gc.autoPackLimit=1 which led to > > "gc --auto" constantly trying to repack on every invocation. > > I'm not sure if you might be misinterpreting earlier advice on bitmaps > here. At the time of packing, bitmaps need for all of the objects to go > to a single pack (they cannot handle a case where one object in the pack > can reach another object that is not in the pack). But that is easily > done with "git repack -adb". > > After that packing, you can add new packs that do not have bitmaps, and > the bitmaps will gracefully degrade. E.g., imagine master was at tip X > when you repacked with bitmaps, and now somebody has pushed to make it > tip Y. Somebody then clones, asking for Y. The bitmap code will start > at Y and walk backwards. When it hits X, it stops walking as it can fill > in the rest of the reachability from there. Ah, thanks, makes sense. I was misinterpreting earlier advice on bitmaps. > That's neither here nor there for the off-by-one in gc or its > documentation, of course, but just FYI. I'm now inclined to fix the problem in gc and leave the documentation as-is (unless it cause other problems...)