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[207.236.125.16]) by smtp.gmail.com with ESMTPSA id h16sm897497qtx.20.2021.11.08.20.11.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 08 Nov 2021 20:11:25 -0800 (PST) From: Maxim Cournoyer References: <20211027034918.4591-1-maxim.cournoyer@gmail.com> <87o8795j61.fsf@gnu.org> <5c2dd60acfaa7d74b7554babb3e223bc855bac8a.camel@gmail.com> <87h7cxp9tl.fsf@gnu.org> <87sfwg7w9z.fsf@gmail.com> <87ee7tmdbd.fsf@gnu.org> Date: Mon, 08 Nov 2021 23:11:22 -0500 In-Reply-To: <87ee7tmdbd.fsf@gnu.org> ("Ludovic =?UTF-8?Q?Court=C3=A8s?="'s message of "Sat, 06 Nov 2021 17:57:58 +0100") Message-ID: <87k0hi0xzp.fsf@gmail.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: guix-patches@gnu.org List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-patches-bounces+larch=yhetil.org@gnu.org Sender: "Guix-patches" X-Migadu-Flow: FLOW_IN ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=yhetil.org; s=key1; t=1636431129; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding:resent-cc: resent-from:resent-sender:resent-message-id:in-reply-to:in-reply-to: references:references:list-id:list-help:list-unsubscribe: list-subscribe:list-post:dkim-signature; bh=kLECGrFl2ZF+KKyKoR9Z1g+7lY0MK3HG1Htt0LGjF44=; b=LfI1iLi+8WW7udBnu+sbXkRAOBHtV2/T6BhnrC8sU4vCeVuSj6/f7OIuOx751+ohEJsHDR kFYtqZEA1vOVCBF9S5VMk8dFR7UXJGiK4d5y9Iv7mz6QQnbMxw5lrm/aa4fqxcZtkkYfPy xH7mafjURuvEBSYQJnDa2gNz6k7oRObDg7/ntoG0j+U3XvplWPyNoaYbtyVmUD1215Itzj RCEprBYhWwStgAKqKSDKSB8Lel0eaus4snLZy30EQdNkocqs1GeFMAYqVqx/wRak5XqW/A rZ/bmHCFM4TdWVSIn0fvRjJJA+8aiAOk36oGqFKSAFxHCqq5NJlrQFebzRmw7Q== ARC-Seal: i=1; s=key1; d=yhetil.org; t=1636431129; a=rsa-sha256; cv=none; b=V15am0eGtF2QHP2jKdovILX71OUzcnyxm4YzT0jb6u9fJhlXV6Ip3/E1vUKuiFnE0BILW4 oxfHQZwu98gC8SUk3y2N5uExaPafcHQoHskWLscOWAA5JZ/rWOExkGuMjQjs6OY9Mv6Q3t 403BHxNR+KghJ0TRJxQXb6OyuR8Q+BLuQvYiWGEnZyANQw1Z00xiYbpxRna4pERfP7cm/F Kg4NIWtyc+/juK4eYCGHLSv9/o14G7RD3qPMIoHJ8mnGaTPrEFm3GmsIag6Gey+lhEEUFa TZxmjAhLvSmRF1KecY44Ch+KO7cmOEDEXKfaVpWaV//VUrdYgxYESdOCkahksQ== ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=fail ("headers rsa verify failed") header.d=gmail.com header.s=20210112 header.b=jJjWWla3; dmarc=fail reason="SPF not aligned (relaxed)" header.from=gmail.com (policy=none); spf=pass (aspmx1.migadu.com: domain of guix-patches-bounces@gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=guix-patches-bounces@gnu.org X-Migadu-Spam-Score: -1.32 Authentication-Results: aspmx1.migadu.com; dkim=fail ("headers rsa verify failed") header.d=gmail.com header.s=20210112 header.b=jJjWWla3; dmarc=fail reason="SPF not aligned (relaxed)" header.from=gmail.com (policy=none); spf=pass (aspmx1.migadu.com: domain of guix-patches-bounces@gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=guix-patches-bounces@gnu.org X-Migadu-Queue-Id: 3B4128B63 X-Spam-Score: -1.32 X-Migadu-Scanner: scn0.migadu.com X-TUID: s1FsDqaYAQAL Hi, Ludovic Court=C3=A8s writes: > Hi Maxim and all, > > Maxim Cournoyer skribis: > >> Ludovic Court=C3=A8s writes: > > [...] > >>> You seem to be proposing to remove =E2=80=98-D=E2=80=99 altogether. I = agree it has the >>> shortcomings you write, but I think it=E2=80=99s occasionally useful >>> nonetheless. >>> >>> My proposal would be either the status quo, or removing just the one >>> link that matters from /gnu/store/.links upon =E2=80=98-D=E2=80=99. >> >> The second proposal makes sense. > > Maybe that proposal is bogus though because you=E2=80=99d need to know th= e hash > of the files being removed, which means reading them=E2=80=A6 Oops :-). >> I didn't care about freeing space, as my use case was getting around >> corrupting an item in my store due to >> https://issues.guix.gnu.org/51400, which the patch proposed here >> allowed me to do without wasting hours of cleaning up links (nearly 1 >> GiB of store on spinning drives). > > The ideal solution as zimoun writes would be to address > . Seems there's some improvement ready, but which needs more testing/measurements? I'd suggest simply invoking GNU sort; if it has many pages of program for doing what it does, it's probably doing something fancier/faster than we can (are ready to) emulate -- for free! > Perhaps that phase needs to be implemented using a different strategy, > say an sqlite database that records the current link count (hoping that > =E2=80=98SELECT * FROM links WHERE NLINKS =3D 1=E2=80=99 would be faster = than traversing > all of =E2=80=98.links=E2=80=99) as well as a mapping from store item to = file hashes. Hmm. I'll need to dive in the problem a bit more before I can comment on this. > BTW, those using Btrfs can probably use =E2=80=98--disable-deduplication= =E2=80=99 and be > done with it. I erroneously used to think that Btrfs could do live deduplication, but it doesn't. There are external tools to do out of band / batch deduplication though [0]; so if they perform better than the guix daemon's own dedup, perhaps we could document this way out for our Btrfs users. [0] https://btrfs.wiki.kernel.org/index.php/Deduplication Thank you, Maxim