Return-Path: Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id 21501C0051 for ; Sat, 19 Sep 2020 19:46:41 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id 1012A86FD9 for ; Sat, 19 Sep 2020 19:46:41 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id mqsSm8vnBVq9 for ; Sat, 19 Sep 2020 19:46:40 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from outgoing.mit.edu (outgoing-auth-1.mit.edu [18.9.28.11]) by hemlock.osuosl.org (Postfix) with ESMTPS id F0E0B86FD7 for ; Sat, 19 Sep 2020 19:46:39 +0000 (UTC) Received: from mail-ed1-f47.google.com (mail-ed1-f47.google.com [209.85.208.47]) (authenticated bits=0) (User authenticated as jlrubin@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 08JJkbtf018216 (version=TLSv1/SSLv3 cipher=AES128-GCM-SHA256 bits=128 verify=NOT) for ; Sat, 19 Sep 2020 15:46:38 -0400 Received: by mail-ed1-f47.google.com with SMTP id t16so9210030edw.7 for ; Sat, 19 Sep 2020 12:46:38 -0700 (PDT) X-Gm-Message-State: AOAM533nJhRNQ+eoM0yRySo36hcA+5NJrDa0Y7v9vyIDMZqfA6m67yJ9 y+7SR8VCCN7AVMahI7affDLrC46hevt5zN0an4Q= X-Google-Smtp-Source: ABdhPJzzuOut7RUGYTfSqndolEuo1BW26BARfmF1hel7KHI+6pSEDpwxCAV1HdbQ51ZXdvFMA4n+HVfZK8saCZ+4ocg= X-Received: by 2002:a05:6402:1558:: with SMTP id p24mr43792799edx.194.1600544797223; Sat, 19 Sep 2020 12:46:37 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Jeremy Date: Sat, 19 Sep 2020 12:46:25 -0700 X-Gmail-Original-Message-ID: Message-ID: To: Antoine Riard Content-Type: multipart/alternative; boundary="00000000000015f02105afafe07a" Cc: Bitcoin Protocol Discussion Subject: Re: [bitcoin-dev] A Replacement for RBF and CPFP: Non-Destructive TXID Dependencies for Fee Sponsoring X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 19 Sep 2020 19:46:41 -0000 --00000000000015f02105afafe07a Content-Type: text/plain; charset="UTF-8" Antoine, Yes I think you're a bit confused on where the actual sponsor vector is. If you have a transaction chain A->B->C and a sponsor S_A, S_A commits to txid A and A is unaware of S. W.r.t your other points, I fully agree that the 1-to-N sponsored case is very compelling. The consensus rules are clear that sponsor commitments are non-rival, so there's no issue with allowing as many sponsors as possible and including them in aggregate. E.g., if S_A and S'_A both sponsor A with feerate(S*) > feerate(A), there's no reason not to include all of them in a block. The only issue is denial of service in the mempool. In the future, it would definitely be desirable to figure out rules that allow mempools to track both multiple sponsors and multiple sponsor targets. But in the interest of KISS, the current policy rules are designed to be minimally invasive and maximally functional. In terms of location for the sponsor vector, I'm relatively indifferent. The annex is a possible location, but it's a bit odd as we really only need to allow one such vector per tx, not one per input, and one per input would enable some new use cases (maybe good, maybe bad). Further, being in the witness space would mean that if two parties create a 2 input transaction with a desired sponsor vector they would both need to specify it as you can't sign another input's witness data. I wholeheartedly agree with the sentiment though; there could be a more efficient place to put this data, but nothing jumps out to me as both efficient and simple in implementation (a new tx-level field sounds like a lot of complexity). > n >=1 ? I think you can have at least one vector and this is matching the code yes, this has been fixed in the gist (cred to Dmitry Petukhov for pointing it out first), but is correct in the code. Thank you for your careful reading. --00000000000015f02105afafe07a Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Antoine,

Y= es I think you're a bit confused on where the actual sponsor vector is.= If you have a transaction chain A->B->C and a sponsor S_A, S_A commi= ts to txid A and A is unaware of S.


W.r.t your other points, I fully agree that the 1-to-N s= ponsored case is very compelling. The consensus rules are clear that sponso= r commitments are non-rival, so there's no issue with allowing as many = sponsors as possible and including them in aggregate. E.g., if S_A and S= 9;_A both sponsor A with feerate(S*) > feerate(A), there's no reason= not to include all of them in a block. The only issue is denial of service= in the mempool. In the future, it would definitely be desirable to figure = out rules that allow mempools to track both multiple sponsors and multiple = sponsor targets. But in the interest of KISS, the current policy rules are = designed to be minimally invasive and maximally functional.

In = terms of location for the sponsor vector, I'm relatively indifferent. T= he annex is a possible location, but it's a bit odd as we really only n= eed to allow one such vector per tx, not one per input, and one per input w= ould enable some new use cases (maybe good, maybe bad). Further, being in t= he witness space would mean that if two parties create a 2 input transactio= n with a desired sponsor vector they would both need to specify it as you c= an't sign another input's witness data. I wholeheartedly agree with= the sentiment though; there could be a more efficient place to put this da= ta, but nothing jumps out to me as both efficient and simple in implementat= ion (a new tx-level field sounds like a lot of complexity).


> n >=3D1 = ? I think you can have at least one vector and this is matching the code

yes, this has been fixed in the=C2=A0gist (cred to Dmitry Petukho= v for pointing it out first), but is correct in the code. Thank you for you= r careful reading.

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