Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 82FD95AC for ; Wed, 16 Nov 2016 14:32:27 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-it0-f52.google.com (mail-it0-f52.google.com [209.85.214.52]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 5B330286 for ; Wed, 16 Nov 2016 14:32:26 +0000 (UTC) Received: by mail-it0-f52.google.com with SMTP id l8so66717285iti.1 for ; Wed, 16 Nov 2016 06:32:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=z261v7BmfYofnQIYBmI+tgrueSlc4N7kiFY162Oxoc4=; b=A/0fNCkL1QaFBku+JvZ/dQwzk34Iw4Eogy/m0ll1BpJY4ASiRumt1UlSl5CXLGrw9M SvCKx2yDlm1f2ozWHPd9RoFDVwEG8UAn/QPeWunDjipDDRDVOGq1DPM24wQbiS21iQlO yUqi+ObIMVWwreL4QxKEEiWHFvbIjlK0tUDDfvNuPFyd+fTFUq7/PlmWTa5BvVtLmYrU qfu0wrIhiSGgZdJRjwuLxreNTdfKkeT5XdZgkDbMlSe9W/8HXIi6qphzQH8CswvVtFOg 5IRNsSk/qheiOaMhb6JP0nxArJ1I8UXCBOO1tDvijTdvofZYA7yvxlAdut9u0bpbD8aj 5n0g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=z261v7BmfYofnQIYBmI+tgrueSlc4N7kiFY162Oxoc4=; b=QUelTUq2ouL6lKdm4wVUbiqYWU/W8vAxw6O+RKymF+lq/X+5H08pipSsm/w1sANePO 6vVGcQvbOYsGKVD8xbS53pnZvPMzHKaJcGf5jvb4S1nK+Khdpaucixd+isiGSu4HBKZC bjO6IaPAJ4Hq5CVtIvULiLvmzG3jlXa9ZkrWZRKzMfdHfBhQSavxvupZTdJ2Wy3Dxi0D k0WWAKlCKXMYGrIwXtU7dNQIgU/0ExuVQbi47O1HtWsE/qIiaJcfMTGL93/48I4QYElG V/rodebhF3Xf5CZ/xV8Yb3JKWrgtJrH7MgBBkh6vK9jO/Fz8qz56FIGD++B6TfWW6Ysa xF1Q== X-Gm-Message-State: ABUngvczMMRy8CBCAZ8U3x7sdRAdZ12X8VxNkGpRGwSdhPPhlCPD283/QCKzVd79BLvXd673XIC1V5rdlHALcA== X-Received: by 10.107.23.134 with SMTP id 128mr2547654iox.162.1479306745666; Wed, 16 Nov 2016 06:32:25 -0800 (PST) MIME-Version: 1.0 Received: by 10.64.119.199 with HTTP; Wed, 16 Nov 2016 06:32:24 -0800 (PST) In-Reply-To: References: <33BFC318-0BB4-48DB-B5DC-08247FAC6E5A@voskuil.org> From: Alex Morcos Date: Wed, 16 Nov 2016 09:32:24 -0500 Message-ID: To: Tier Nolan , Bitcoin Protocol Discussion Content-Type: multipart/alternative; boundary=94eb2c05b14a16e4d905416bf1d4 X-Spam-Status: No, score=-1.5 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, HTML_MESSAGE, RCVD_IN_DNSWL_NONE, RCVD_IN_SORBS_SPAM autolearn=no version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Subject: Re: [bitcoin-dev] [BIP Proposal] Buried Deployments X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 16 Nov 2016 14:32:27 -0000 --94eb2c05b14a16e4d905416bf1d4 Content-Type: text/plain; charset=UTF-8 I think we are misunderstanding the effect of this change. It's still "OK" for a 50k re-org to happen. We're just saying that if it does, we will now have potentially introduced a hard fork between new client and old clients if the reorg contains earlier signaling for the most recent ISM soft fork and then blocks which do not conform to that soft fork before the block height encoded activation. I think the argument is this doesn't substantially add to the confusion or usability of the system as its likely that old software won't even handle 50k block reorgs cleanly anyway and there will clearly have to be human coordination at the time of the event. In the unlikely event that the new chain does cause such a hard fork, that coordination can result in everyone upgrading to software that supports the new rules anyway. So no, I don't think we should add a checkpoint. I think we should all just agree to a hard fork that only has a very very slim chance of any practical effect. In response to Thomas' email. I think ideally we would treat these soft forks the way we did BIP30 which is to say that we're just introducing a further soft fork that applies to all blocks except for the historical exceptions. So then its a almost no-op soft fork with no risk of hard fork. This however isn't practical with at least BIP 34 without storing the hashes of all 200K blocks that don't meet the requirement. On Wed, Nov 16, 2016 at 9:18 AM, Tier Nolan via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org> wrote: > On Wed, Nov 16, 2016 at 1:58 PM, Eric Voskuil via bitcoin-dev < > bitcoin-dev@lists.linuxfoundation.org> wrote: > >> Are checkpoints good now? Are hard forks okay now? >> > > I think that at least one checkpoint should be included. The assumption > is that no 50k re-orgs will happen, and that assumption should be directly > checked. > > Checkpointing only needs to happen during the headers-first part of the > download. > > If the block at the BIP-65 height is checkpointed, then the comparisons > for the other ones are automatically correct. They are unnecessary, since > the checkpoint protects all earlier block, but many people would like to be > able to verify the legacy chain. > > This makes the change a soft-fork rather than a hard fork. Chains that > don't go through the checkpoint are rejected but no new chains are allowed. > > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > > --94eb2c05b14a16e4d905416bf1d4 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
I think we are misunderstanding the effect of this change.=
It's still "OK" for a 50k re-org to happen.
We= 're just saying that if it does, we will now have potentially introduce= d a hard fork between new client and old clients if the reorg contains earl= ier signaling for the most recent ISM soft fork and then blocks which do no= t conform to that soft fork before the block height encoded activation.

I think the argument is this doesn't substantiall= y add to the confusion or usability of the system as its likely that old so= ftware won't even handle 50k block reorgs cleanly anyway and there will= clearly have to be human coordination at the time of the event.=C2=A0 In t= he unlikely event that the new chain does cause such a hard fork, that coor= dination can result in everyone upgrading to software that supports the new= rules anyway.

So no, I don't think we should = add a checkpoint.=C2=A0 I think we should all just agree to a hard fork tha= t only has a very very slim chance of any practical effect.

<= /div>
In response to Thomas' email.=C2=A0 I think ideally we would = treat these soft forks the way we did BIP30 which is to say that we're = just introducing a further soft fork that applies to all blocks except for = the historical exceptions.=C2=A0 So then its a almost no-op soft fork with = no risk of hard fork. =C2=A0 This however isn't practical with at least= BIP 34 without storing the hashes of all 200K blocks that don't meet t= he requirement.



On Wed, Nov 16, 2016 at 9:18 AM, Ti= er Nolan via bitcoin-dev <bitcoin-dev@lists.linuxfound= ation.org> wrote:
On Wed, Nov 16, 2016 at 1:58 PM, Eric Voskuil via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wr= ote:
Are che= ckpoints good now? Are hard forks okay now?

I think that at least one checkpoint should be included.=C2= =A0 The assumption is that no 50k re-orgs will happen, and that assumption = should be directly checked.

Checkpointing only needs to happen durin= g the headers-first part of the download.

If the block at= the BIP-65 height is checkpointed, then the comparisons for the other ones= are automatically correct.=C2=A0 They are unnecessary, since the checkpoin= t protects all earlier block, but many people would like to be able to veri= fy the legacy chain.

This makes the= change a soft-fork rather than a hard fork.=C2=A0 Chains that don't go= through the checkpoint are rejected but no new chains are allowed.

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bitcoin-dev@lists.= linuxfoundation.org
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