Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1Sh2v2-0001E0-8i for bitcoin-development@lists.sourceforge.net; Tue, 19 Jun 2012 18:12:48 +0000 Received-SPF: pass (sog-mx-2.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.160.175 as permitted sender) client-ip=209.85.160.175; envelope-from=etotheipi@gmail.com; helo=mail-gh0-f175.google.com; Received: from mail-gh0-f175.google.com ([209.85.160.175]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-MD5:128) (Exim 4.76) id 1Sh2v1-0007yl-J2 for bitcoin-development@lists.sourceforge.net; Tue, 19 Jun 2012 18:12:48 +0000 Received: by ghbz2 with SMTP id z2so5055387ghb.34 for ; Tue, 19 Jun 2012 11:12:42 -0700 (PDT) Received: by 10.236.75.3 with SMTP id y3mr24101641yhd.110.1340129562129; Tue, 19 Jun 2012 11:12:42 -0700 (PDT) Received: from [192.168.1.85] (c-76-111-96-126.hsd1.md.comcast.net. [76.111.96.126]) by mx.google.com with ESMTPS id y66sm82220136yhi.10.2012.06.19.11.12.41 (version=SSLv3 cipher=OTHER); Tue, 19 Jun 2012 11:12:41 -0700 (PDT) Message-ID: <4FE0C103.3070304@gmail.com> Date: Tue, 19 Jun 2012 14:12:19 -0400 From: Alan Reiner User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Gregory Maxwell References: <4FE0B7EB.6000100@gmail.com> In-Reply-To: Content-Type: multipart/alternative; boundary="------------070000040605000202080204" X-Spam-Score: -0.8 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (etotheipi[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 1.0 HTML_MESSAGE BODY: HTML included in message -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.2 AWL AWL: From: address is in the auto white-list X-Headers-End: 1Sh2v1-0007yl-J2 Cc: bitcoin-development@lists.sourceforge.net Subject: Re: [Bitcoin-development] Ultimate Blockchain Compression w/ trust-free lite node X-BeenThere: bitcoin-development@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 19 Jun 2012 18:12:48 -0000 This is a multi-part message in MIME format. --------------070000040605000202080204 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 06/19/2012 01:59 PM, Gregory Maxwell wrote: > On Tue, Jun 19, 2012 at 1:33 PM, Alan Reiner wrote: >> One app developer updates their >> RB tree code which updated the RB-tree optimizations/rebalancing, and >> now a significant portion of the network can't agree on the correct >> root. Not only would that be disruptive, it would be a disaster to >> track down. > This is why good comprehensive tests and a well specified algorithim > are important. The tree update algorithm would be normative in that > scheme. Worrying that implementers might get it wrong would be like > worrying that they'd get SHA256 wrong. The point is not that they get it *wrong*, it's that the implement it *differently*. Given a set of 100 TxOuts, there's a seemingly-infinite number of ways to construct a binary tree. Put them in in a different order, and you get a different tree. *They're all correct and legal* in terms of satisfying expectations of insert, delete and query runtime -- but they will produce different root hashes. And the differences in underlying structure are completely transparent to the calling code. I'm extremely uncomfortable with the idea the you can have all the nodes in the tree, but have to replay X years of blockchain history just to get the same tree configuration as someone else. However, a trie configuration is history-independent -- given an unspent-TxOut list, there's only one way to construct that tree. That's an important property to me. I can't tell if you're joking about Judy structures: I've never heard of them. But I'll look into it anyway... --------------070000040605000202080204 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit On 06/19/2012 01:59 PM, Gregory Maxwell wrote:
On Tue, Jun 19, 2012 at 1:33 PM, Alan Reiner <etotheipi@gmail.com> wrote:
 One app developer updates their
RB tree code which updated the RB-tree optimizations/rebalancing, and
now a significant portion of the network can't agree on the correct
root.  Not only would that be disruptive, it would be a disaster to
track down.
This is why good comprehensive tests and a well specified algorithim
are important. The tree update algorithm would be normative in that
scheme. Worrying that implementers might get it wrong would be like
worrying that they'd get SHA256 wrong.

The point is not that they get it wrong, it's that the implement it differently.  Given a set of 100 TxOuts, there's a seemingly-infinite number of ways to construct a binary tree.  Put them in in a different order, and you get a different tree.  They're all correct and legal in terms of satisfying expectations of insert, delete and query runtime -- but they will produce different root hashes.   And the differences in underlying structure are completely transparent to the calling code.

I'm extremely uncomfortable with the idea the you can have all the nodes in the tree, but have to replay X years of blockchain history just to get the same tree configuration as someone else.  However, a trie configuration is history-independent -- given an unspent-TxOut list, there's only one way to construct that tree.  That's an important property to me.

I can't tell if you're joking about Judy structures: I've never heard of them.  But I'll look into it anyway...

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