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Date: Tue, 25 Mar 2014 08:45:00 -0400
Message-ID: <CABsx9T149f9of9+sYMFazAxtRi=ZJrpA1B41buERD3+j7NGKmg@mail.gmail.com>
From: Gavin Andresen <gavin@bitcoinfoundation.org>
To: Peter Todd <pete@petertodd.org>
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Cc: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] Tree-chains preliminary summary
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On Tue, Mar 25, 2014 at 8:28 AM, Peter Todd <pete@petertodd.org> wrote:

> Bitcoin doesn't scale. There's a lot of issues at hand here, but the
> most fundemental of them is that to create a block you need to update
> the state of the UTXO set, and the way Bitcoin is designed means that
> updating that state requires bandwidth equal to all the transaction
> volume to keep up with the changes to what set. Long story short, we get
> O(n^2) scaling, which is just plain infeasible.
>

We have a fundamental disagreement here.

If you go back and read Satoshi's original thoughts on scaling, it is clear
that he imagined tens of thousands of mining nodes and hundreds of millions
of lightweight SPV users.

Scaling is a problem if every person is a fully validating node; then,
indeed, you get an O(n^2) problem.  Which can be solved by extending some
tentative trust to your peers, but lets put all those possible solutions
aside.

Given tens of thousands of fully validating nodes, you get O(m*n), where m
is the number of fully validating peers and is a large constant (10s of
thousands).

We don't know how large m can or will be; we have only just started to
scale up.

"Bitcoin doesn't scale" is pure FUD. It might not scale in exactly the way
you want, but it WILL scale.

-- 
--
Gavin Andresen
Chief Scientist, Bitcoin Foundation
https://www.bitcoinfoundation.org/

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<div dir=3D"ltr"><div class=3D"gmail_extra">On Tue, Mar 25, 2014 at 8:28 AM=
, Peter Todd <span dir=3D"ltr">&lt;<a href=3D"mailto:pete@petertodd.org" ta=
rget=3D"_blank">pete@petertodd.org</a>&gt;</span> wrote:<br></div><div clas=
s=3D"gmail_extra">
<div class=3D"gmail_quote"><blockquote class=3D"gmail_quote" style=3D"margi=
n:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div id=3D":oh" c=
lass=3D"a3s" style=3D"overflow:hidden">Bitcoin doesn&#39;t scale. There&#39=
;s a lot of issues at hand here, but the<br>

most fundemental of them is that to create a block you need to update<br>
the state of the UTXO set, and the way Bitcoin is designed means that<br>
updating that state requires bandwidth equal to all the transaction<br>
volume to keep up with the changes to what set. Long story short, we get<br=
>
O(n^2) scaling, which is just plain infeasible.<br></div></blockquote></div=
><br>We have a fundamental disagreement here.</div><div class=3D"gmail_extr=
a"><br></div><div class=3D"gmail_extra">If you go back and read Satoshi&#39=
;s original thoughts on scaling, it is clear that he imagined tens of thous=
ands of mining nodes and hundreds of millions of lightweight SPV users.</di=
v>
<div class=3D"gmail_extra"><br></div><div class=3D"gmail_extra">Scaling is =
a problem if every person is a fully validating node; then, indeed, you get=
 an O(n^2) problem. =A0Which can be solved by extending some tentative trus=
t to your peers, but lets put all those possible solutions aside.</div>
<div class=3D"gmail_extra"><br></div><div class=3D"gmail_extra">Given tens =
of thousands of fully validating nodes, you get O(m*n), where m is the numb=
er of fully validating peers and is a large constant (10s of thousands).</d=
iv>
<div class=3D"gmail_extra"><br></div><div class=3D"gmail_extra">We don&#39;=
t know how large m can or will be; we have only just started to scale up.<b=
r><br>&quot;Bitcoin doesn&#39;t scale&quot; is pure FUD. It might not scale=
 in exactly the way you want, but it WILL scale.<br clear=3D"all">
<div><br></div>-- <br>--<div>Gavin Andresen</div><div>Chief Scientist, Bitc=
oin Foundation</div><div><a href=3D"https://www.bitcoinfoundation.org/" tar=
get=3D"_blank">https://www.bitcoinfoundation.org/</a></div><div><br></div>
</div></div>

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