From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-4.v43.ch3.sourceforge.com ([172.29.43.194] helo=mx.sourceforge.net) by sfs-ml-1.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1WYFpE-0006e4-2r for bitcoin-development@lists.sourceforge.net; Thu, 10 Apr 2014 14:19:32 +0000 Received-SPF: pass (sog-mx-4.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.223.171 as permitted sender) client-ip=209.85.223.171; envelope-from=laanwj@gmail.com; helo=mail-ie0-f171.google.com; Received: from mail-ie0-f171.google.com ([209.85.223.171]) by sog-mx-4.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1WYFpD-00054h-8j for bitcoin-development@lists.sourceforge.net; Thu, 10 Apr 2014 14:19:32 +0000 Received: by mail-ie0-f171.google.com with SMTP id ar20so4016868iec.2 for ; Thu, 10 Apr 2014 07:19:26 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.43.155.209 with SMTP id lj17mr689370icc.94.1397139565955; Thu, 10 Apr 2014 07:19:25 -0700 (PDT) Received: by 10.64.70.131 with HTTP; Thu, 10 Apr 2014 07:19:25 -0700 (PDT) In-Reply-To: References: Date: Thu, 10 Apr 2014 16:19:25 +0200 Message-ID: From: Wladimir To: Gregory Maxwell Content-Type: multipart/alternative; boundary=001a11c2fe1087d40104f6b0e799 X-Spam-Score: -0.6 (/) 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 (laanwj[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 X-Headers-End: 1WYFpD-00054h-8j Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Chain pruning 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: Thu, 10 Apr 2014 14:19:32 -0000 --001a11c2fe1087d40104f6b0e799 Content-Type: text/plain; charset=UTF-8 On Thu, Apr 10, 2014 at 2:10 PM, Gregory Maxwell wrote: > But sure I could see a fixed range as also being a useful contribution > though I'm struggling to figure out what set of constraints would > leave a node without following the consensus? Obviously it has > bandwidth if you're expecting to contribute much in serving those > historic blocks... and verifying is reasonably cpu cheap with fast > ecdsa code. Maybe it has a lot of read only storage? > The use case is that you could burn the node implementation + block data + a live operating system on a read-only medium. This could be set in stone for a long time. There would be no consensus code to keep up to date with protocol developments, because it doesn't take active part in it. I don't think it would be terribly useful right now, but it could be useful when nodes that host all history become rare. It'd allow distributing 'pieces of history' in a self-contained form. > I think it should be possible to express and use such a thing in the > protocol even if I'm currently unsure as to why you wouldn't do 100000 > - 200000 _plus_ the most recent 144 that you were already keeping > around for reorgs. > Yes, it would be nice to at least be able to express it, if it doesn't make the protocol too finicky. In terms of peer selection, if the blocks you need aren't covered by > the nodes you're currently connected to I think you'd prefer to seek > node nodes which have the least rare-ness in the ranges they offer. > E.g. if you're looking for a block 50 from the tip, you're should > probably not prefer to fetch it from someone with blocks 100000-150000 > if its one of only 100 nodes that has that range. > That makes sense. In general, if you want a block 50 from the tip, it would be best to request it from a node that only serves the last N (N>~50) blocks, and not a history node that could use the same bandwidth to serve earlier, rarer blocks to others. Wladimir --001a11c2fe1087d40104f6b0e799 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

= On Thu, Apr 10, 2014 at 2:10 PM, Gregory Maxwell <gmaxwell@gmail.com&= gt; wrote:
But sure I could see a fixed range as also b= eing a useful contribution
though I'm struggling to figure out what set of constraints would
leave a node without following the consensus? =C2=A0 Obviously it has
bandwidth if you're expecting to contribute much in serving those
historic blocks... and verifying is reasonably cpu cheap with fast
ecdsa code. =C2=A0 Maybe it has a lot of read only storage?

The use case is that you could burn the node implementation + blo= ck data + a live operating system on a read-only medium. This could be set = in stone for a long time.

There would be no consensus code to keep up to date with pro= tocol developments, because it doesn't take active part in it.

I don't think it would be terribly useful right no= w, but it could be useful when nodes that host all history become rare. It&= #39;d allow distributing 'pieces of history' in a self-contained fo= rm.
=C2=A0
I think it should be possible to express and use such a thing in the
protocol even if I'm currently unsure as to why you wouldn't do 100= 000
- 200000 =C2=A0_plus_ the most recent 144 that you were already keeping
around for reorgs.

Yes, it would be nic= e to at least be able to express it, if it doesn't make the protocol to= o finicky.

In terms of peer selection, if the blocks you need aren't covered by the nodes you're currently connected to I think you'd prefer to see= k
node nodes which have the least rare-ness in the ranges they offer.
E.g. if you're looking for a block 50 from the tip, =C2=A0you're sh= ould
probably not prefer to fetch it from someone with blocks 100000-150000
if its one of only 100 nodes that has that range.

=
That makes sense.

In general, if you want a block 50 fro= m the tip, it would be best to request it from a node that only serves the = last N (N>~50) blocks, and not a history node that could use the same ba= ndwidth to serve earlier, rarer blocks to others.

Wladimir

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