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Date: Sun, 27 Sep 2015 17:10:24 +0200
Message-ID: <CAPswA9xFNgdbH1JXBx+CqjT5HbkK0WGaWQLrJzm+BJCmrXRQcA@mail.gmail.com>
From: Kalle Rosenbaum <kalle@rosenbaum.se>
To: Bitcoin Dev <bitcoin-dev@lists.linuxfoundation.org>
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Subject: Re: [bitcoin-dev] Weak block thoughts...
Precedence: list

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I was mansplaining weak blocks to my wife. She asked a simple question:

Why would I, as a miner, publish a weak block if I find one?

I don't know.

Sure, I will get faster propagation for my solved block, should I find one.
On the other hand everybody else mining a similar block will enjoy the same
benefit. Assuming that I'm not a huge miner, it's unlikely that I will
actually solve the block, so I'm probably just giving away fast propagation
times to someone else.

So how does publishing a weak block benefit the producer of it more than
the other miners? Please help me understand this.

/Kalle Rosenbaum


2015-09-27 11:42 GMT+02:00 Tier Nolan via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org>:

>
>
> On Sun, Sep 27, 2015 at 2:39 AM, Gregory Maxwell via bitcoin-dev <
> bitcoin-dev@lists.linuxfoundation.org> wrote:
>
>> Unless the weak block transaction list can be a superset of the block
>> transaction list size proportional propagation costs are not totally
>> eliminated.
>>
>
> The POW threshold could be dynamic.  The first weak-block that builds on a
> new block could be forwarded with a smaller target.
>
> This reduces  the window size until at least one weak block is
> propagated.
>
> The change in threshold could be time based (for the first 30 seconds or
> so).  This would cause a surge of traffic when a new block once a new block
> has propagated, so perhaps not so good an idea.
>
>
>> As even if the weak block criteria is MUCH lower than the block
>> criteria (which would become problematic in its own right at some
>> point) the network will sometimes find blocks when there hasn't been
>> any weak block priming at all (e.g. all prior priming has made it into
>> blocks already).
>>
>
> If there is a transaction backlog, then miners could forward merkle
> branches with transactions in the memory pool with a commitment in the
> coinbase.
>
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>
>

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<div dir=3D"ltr">I was mansplaining weak blocks to my wife. She asked a sim=
ple question:=C2=A0<div><br></div><div>Why would I, as a miner, publish a w=
eak block if I find one?<div><br></div><div>I don&#39;t know.</div><div><br=
></div><div>Sure, I will get faster propagation for my solved block, should=
 I find one. On the other hand everybody else mining a similar block will e=
njoy the same benefit. Assuming that I&#39;m not a huge miner, it&#39;s unl=
ikely that I will actually solve the block, so I&#39;m probably just giving=
 away fast propagation times to someone else.</div><div><br></div><div>So h=
ow does publishing a weak block benefit the producer of it more than the ot=
her miners? Please help me understand this.</div><div><br></div><div>/Kalle=
 Rosenbaum</div></div><div><br></div><div class=3D"gmail_extra"><br><div cl=
ass=3D"gmail_quote">2015-09-27 11:42 GMT+02:00 Tier Nolan via bitcoin-dev <=
span dir=3D"ltr">&lt;<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.or=
g" target=3D"_blank">bitcoin-dev@lists.linuxfoundation.org</a>&gt;</span>:<=
br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left=
:1px #ccc solid;padding-left:1ex"><div dir=3D"ltr"><br><div class=3D"gmail_=
extra"><br><div class=3D"gmail_quote"><span>On Sun, Sep 27, 2015 at 2:39 AM=
, Gregory Maxwell via bitcoin-dev <span dir=3D"ltr">&lt;<a href=3D"mailto:b=
itcoin-dev@lists.linuxfoundation.org" target=3D"_blank">bitcoin-dev@lists.l=
inuxfoundation.org</a>&gt;</span> wrote:<br><blockquote class=3D"gmail_quot=
e" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">=
<span>
</span>Unless the weak block transaction list can be a superset of the bloc=
k<br>
transaction list size proportional propagation costs are not totally<br>
eliminated.<br></blockquote><div><br></div></span><div>The POW threshold co=
uld be dynamic.=C2=A0 The first weak-block that builds on a new block could=
 be forwarded with a smaller target.<br><br></div><div>This reduces=C2=A0 t=
he window size until at least one weak block is propagated.=C2=A0 <br><br><=
/div><div>The change in threshold could be time based (for the first 30 sec=
onds or so).=C2=A0 This would cause a surge of traffic when a new block onc=
e a new block has propagated, so perhaps not so good an idea.<br></div><spa=
n><div><br></div><div></div><blockquote class=3D"gmail_quote" style=3D"marg=
in:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
As even if the weak block criteria is MUCH lower than the block<br>
criteria (which would become problematic in its own right at some<br>
point) the network will sometimes find blocks when there hasn&#39;t been<br=
>
any weak block priming at all (e.g. all prior priming has made it into<br>
blocks already).<br></blockquote><div><br></div></span><div>If there is a t=
ransaction backlog, then miners could forward merkle branches with transact=
ions in the memory pool with a commitment in the coinbase.<br></div></div><=
/div></div>
<br>_______________________________________________<br>
bitcoin-dev mailing list<br>
<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" target=3D"_blank">=
bitcoin-dev@lists.linuxfoundation.org</a><br>
<a href=3D"https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev" =
rel=3D"noreferrer" target=3D"_blank">https://lists.linuxfoundation.org/mail=
man/listinfo/bitcoin-dev</a><br>
<br></blockquote></div><br></div></div>

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