Subject: Re: [bitcoin-dev] Eli Dourado on "governance"

From: Anthony Towns <[email-masked]>
Date: Wed, 5 Aug 2015 00:22:19 +1000

On 4 August 2015 at 01:22, Gavin Andresen via bitcoin-dev <
[email-masked]> wrote:

> And the preliminary results of using a prediction market to try to wrestle
> with the tough tradeoffs looks roughly correct to me, too:
>    https://blocksizedebate.com/
>

​The scicast prediction market is shutdown atm (since early July?) so those
numbers aren't live. But...

Network hash rate
3,255.17 PH/s  (same block size)
5,032.64 PH/s  (block size increase)

4,969.68 PH/s  (no replace-by-fee)
3,132.09 PH/s  (replace-by-fee)

Those numbers seem completely implausible: that's ~2.9-3.6 doublings of the
current hashrate (< 400PH/s) in 17 months, when it's taken 12 months for
the last doubling, and there's a block reward reduction due in that period
too. (That might've been a reasonable prediction sometime in the past year,
when doublings were slowing from once every ~45 days to once a year; it
just doesn't seem a supportable prediction now)

That the PH/s rate is higher with bigger blocks is surprising, but given
that site also predicts USD/BTC will be $280 with no change but $555 with
bigger blocks, so I assume that difference is mostly due to price. Also,
12.5btc at $555 each is about 23 btc at $300 each, so if that price
increase is realistic, it would compensate for almost all of the block
reward reduction.

Daily transaction volume
168,438.22 tx/day  (same block size)
193,773.08 tx/day  (block size increase)

192,603.80 tx/day  (no replace-by-fee)
168,406.73 tx/day  (replace-by-fee)

That's only a 15% increase in transaction volume due to the block size
increase; I would have expected more? 168k-194k tx/day is also only a
30%-50% increase in transaction volume from 130k tx/day currently. If
that's really the case, then a 1.5MB-2MB max block size would probably be
enough for the next two years...

(Predicting that the node count will drop from ~5000 to ~1200 due to
increasing block sizes seems quite an indictment as far as centralisation
risks go; but given I'm not that convinced by the other predictions, I'm
not sure I want to give that much weight to that one either)

Cheers,
aj

-- 
Anthony Towns <[email-masked]>