Re:Bitcoin Energy Consumption Index
by decentralised on Sunday August 27, 2017 @01:00AM
(#15109216)
> The mining algorithm cares not one bit about number of transactions
Actually it does to some extent because the transaction hashes are used to calculate the block header hash.
Yes, but the hashing of the merkle tree to obtain the merkle root takes like 10^4 hashes for 10^3 transactions.
Compared with 2^80 that is about the number of hash operations needed to find a POW block header, it it trascurable.
Re:Bitcoin Energy Consumption Index
by decentralised on Sunday August 27, 2017 @02:51AM
(#15109492)
I'm not sure about that calculation to be honest. The merkle root is very simple to calculate and verify that's why it's so useful. The POW difficulty is in finding a hash starting with the right number of zeroes and containing the previous block header hash.
Did i get this wrong?
Re:Bitcoin Energy Consumption Index
by imnotatwork on Sunday August 27, 2017 @06:41AM
(#15110142)
No, you're right.
Numbers i said are my guesses, but the order of magnitude should be about that.
I don't remember exactly how many hash ops you have to do to put 1000 txes in a merkle tree, but it should be more than 1000 and less than 10000.
My point was exactly that. Computational cost of the merkle tree is negligible when confronted with the computational cost of the POW
You're only kind of right. The mining algorithm cares not one bit about number of transactions, so higher tx volume has no direct effect on the mining energy expenditure. But it does have a second order effect.
More transactions usually entails higher fees (as people compete for block space to put their transactions in). More fees means higher mining rewards, means higher incentive to mine, means more mining activity, and, therefore, higher energy expenditure.