[Ethereum] the point of variable transaction fees in Ethereum (and Bitcoin as well)


After reading through the docs and through this post, I understand the concept and need for gas, but I do not understand why each transaction can have a variable fee associated with it. It seems to be a way for the rich to get priority over the poor, or those willing to pay a premium to get their transactions confirmed before anyone else. To me, this sounds unsustainable. Is there another reason for these changeable fees?

Best Answer

From the Yellow Paper

Transactors are free to specify any gasPrice that they wish, however miners are free to ignore transactions as they choose. A higher gas price on a transaction will therefore cost the sender more in terms of Ether and deliver a greater value to the miner and thus will more likely be selected for inclusion by more miners. Miners, in general, will choose to advertise the minimum gas price for which they will execute transactions and transactors will be free to canvas these prices in determining what gas price to offer. Since there will be a (weighted) distribution of minimum acceptable gas prices, transactors will necessarily have a trade-off to make between lowering the gas price and maximising the chance that their transaction will be mined in a timely manner.

Also found from Vtalik:


In my view it provides an elegant form of price discovery during periods of high contention for finite resources. For example, if we are hovering near the block gasLimit this is a mechanism for both users and miners to prioritize transaction urgency. I'm unsure what is unsustainable about that.