Hacker News Reader

Comment by tmlee | Hacker News Reader

Contract calls are executed by all the nodes in the network.

And they will all update the contract state onto their own blockchain then broadcast the result and compete via proof of work.

View on HN

I wonder how they can ever expect a system like this to scale given that every node has to execute every instruction in every called smart contract...

Scaling is definitely a serious concern and is a large focus of Ethereum developers at the moment. I don't understand much about the proposed solutions, but they generally think the Ethereum network can be sharded in a way that allows only a small subset of the network to run any given contract and still guarantee reliability similar to as if the whole network had run it.

You'll need some very hard guarantees that that 'small subset' can never be under the control of a single entity.

That's a good point. Bear in mind though that each subset can be larger than today's entire Ethereum or Bitcoin network.

It doesn't work like that - a working sharding scheme should not fail if one shard is taken over. This is the most recent description of ethereum sharding if you want to learn more -> https://youtu.be/9RtSod8EXn4?t=3h12m30s . In particular look at step 4 where the fork choice rule is changed so that shards with invalid blocks cannot exist on a valid base chain.

Also various more specialized schemes to run things offchain, and submit to the chain only the results and some kind of assurance that you ran them correctly. (E.g. Raiden, Plasma, TrueBit)

Reply on news.ycombinator.com