While plasma minimizes the load on the blockchain by bundling multiple transactions into a single, on-chain transaction, sharding results in parallelization of blockchain.
According to Buterin
“The ethereum blockchain as it currently exists can support 15 transactions a second. I think that with software improvements alone, ethereum style blockchains can probably get up to possibly 100 or so. Then you have sharding. The first version of sharding is what we call quadratic sharding. If every computer can do n things per second, we have n shards, and then each shard has n transactions.
Basically a computer will have to process all the shards, which is n units of work, one shard is also n unit of work, so you can have a network made out of those computers, but the network itself has n squared capacity all-together.
If you plug in the constants, then you can get to something like 100 shards, where each of the shards has that amount of capacity, so you possibly get to 10,000 transactions a second.Then you can go to potentially super quadratic sharding which is layering that structure on top of itself, then scalability can go into hundreds of thousands and millions and so forth. But there are natural upper bounds from the number of users, from certain safety properties that do not easily scale quadratically.
So I do expect sharded systems to get to tens of thousands, hundreds of thousands, eventually, but there is a bit of an upper limit. And then on top of that, Plasma, state channels, I do expect to be possibly something like a 2 to 3 order of magnitude gain in the long term once everything runs squeaky and smooth.
You can also look at the question of how much scalability we need from the demand side. The ethereum blockchain does 15 transactions a second, Uber does 12 rides a second, the major stock exchanges go up to about 80,000 transactions a second, and then if we talk about the future where we have 25 billion IoT devices by 2025… that’s probably going to go into a million, low millions of operations per second. Especially if you go into non-financial stuff, the volume goes way up.
So, I think that approximate figure of something in the low millions is sort of the intersection of what is feasible to get to with technology improvements and also kind of the upper limit of what people want.”
According to Buterin, billions of transactions per second would be quite comfortable to deal with, but is not absolutely necessary. Buterin believes that a few million transactions per second will be more than enough and it can be achieved by beginning with 10,000 to 100,000 transactions per second using sharding. Once plasma protocol is implemented, the number of transactions per second can easily increase 10x of what is achieved with sharding technique.
OmiseGo
The discussion did not reveal any time frame for sharding to become a reality. Hybrid Casper is currently being tested. Once the test gets completed successfully, we can assume that it may be implemented with the Metropolis upgrade. From then on, the focus will be solely on sharding. So, if everything goes as per plan, we can expect sharding sometime in 2019.
Buterin also made a noteworthy comment about blockchain’s rising prominence in the world where protective forces work for their own vested interests. He said:
“In recent times, especially with this wave of nationalism, anti-globalism, these recent internet regulatory changes… it’s harder to build a website for the world. It’s more about are you going to be available inside the EU, or you not, or you’re going to be available inside the US, will you be available inside of China, what about Russia. The more places you’re running in, the more regulatory compliance overhead you have and so forth.
There’s definitely a lot of dangers to that trend that I’m worried about. Especially that kind of, the internet’s potential as what a lot of us originally intended it to be, as something to bring the world closer together, is something that is under threat to some extend.
I do see blockchains, with their radically open, permissionless and worldwide nature, as being, at least, a possible part of the antidote to that trend. Not just because of their open accessibility and censorship resistance, but also because blockchain applications can scale the entire world.
The way that they’re doing it is instead of being something that starts in one place and then becomes part of that place, sort of trying to take over the world in a certain sense with that place being at the centre, it’s more like, people in a lot of different places and in a lot of different countries, environments, companies, organizations, tribes, whatever, basically all coming together and then linking together with each other horizontally at the same time. I do think that general approach can be an antidote to a lot of the problems that we are facing today.”