One answer to blockchain scaling is sharding. Sharding promises to increase the throughput by changing the way blocks get validated by the network. The key feature of sharding that makes it unique among all (on-chain) scaling solutions is horizontal scaling, i.e., the throughput increases as the mining network expands. This particular characteristic of sharding may make it the ideal fuel to spur rapid adoption of blockchain technology.This article will briefly discuss the scaling issues with existing blockchain platforms — briefly only, because most readers must already be familiar with it. It will then discuss how sharding and its different forms can be a promising solution to the scaling problem. It will also touch upon some of the theoretical and practical challenges to implementing sharding and how some of these challenges can be overcome.Scalability Issues With Existing BlockchainsOne of the biggest problems that public blockchain platforms face today is scalability. All popular platforms are struggling to handle a larger number of transactions per second. In fact, today the public Ethereum and Bitcoin networks can handle 7-10 transactions per second on average. These figures are far inferior to those of centralized payment processors like Visa, which processes roughly 8,000 transactions per second on average.Slow transaction processing creates a major problem because they choke up the networks, making it difficult to use the blockchain for applications such as real-time payments. The longer a payment takes to be processed, the more inconvenient it becomes for the end user; this is one of the main reasons why payment methods like PayPal and credit cards like Visa are still much more attractive. As more complex DApps start to rely on the same network, the problems caused by slower transaction speed will only compound.From a more technical standpoint, all blockchain consensus protocols have a challenging limitation: Every fully participating node in the network must validate every transaction and must seek agreement from other nodes on it, and this is the component of blockchain technology that creates distributed ledgers and makes it secure.In most chains like Bitcoin and Ethereum, nodes are run by the public. While the decentralized consensus mechanism provides some vital advantages such as fault tolerance, security, political neutrality and authenticity, this method to verify chains comes at the cost of scalability. It will take more and more processing power to verify these public blockchains as they get larger, and this may create bottlenecks in these networks and slow down the creation of new applications. Sharding: Divide and ConquerSharding is a scaling technique that was inspired by a traditional concept of database sharding, whereby a
