This problem has been a focus of intense debate, rigorous research, and media attention for the last few years. This is the single most important problem that could mean the difference between wider adaptability of blockchains or limited private use only by consortiums. As a result of substantial research in this area, many solutions have been proposed, which are discussed in the following section.
From a theoretical perspective, the general approach toward tackling the scalability issue generally revolves around protocol-level enhancements. For example, a commonly mentioned solution to bitcoin scalability is to increase its block size. Other proposals include off-chain solutions that offload certain processing to off-chain networks, for example, off-chain state networks. Based on the solutions mentioned above, generally, the proposals can be divided into two categories: on-chain solutions that are based on the idea of changing fundamental protocols on which the blockchain operates...