Two Sides of the Same Coin: Large-scale Measurements of Builder and Rollup after EIP-4844

Web3 is reshaping decentralized ecosystems through innovations like Ethereum. Recently, EIP-4844 is implemented in Ethereum to support its Layer-2 scaling solutions, which introduces a new 128 KB data structure called blob. This upgrade incorporates type-3 transactions with blobs to verify data availability and reduce gas costs for rollups, significantly affecting the strategies of both builders and rollups. In this paper, we present an in-depth study of emerging strategies in builder and rollup markets after EIP-4844, containing hundred million transactions. We find that the efficiency of builder and rollup strategies is interdependent, akin to two sides of the same coin -- both cannot be optimized simultaneously. That is, when builders operate efficiently, rollups tend to overpay in fees, conversely, when rollups optimize their costs, builders may incur losses in inefficient transaction selection. From the side of builders, our results show that 29.48% of these blocks have been constructed inefficiently, which does not produce sufficient profits for builders. Through our evaluation from the side of rollups, we find that over 72.53% of type-3 transactions pay unnecessary fees, leading to notable economic costs of rollups. Our work provides critical insights into optimizing block construction and transaction strategies, advancing the economic efficiency and data scalability of Web3 infrastructures, yet, much like balancing a seesaw, the efficiency of builders and rollups cannot be optimized concurrently.