Citation

Pugatsov, A., Ileri, C. U., Decouchant, J. “The Blockchain Execution Dilemma: Optimizing Revenue XOR Fair Ordering.” arXiv:2604.23266v1 [cs.DC] (25 Apr 2026). Delft University of Technology / IOTA Foundation.

Core Question

As DAG consensus pushes the bottleneck to the execution layer, transaction sequencing (not just parallel execution) becomes decisive. The paper studies the tension between validator revenue and order fairness as a dynamic optimization problem in a continuous execution model where block executions can overlap.

Method

  • Blockchain-independent sequencing-layer model (the layer between consensus and execution that schedules txs across workers and manages congestion via deferral), building on Sui’s defer-on-congestion design.
  • An anytime genetic algorithm that sequences using gas prices, object (read/write) sets, and predicted execution times — integrating execution-time + object-conflict data into the initial ordering, not just the deferral phase.
  • Optional fair-ordering constraint: non-independent txs are always executed in consensus-determined causal order; independent txs may be reordered.
  • Evaluated on real Sui data and synthetic Ethereum data, with perturbed execution-time predictions.

Headline Results

  • Genetic sequencer raises validator profit ~15% vs the gas-price greedy baseline and clears congestion up to 58% faster (50–60% faster congestion relief).
  • Enforcing strict fair ordering reduces validator revenue 50–60% during high congestion.
  • First evidence that strict fair ordering effectively nullifies the advantages of advanced sequencing — the two paradigms sit at opposite ends of a spectrum (discretionary, opaque validator control vs rigid arrival-order fairness).

Why It Matters

See Also