Solana's Plan for Fairer Trades Hits Roadblock

Solana's proposed rule to make trades fairer has stalled as block producers still choose which orders get in. The SIMD-0649 pull request closed on September 25 without merging, leaving the narrower trade-off for further discussion.

The proposed consensus check would make the order of transactions within each completed batch inspectable and enforceable, but it would not establish one priority queue for an entire slot. Non-exempt transactions in each batch would have to appear in non-increasing priority order based on their reward divided by their requested cost under the pre-execution cost model.

The draft specifies that a validator replaying the block would compare their recorded priorities and treat a violation as an invalid block, but it would not reshuffle transactions into the right sequence after receiving them. The proposal aims to give an observer a testable answer to one question: among non-exempt transactions that a leader placed in the same batch, was the recorded order consistent with the proposed score?