A decentralized state machine that can transfer 1,000,000 unique tokens on Uniswap in a single atomic transaction. How?
- UXTO-like storage. Transactions only lock the parts of state they modify, there is no global state lock like in EVM.
- ...distributed. Instead of every node storing the entire state, we partition the data in the same way Google's Bigtable/Spanner scales to trillions of rows.
- ...decoupled from execution. STARK proofs are the answer - self-contained transactions that prove the storage leaves they updated, in
O(log N)time.
- Multi-version concurrency control.
- Transactional memory.
- Google Bigtable - horizontal sharding via sorting by key and partitioning on row range.
- Google Spanner - TrueTime API.
- Bitcoin - POW/difficulty as a BFT clock - compared against TrueTime.
- State models - UXTO (parallelisable), account-based - akin to a global interpreter lock.
- Models of computation - replicated state machines, verifier-prover.
There are many axes you can compare blockchains against:
- Transactional bandwidth: how much compute units (gas) of capacity does that chain offer to process per second? Is the memory model amenable to parallelisation (UXTO, Solana)?
- Storage costs and limits: how much does persistent storage cost? In nearly every chain (BTC, EVM, SOL), every node must store the entire system state, which makes storage extremely expensive.
- Execution costs and limits: how much does execution/compute cost? In nearly every chain, every node must run the full transaction for O(N) cost. In STARK/SNARK systems, execution cost is generally O(log^2 N).
- Scalability: when the chain reaches the limits of storage/execution, how do you scale further? Bridges are the ugliest solution. IBC works only marginally better. Neither are atomically composable - it is always worse to interact cross-chain than it is to interact within the chain.