Simulator

Only use the data of the mainnet to simulate transaction, and DONOT commit the final transaction to the mainnet.

Relay

To identify our transactions that need to simulate, if it’s failed then drop that tx, otherwise commit the final transaction to the mainnet.

Things need to consider:

  1. How to limit or identify transactions that need to simulate?

    Only execute the transactions from local txpool.

  2. Where to execute the transction previously?

    • Add a new RPC method to simuluate and then send the transaction(e.g. eth_simuluateAndSendTransaction / eth_simuluateAndSendRawTransaction).
    • Execute the transaction before we put the transaction into the txpool

  3. How to drop that transction from txpool?

    • Don’t put it into the txpool if the transaction is failed.

  4. Do transaction need to be signed?

  5. How to trace the changes during executing transaction? Query StateDB via two different state root.

Pre-execute before put tx into the txpool

  • The tx may not be seal into block if gas too low.

Pre-execute before put tx into the block

  • The tx may be sealed by another node because the txpool will be synchronized between nodes.