eth_call base on specific block & specific index

[huahuayu]

hi, eth_call can be executed query/tx in a specific block as this method shows

go-ethereum/ethclient/ethclient.go

Line 475 in c503f98

func (ec *Client) CallContract(ctx context.Context, msg ethereum.CallMsg, blockNumber *big.Int) ([]byte, error) {

is it possible to execute eth_call in a specific block AND a specific index?

I happened to see this service, it can fork chain at a specific block and index, which is really cool!

and then I can do simulation

how can I implement it in the native go-ethereum current codebase?

[nebojsa94]

Hey @huahuayu,

We have a custom EVM that is more flexible than standard JSON-RPC interface, but you can definitely accomplish this with go-ethereum.

Basically, instead of just opening StateDB at a certain block number you also need to apply all transactions with an index lower than provided index.

Keep in mind that this requires an archive node if you want to perform eth_call on old blocks (more than 128 blocks in the past) and that applying transactions can take a bit more time (up to 300-400ms) depending on the index.

[huahuayu]

@nebojsa94 thanks for the reply, your tools are great!

Exactly the same thought in my mind :) It can be realized by archive node + ganache-cli fork + execute lower index tx in sequence.

[huahuayu]

could this be native support in geth, it should be useful @karalabe