Sharding in Seele

1. Introduction

To increase the capacity of Seele, we partition the Seele network into 4 shards. In each shard there is an independent blockchain. Transactions can be made across shards. The cross-shard transaction is also called debt.

The difference between regular transactions and debts is that regular transactions happen between two accounts on the same shard while debts happen between two accounts on different shards.

Under $GOPATH\src\github.com\seeleteam\go-seele\cmd\node\config\, we have 4 nodes: node1.json, node2.json, node3.json, node4.json. Each json file corresponds to the configuration of one shard. They are used to run Seele nodes. For details, see How to customize your node configurations.

2. How to send debt

  • You need an account with value to transfer (for example, 100000 fan) from shard1 account to shard2 account.
shard1 account: 0x4c10f2cd2159bb432094e3be7e17904c2b4aeb21
shard2 account: 0xd228e1dd02bdce9656b8e195a77e0da0b70daea1

In go-seele/cmd/client

// Request
client sendtx --from .keystore-shard1-0x4c10f2cd2159bb432094e3be7e17904c2b4aeb21 --to 0xd228e1dd02bdce9656b8e195a77e0da0b70daea1 --amount 100000
Please input your key file password:
account: 0x4c10f2cd2159bb432094e3be7e17904c2b4aeb21, transaction nonce: 1
transaction sent successfully
{
        "Hash": "0x07d874cad8305bdcb813221425725d0c4ce651a20420e98cc0e911e181ae1da1",
        "Data": {
                "From": "0x4c10f2cd2159bb432094e3be7e17904c2b4aeb21",
                "To": "0xd228e1dd02bdce9656b8e195a77e0da0b70daea1",
                "Amount": 100000,
                "AccountNonce": 1,
                "GasPrice": 10,
                "GasLimit": 42000,
                "Timestamp": 0,
                "Payload": ""
        },
        "Signature": {
                "Sig": "CyeAgd+RgPnb27XJXOWT8CnbtwSmyDMJ6oIEFKDiZ5UWIv7ImX0MRsf615BnwxxHt/A0P1OPQ0MY01LC3sWAPwA="
        }
}

It is a cross shard transaction, its debt is:
{
        "Hash": "0x5ecc232012ae6a1cfe9ab88ca38583872c0bc0b2e1da4e987f5dc98cbde8c0f1",
        "Data": {
                "TxHash": "0x07d874cad8305bdcb813221425725d0c4ce651a20420e98cc0e911e181ae1da1",
                "From": "0x4c10f2cd2159bb432094e3be7e17904c2b4aeb21",
                "Nonce": 1,
                "Account": "0xd228e1dd02bdce9656b8e195a77e0da0b70daea1",
                "Amount": 100000,
                "Price": 10,
                "Code": ""
        }
}
  • Query the transaction result with the transaction Hash on shard 1.
client getreceipt --hash 0x07d874cad8305bdcb813221425725d0c4ce651a20420e98cc0e911e181ae1da1
{
        "contract": "0x",
        "failed": false,
        "poststate": "0x0000000000000000000000000000000000000000000000000000000000000000",
        "result": "0x",
        "totalFee": 0,
        "txhash": "0x07d874cad8305bdcb813221425725d0c4ce651a20420e98cc0e911e181ae1da1",
        "usedGas": 42000
}

The result of "failed": falserow indicates that the transaction was successful. If the transaction is not completed, you may see get error when call rpc leveldb: not found. You could use client gettxbyhash to query the transaction status.

3. Get debt

  • When over 120 blocks are confirmed in shard 1 after this transaction is recorded on chain. The corresponding debt will be sent to shard 2. You can check the pending debt on shard 2. If the
client getdebts --address 127.0.0.1:8028
[
        {
                "Data": {
                        "Account": "0xd228e1dd02bdce9656b8e195a77e0da0b70daea1",
                        "Amount": 100000,
                        "Code": "",
                        "From": "0x4c10f2cd2159bb432094e3be7e17904c2b4aeb21",
                        "Nonce": 1,
                        "Price": 10,
                        "TxHash": "0x07d874cad8305bdcb813221425725d0c4ce651a20420e98cc0e911e181ae1da1"
                },
                "Hash": "0x5ecc232012ae6a1cfe9ab88ca38583872c0bc0b2e1da4e987f5dc98cbde8c0f1"
        }
]
  • Later, the debt will be packed by a new block in shard 2.
client getdebtbyhash --hash 0x5ecc232012ae6a1cfe9ab88ca38583872c0bc0b2e1da4e987f5dc98cbde8c0f1 --address 127.0.0.1:8028
{
        "blockHash": "0x02276e91e7e69fa133c614057728379cb0587e1d750941799ed03a665d9377ad",
        "blockHeight": 478,
        "debt": {
                "Data": {
                        "Account": "0xd228e1dd02bdce9656b8e195a77e0da0b70daea1",
                        "Amount": 100000,
                        "Code": "",
                        "From": "0x4c10f2cd2159bb432094e3be7e17904c2b4aeb21",
                        "Nonce": 1,
                        "Price": 10,
                        "TxHash": "0x07d874cad8305bdcb813221425725d0c4ce651a20420e98cc0e911e181ae1da1"
                },
                "Hash": "0x5ecc232012ae6a1cfe9ab88ca38583872c0bc0b2e1da4e987f5dc98cbde8c0f1"
        },
        "debtIndex": 0,
        "status": "block"
}

client getblock --height 478 -f=true  --address 127.0.0.1:8028
{
        "debts": [
                {
                        "Data": {
                                "Account": "0xd228e1dd02bdce9656b8e195a77e0da0b70daea1",
                                "Amount": 100000,
                                "Code": "",
                                "From": "0x4c10f2cd2159bb432094e3be7e17904c2b4aeb21",
                                "Nonce": 1,
                                "Price": 10,
                                "TxHash": "0x07d874cad8305bdcb813221425725d0c4ce651a20420e98cc0e911e181ae1da1"
                        },
                        "Hash": "0x5ecc232012ae6a1cfe9ab88ca38583872c0bc0b2e1da4e987f5dc98cbde8c0f1"
                }
        ],
        "hash": "0x02276e91e7e69fa133c614057728379cb0587e1d750941799ed03a665d9377ad",
        "header": {
                "Consensus": 0,
                "CreateTimestamp": 1542770231,
                "Creator": "0x0ea2a45ab5a909c309439b0e004c61b7b2a3e831",
                "DebtHash": "0xace17fc0943681060586db3ee72302ed1fe439213f3f9db419fbf54a65afb431",
                "Difficulty": 100,
                "ExtraData": "",
                "Height": 478,
                "PreviousBlockHash": "0x0075f608519738e0f81853d8551ec7b88ebc442d5d560ca916fdddb57b326f35",
                "ReceiptHash": "0xaad5b991fd1c7486b2ae20d2cafc7a75e0330a11f065c5d20a8f402cd02c1f17",
                "StateHash": "0xbe46b414d95179e8b14414c5356d0cedce11cf66b5fbaf989c64a5df5f95a303",
                "TxDebtHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
                "TxHash": "0xc44264dfe45bb09b09df9fa17c7b1848319d644a9ae392923619a6520bf4ac0f",
                "Witness": "MTE3ODU2OTQ0MTA4ODQ1MDUzMjU="
        },
        "totalDifficulty": 47900,
        "transactions": [
                {
                        "accountNonce": 0,
                        "amount": 150000000,
                        "from": "0x0000000000000000000000000000000000000000",
                        "gasLimit": 0,
                        "gasPrice": 0,
                        "hash": "0x715a0ac01ea7cb04af94a722dce3167979017f719dbeb58590f365e89fcced2a",
                        "payload": "",
                        "to": "0x0ea2a45ab5a909c309439b0e004c61b7b2a3e831"
                }
        ],
        "txDebts": []
}
  • Confirm the shard 2 account balance.
client getbalance --account 0xd228e1dd02bdce9656b8e195a77e0da0b70daea1 --address 127.0.0.1:8028
{
        "Account": "0xd228e1dd02bdce9656b8e195a77e0da0b70daea1",
        "Balance": 100000
}