Original Author: Haotian (X: @tmel0211)
A new narrative of “parallel EVM” has emerged in the market, which is very interesting in layer 2, which can realize a new paradigm of “refined” rollup, and the exaggeration can achieve the magic effect of Solana becoming the new layer 2 of Ethereum.
In my opinion, parallel EVM is just a manifestation of Rollup’s high degree of “modularity”, ** after DA was invaded by a third party, the VM execution layer fell again, and layer 2 will be redefined in the future. Next, let’s analyze from the perspective of popular science:
To understand this topic, we must first clarify the single-threaded execution model of the “EVM”.
This model stipulates that transactions must be processed and confirmed one after the other in order, which directly affects transaction processing speed, block time, and transaction throughput, which is the main reason for high EthereumMainnet gas and congestion. Moreover, the reason why it is designed to be single-threaded has certain historical limitations. **
Since transactions on Ethereum are verified and executed by distributed independent nodes, it is necessary to ensure that all address data, such as balances, smart contract code, etc., maintain the same state between different nodes, and at the same time ensure that there is no possibility of double spending of the same asset.
This allows transactions to be queued sequentially. If there are parallel transactions, it can lead to data synchronization errors between nodes, and the key is that there will be serious double-spend transactions.
Popular explanation: the bank has only one service window, customer withdrawals should be queued in order, whether it is deposit withdrawals and loans and other businesses, a customer can start the next one after completing the business, the advantage is that each operation of the bank’s account system will be accurately recorded, but the customer queuing time will be longer;
If the bank opens multiple service windows, customers can choose the window to handle different business, there will be two windows at the same time to try to deduct money from one account, if the account system reconciliation between the windows is not timely, it will lead to double spending, obviously this significantly improves efficiency, but the complex bookkeeping logic will bring pressure to the accounting system.
In the layer 1 independent chain scenario, if the underlying chain supports parallel processing, the problem will be solved, due to the separation of computing and storage state, Solana’s VM will Node sort these transactions after receiving multiple transactions from users, and then call independent storage system state data to detect whether these transactions have state conflicts, if there is no conflict, the transactions will be packaged into a Block, and if there is a conflict, the conflicting transactions will be excluded from this Block.
In contrast, Ethereum’s storage state is calculated in real time, and each transaction must wait for the previous transaction to complete before updating the state, so it is impossible to screen transactions before waiting for packaging, limiting the possibility of parallel processing. **
In the case of layer 2 rollup chains, to achieve parallel processing, it is similar to staying away. You can think of Solana’s transaction computation and storage state detection while waiting for POH Timestamps as the process by which the Rollup Chain processes transactions in Sequener and then batches them to the Mainnet.
Now that layer 2 Sequener will arrange transactions in chronological order before Batch transactions, and then batch them to the Mainnet in order, how can it be multi-threaded?
**1) Based on the AA account abstraction model, multiple transactions can be initiated at the same time from the account state, **For example, if two transfers are executed at the same time, the AA Smart Contract will give it a nonce, which needs to be executed sequentially, if one is Transfer, one is Approve, it can be processed in parallel more flexibly without nonce restrictions. In the AA account model, each account can customize the transaction processing logic to achieve high concurrency with nonce.
For example, when layer 2 transactions are submitted to Sequencer, Sequencer can quickly detect the transaction logic, and perform fine sorting and screening, for example, if the same account initiates two transfers, the latter one should be excluded and wait for the next batch, and if the same account initiates two operations of different natures, it can be done at the same time Batch into a block.
Sounds simple, but that’s not the case, just taking the Decentralized Finance scenario as an example, there are two major challenges for Sequencer to achieve fine-grained management of transactions:
**1) To analyze transaction data in real time and understand the smart contract call methods and parameters of incoming data, **Take Decentralized Finance common staking as an example, a staking operation involves Token transfer, state update, staking period, and potential reward calculation. If there are a large number of users incoming some staking transactions at the same time, if there are also transactions mixed with staking and then transferring, coupled with complex Oralce price factors, etc., if Sequener cannot parse and process it properly, a mistake may lead to serious accidents.
- Sequencer has to ensure Decentralization, the current layer 2 Sequener is only a Batch transaction under the premise that the rights are too large, if the Sequencer Decentralization problem cannot be solved, and then do a “fine-grained” Rollup, which is equivalent to giving Sequencer more permissions. If Sequencer makes fake transactions, blatantly engages in MEV clips, or even maliciously manipulates Oracle liquidation, etc., it will breed.
Recently, **Metis has been popular, ostensibly just Sequencer has achieved decentralization, and at a deeper level, it has built a basic consensus premise for Sequencer to do refined rollups in the future. **
Of course, relying on Sequencer to achieve highly refined rollup transaction aggregation and processing is still only an idea, ** fortunately, AA account abstraction, the overall modular combination of the Blockchain open mind provides a prerequisite for the implementation of this idea. **
Above.
Moreover, as mentioned above, layer 2 as a whole is becoming more and more modular, embedding ZK technology on the framework of the OP stack to achieve privacy extension, transforming the original Ethereum DA into a third-party DA such as Celestia to drop costs, gradually changing the tradition of ETH as a gas fee, giving layer 2 Token greater utility empowerment, and even layer 2 can batch transactions and submit them to different VM execution environments, and the transactions will be distributed Solana and Ethereum and more.
At that time, a new paradigm will emerge, and the current layer 2 is no longer just the layer 2 of Ethereum, Solana can also be the layer 2 of Ethereum, and even the definition of layer 2 will be magically changed.
** Bold assumption, now layer 2 has become an entry-level “layer 1” integrating high concurrent transaction processing capabilities, and Ethereum, Solana, these former layer 1s have become a new “layer 2” for asset settlement and security assurance. **
**Layer 2 has never been a rigid concept, and the mission of layer 2 platforms to solve large-scale concurrent transaction processing and attract incremental user market groups has always existed. **
If the mission is achieved, under the idea of modularity, not only the legitimacy of Ethereum layer 1 will be broken, but the entire whole chain of DA data availability, VM execution layer and even interoperability communication interaction will become the infra for layer 2 to achieve Mass Adoption.
At that time, Layer 2 will no longer be just a supplement to Layer 1, but will become a powerful and comprehensive transaction aggregation and distribution processing platform.
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