Comparison of Public Chain Technologies from the Perspective of Transaction Lifecycle

Comparing the technical characteristics of different public chains may seem obscure and difficult to understand due to varying perspectives. To quickly and accurately understand the differences between Aptos and other public chains, we can choose the transaction lifecycle as a starting point. By analyzing the complete steps of a transaction from creation to final state update, including creation and initiation, broadcasting, sorting, execution, and state update, we can clearly grasp the design philosophy and technical trade-offs of each public chain.

This article will focus on Aptos, analyzing its unique design and comparing key differences with Ethereum and Solana.

Aptos: Optimistic Concurrency and High-Performance Design

Aptos is a high-performance public chain that has a transaction lifecycle similar to Ethereum, but achieves significant performance improvements through unique optimistic parallel execution and memory pool optimization.

Create and Initiate

The Aptos network consists of light nodes, full nodes, and validators. Users initiate transactions through light nodes (such as wallets or applications), which forward the transactions to nearby full nodes, and the full nodes then synchronize with the validators.

Broadcast

Aptos retains the memory pool, but it is not shared between memory pools after QuorumStore. Unlike Ethereum, its memory pool is not just a transaction buffer. After a transaction enters the memory pool, the system pre-sorts it based on rules (such as FIFO or Gas fees) to ensure that there are no conflicts during subsequent parallel execution. This design avoids the high hardware requirements of having to declare read/write sets in advance.

sorting

Aptos adopts the AptosBFT consensus, where proposers cannot freely order transactions in principle. AIP-68 grants proposers the additional right to fill in delayed transactions. The pre-sorting of the memory pool has been completed in advance to avoid conflicts, and block generation relies more on the cooperation among validators rather than the leadership of proposers.

Execute

Aptos uses Block-STM technology to achieve optimistic parallel execution. Transactions are assumed to be conflict-free and processed simultaneously; if a conflict is detected after execution, the affected transactions will be re-executed. This method leverages multi-core processors to enhance efficiency, with a TPS of up to 160,000.

Status Update

Validator synchronization status is confirmed by finality through checkpoints, similar to Ethereum's Epoch mechanism, but with higher efficiency.

Aptos's core advantage lies in the combination of optimistic parallelism and pre-sorting in the memory pool, which reduces the performance demands on nodes while significantly increasing throughput.

Ethereum: Benchmark for Sequential Execution

As the pioneer of smart contracts, Ethereum is the origin of public chain technology, and its transaction lifecycle provides a foundational framework for understanding Aptos.

Ethereum transaction lifecycle

• Creation and Initiation: Users initiate transactions through wallets via relay gateways or RPC interfaces.
• Broadcasting: The transaction enters the public memory pool, waiting to be packaged.
• Sorting: After the PoS upgrade, block builders package transactions based on the principle of profit maximization, submit them to proposers after bidding on the relay layer.
• Execution: EVM processes transactions serially, updating the state in a single thread.
• Status Update: Blocks must be confirmed for finality through two checkpoints.

Ethereum's serial execution and memory pool design limit performance, with a block time of 12 seconds per slot and low TPS. In contrast, Aptos achieves a qualitative leap through parallel execution and memory pool optimization.

Solana: Ultimate Optimization of Deterministic Parallelism

Solana is known for its high performance, and its transaction lifecycle is significantly different from that of Aptos, especially in terms of the memory pool and execution methods.

Solana transaction lifecycle

• Create and Initiate: Users initiate transactions through their wallets.
• Broadcasting: No public memory pool, transactions are sent directly to the current and the next two proposers.
• Sorting: Proposers package blocks based on PoH (Proof of History), with block time of only 400 milliseconds.
• Execution: The Sealevel virtual machine uses deterministic parallel execution and requires prior declaration of read-write sets to avoid conflicts.
• Status Update: BFT consensus rapid confirmation.

The reason Solana does not use a memory pool is that it could become a performance bottleneck. Without a memory pool, and with Solana's unique PoH consensus, nodes can quickly reach consensus on the order of transactions, eliminating the need for transactions to queue in a memory pool, allowing transactions to be executed almost instantly. However, this also means that during network overload, transactions may be discarded rather than waiting, requiring users to resubmit.

In contrast, Aptos's optimistic concurrency does not require declaring read/write sets, has a lower node threshold, yet achieves a higher TPS.

Two Paths of Parallel Execution: Aptos vs Solana

The execution of a transaction represents the update of the blockchain state, which is the process of converting the transaction initiation instruction into a final state. Parallel execution refers to the process where multi-core processors compute the network state simultaneously. In the current market, parallel execution is divided into two methods: deterministic parallel execution and optimistic parallel execution.

• Deterministic Parallelism (Solana): A read-write set must be declared before broadcasting transactions, and the Sealevel engine processes non-conflicting transactions in parallel based on the declaration, while conflicting transactions are executed serially. The advantage is efficiency, while the disadvantage is high hardware requirements.

• Optimistic Concurrency (Aptos): Assumes transactions have no conflicts, Block-STM executes in parallel and then verifies. If there are conflicts, it retries. Pre-sorting in the memory pool reduces conflict risks, making the node's burden lighter.

Optimistic parallel processing to complete conflict confirmation in advance through the memory pool

Aptos's optimistic parallelism is not merely based on the assumption that transactions are conflict-free; rather, it preemptively mitigates risks during the transaction broadcasting phase. Once transactions enter the public memory pool, they are pre-sorted according to specific rules to ensure that transactions within a block do not conflict during parallel execution. This pre-sorting of transactions is key to Aptos's implementation of optimistic parallelism, significantly reducing the performance requirements on nodes while ensuring high TPS.

The narrative based on security is the development direction of Aptos.

RWA (Real World Assets)

Aptos's advantages in the RWA field:

• Block-STM processes multiple asset transfer transactions in parallel, avoiding delays in confirmation.
• Memory pool pre-sorting ensures transactions are executed in order, maintaining the reliability of asset records.
• Move language supports complex smart contracts, suitable for RWA application development.

Aptos's progress in RWA:

• In July 2024, USDY from Ondo Finance will be introduced.
• In October 2024, Franklin Templeton launched the BENJI token
• Collaborate with Libre to promote securities tokenization

stablecoin payment

Advantages of Aptos in the stablecoin payment sector:

• Move language resource model prevents double spending
• Low Gas fees are suitable for small payment scenarios
• Memory pool pre-sorting and Block-STM ensure the stability and low latency of payment transactions.
• AptosBFT consensus reduces centralization risk
• Modular architecture supports embedding KYC/AML checks

Possible future development directions for Aptos:

• Promote the large-scale adoption of stablecoins
• Build a cross-border payment network
• Develop on-chain settlement system
• Support micro-payment scenarios

Summary: The Technical Differences of Aptos and Future Narrative

Aptos integrates considerations of security and efficiency at every stage of the transaction lifecycle. Its memory pool pre-sorting combined with Block-STM's optimistic parallelism reduces the node threshold while achieving high throughput. Compared to Ethereum's robust inefficiency and Solana's high performance with high thresholds, Aptos strikes a clever balance between performance and security.

Aptos shows great potential in the RWA and PayFi fields. In terms of RWA, it has collaborated with multiple financial institutions to promote asset tokenization. In the PayFi and stablecoin payment sectors, its low cost, high efficiency, and compliance support a variety of application scenarios.

In the future, Aptos can leverage the narrative of "security-driven value networks" to connect traditional finance with the blockchain ecosystem, continuously making strides in the fields of RWA and PayFi, and building a new landscape for public chains that combines trust and scalability.