What is parallelization in blockchain? It’s a huge leap forward, shifting from conventional sequential processing to a model where transactions occur concurrently and seamlessly. With the help of modern multi-core processors, parallelization significantly lowers transaction wait times and improves the network’s energy efficiency.

This offers a new age for blockchain applications with enhanced scalability and network performance.

What Is Parallelization in Blockchain?

Parallelization, or parallel execution, is the method of processing many tasks simultaneously. In blockchain, that refers to the simultaneous execution of transactions. In traditional sequential execution, transactions are processed one after another, while in parallelization, many transactions can be processed concurrently, improving the network’s scalability and performance.

The executions differentiate in the fundamental approach: in sequential execution, the entire network has to validate every transaction, resulting in increased effort for validators or miners and substantial energy consumption. Then again, parallelization maximizes the network’s abilities, lowering costs and improving transaction speeds while maintaining compatibility with parallelized EVM.

Models of Parallel Transaction Execution

  • Optimistic parallelization: The network skips the sorting stage and processes transactions simultaneously, assuming they are independent and returning to make adjustments if an execution is incorrect. In such cases, with additional dependencies related to the transactions, the transactions will be re-executed with the correct data.
  • State access parallelization: Transactions are first sorted, with the network grouping them based on their impact on the network’s state into, for example, related and unrelated transactions. The former include transactions interacting with the same account on the network or the same smart contract. The latter include unidirectional transactions interacting with different contracts. The network then executes unrelated transactions simultaneously, saving cost and time, whereas related transactions are re-coordinated before being processed.

Mechanics of Parallel Execution

Parallelization includes recognizing and eliminating independent transactions to execute them simultaneously, a key feature in modern parallel crypto networks. However, identifying such transactions is challenging, demanding a thorough understanding of how every transaction affects the blockchain’s recorded state or memory.

For example, transactions that interact with the same smart contract and alter its state cannot be processed simultaneously. Identifying these interdependencies is a challenging task due to the current interconnected nature of applications.

Each blockchain utilizes different parallelization crypto engines and methods for controlling transaction state access, similar to managing memory architecture in a computing system. Recognizing and managing interdependent transactions requires careful memory-handling protocols customized to each blockchain’s unique structure.

Advantages and Disadvantages of Parallel Execution

Advantages:

  • Scalability: When tasks are split and distributed across nodes, the network can process them faster and scale them horizontally. It can also contract more nodes during high-demand occasions, increasing the available resources and returning to normal after the demand decreases. This way, the network stays in shape when demand conditions fluctuate.
  • Transparency: Regardless of the processing speed, parallelization maintains the fundamental transparency trait of blockchain technology. In other words, transactions are accessible and open to all.
  • Lower gas costs: Parallelization allocates transactions to node subgroups and thus reduces gas fees. This is cheaper than sequential processing, where every node validates each transaction. Moreover, faster transaction speeds reduce node competition, decreasing transaction fees even more.

Disadvantages:

  • Decentralization: Parallelization needs a larger node network to leverage its benefits, which may compromise the blockchain system’s decentralized nature. The balance between quick transaction speeds and decentralization continues to be an important factor for blockchain developers and users.
  • Complexity: Due to the simultaneous execution of many transactions, nodes should quickly update information. This fast processing pace can impose a significant burden on the nodes.

Blockchains That Have Integrated Parallel Execution Into Their Systems

Let’s discuss the most popular parallel processing networks.

Solana

Anatoly Yakovenko, Solana’s co-founder, considers parallelization one of the eight features contributing to Solana’s high throughput. The blockchain’s parallel smart contract runtime, SeaLevel, uses all cores available to the validator and processes tens of thousands of contracts. Since each transaction gets validated very quickly, the process significantly reduces time.

The accounts feature and smart contracts structure enable Solana’s parallelization. Smart contracts on Solana are designed to specify the states they need to interact with. Every program declares the accounts it needs to interact with in advance, allowing transactions to be sorted based on state access. The virtual machine then schedules non-overlapping transactions to be executed simultaneously.

Aptos

According to Aptos, it runs transactions at 160,000 TPS, partly because of the organization of its parallel transaction execution system. It uses the optimistic model, which speeds things up, but errors may require a transaction to re-run.

Still, according to Aptos, its system automatically detects related transactions after the execution. Using the Block STM method, Aptos keeps track of each reaction’s changes and also tracks where the changes were made. When a related transaction ran in parallel produces an incorrect result, the result is wiped and repeated until correct results are obtained.

Sui

In addition to the state access parallelization model it uses, Sui introduces the concept of consensus bypass and objects. In Sui, smart contract transactions are linked to assets on the Sui blockchain known as reference objects. Every transaction is classified into complex and simple transactions.

The former needs extensive smart contract integrations and includes a shared object. They are sorted by how they affect the network’s states, where non-related transactions are executed simultaneously while related ones are executed in sequence. The latter involves regular transactions like asset transfers that don’t include a shared object. They are executed immediately without contacting the consensus system. By using this approach, Sui claims to achieve a transaction speed between 10,000 TPS and 290,000 TPS, depending on network conditions and demand.

Conclusion

So, what is parallelization in blockchain? Parallelization is the method of processing many tasks at the same time. In blockchain, that refers to the simultaneous execution of transactions. Parallelization includes recognizing and eliminating independent transactions to execute them simultaneously.

Scalability, transparency, and low gas costs are the most significant advantages of parallelization, while the complexity and the need for a larger node network, which compromises its decentralized nature, are some of the disadvantages. The most popular parallel processing networks are Solana, Aptos, and Sui.