What Is Parallelization?

What Is Parallelization?

In the blockchain space, parallelization is a method for processing multiple transactions at the same time. It involves transaction-level parallelization, block-level parallelization, and smart contract parallelization. The benefits of parallelization include faster transaction processing, improved scalability, and reduced gas costs.


Addressing the scalability issues in blockchain networks requires efficient transaction processing. This article delves into the fundamentals of parallelization, its mechanisms, various common types, and its advantages.

What Is Parallelization?

Parallelization, or Parallel Transaction Execution, involves handling multiple tasks concurrently. This approach is linked to parallel computing, a computer science concept that enables the simultaneous execution of various processes.

How Parallelization Works

Parallelization enhances network efficiency by allowing multiple transactions to be validated simultaneously rather than sequentially. This method distributes transaction processing across multiple nodes, each handling different transaction segments, which speeds up processing and alleviates network congestion.

In this system, the network evaluates various potential states concurrently, each representing the impact of validating specific transaction groups. This enables the network to determine transaction effects before they are recorded on the ledger, with nodes agreeing on a unified state reflecting these parallel validations.

Parallelization Models

Parallelization in blockchain mainly comprises two models: optimistic parallelization and state-access parallelization.

  1. Optimistic Parallelization: This model bypasses initial sorting and processes transactions concurrently, assuming they are mostly independent. If interdependencies are discovered post-execution, the system adjusts to maintain data accuracy.
  2. State-Access Parallelization: This model categorizes transactions based on their impact on the network state, identifying those that can be processed in parallel. Independent transactions execute simultaneously, while those affecting similar state elements are processed in a prioritized order based on gas fees.

Types of Parallelization

Transaction-Level Parallelization

This method enables multiple transactions to be processed simultaneously, boosting the network's throughput and increasing transactions per second (TPS). It also shortens confirmation times, enhancing network responsiveness. Transaction-level parallelization is crucial for high-demand blockchains that require swift processing. However, it presents challenges such as managing data dependencies, where one transaction's output affects another, necessitating sophisticated data management strategies to maintain consistency and reliability.

Block-Level Parallelization

Block-level parallelization focuses on the concurrent creation and validation of blocks to enhance network scalability. By processing multiple blocks at once, it helps prevent network congestion and accommodates more transactions. However, this approach requires meticulous implementation to maintain blockchain security and demands higher computational resources, which could increase hardware requirements for network nodes. This might limit participation and impact the network's decentralization and accessibility.

Smart Contract Parallelization

This type involves executing multiple smart contracts in parallel, improving decentralized applications' (DApps) performance, scalability, and responsiveness. Mechanisms supporting this include optimistic rollups, which process transactions off-chain and only finalize them on the blockchain, and Ethereum's Validium, which combines zero-knowledge proofs with off-chain computation for scalability and privacy.

Advantages of Parallelization

  • Enhanced Transaction Processing Speed: Utilizing parallelization reduces transaction execution times by distributing tasks across multiple nodes, resulting in faster processing speeds compared to sequential models.
  • Improved Scalability: Parallelization addresses blockchain scalability challenges by distributing transaction validation across nodes, facilitating horizontal scaling. This enables the network to adjust node numbers based on demand fluctuations.
  • Lower Gas Costs: Parallelization lowers fees by assigning transactions to node subgroups, reducing costs compared to sequential processing. Additionally, faster transaction speeds mitigate competition between nodes, further decreasing transaction fees.


Parallelization involves processing multiple transactions concurrently, providing benefits like increased processing speeds, enhanced scalability, and reduced fees. Combining parallelization with other scaling solutions, such as sharding, holds promise for achieving further scalability in blockchain networks.

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