How to overcome the performance bottleneck of Blockchain through the Sharding mechanism

Core Insights Overview

• Sharding divides the blockchain network into multiple independently operating units, fundamentally alleviating the network congestion problem.
• Sharding can significantly enhance transaction confirmation speed and system throughput through parallel processing mechanisms.
• The security risks of cross-shard transactions and data consistency issues remain a challenge in the industry.

The “Triangle Dilemma” Facing Blockchain and Directions for Breakthroughs

The current blockchain technology is in an awkward situation: it is either highly decentralized but slow, or fast but sacrifices security. This is what the industry often refers to as the “trilemma”—it is difficult to meet all demands simultaneously among decentralization, security, and scalability.

Most first-layer public chains have suffered losses on this issue. Every validating node must record and process all transactions, and this “full synchronization” model leads to network performance becoming a bottleneck. The emergence of sharding technology provides a feasible idea to solve this problem.

The Technical Essence of Sharding: The Blockchain Application of the Database Divide-and-Conquer Concept

The concept of sharding did not arise out of thin air, but rather originates from sharding techniques in traditional database management. In the field of databases, sharding refers to the process of breaking a large dataset into smaller, manageable subsets.

After introducing this idea into blockchain, sharding becomes an architectural innovation: the entire blockchain network is divided into several relatively independent sub-chains (shards), each shard can independently verify and process transactions and smart contracts within its scope. This design significantly enhances transaction processing capability while maintaining the decentralized characteristics of the network.

How Sharding Changes Data Processing Logic

To understand the working mechanism of sharding, one must first clarify the essential differences in data processing between traditional blockchains and sharded blockchains.

Sequential Processing vs Parallel Processing

In traditional architecture, each validating node must process every transaction in the network sequentially. Imagine a highway with only one lane; no matter how many cars there are, they must line up. This “linear processing” model, while safe and reliable, severely restricts throughput.

Sharding technology breaks this limitation. It allows multiple shards to independently process their respective sets of transactions simultaneously, much like adding multiple parallel lanes on a highway. This parallel processing capability is the core value of sharding technology.

From “All Storage” to “On-Demand Storage”

The original design required each node to maintain a complete copy of the blockchain. As the amount of data increased, the hardware requirements for participating nodes also rose, ultimately leading to an exacerbation of network centralization—only organizations with sufficient capital could bear the costs.

Sharding has changed this pattern. Each node only needs to maintain the data of the shard it is in, rather than storing the complete history of the entire network. This means that ordinary users can become validators with regular hardware, achieving true decentralization.

Two Main Implementation Paths of Sharding

When expanding a database, the industry typically employs two types of partitioning methods—horizontal partitioning and vertical partitioning.

Horizontal Split: Split Data by Rows

Horizontal sharding refers to dividing data rows, with each shard containing a coherent subset of data. In blockchain applications, this is equivalent to grouping transactions based on account addresses or other identifiers, with different shards managing their respective sets of transactions.

Since each data row is independent, this method of splitting does not compromise the integrity of the data. Taking a network like Zilliqa as an example, it is precisely through horizontal partitioning that it achieves the processing capacity of thousands of transactions per second.

Vertical Split: Disperse Data by Column

Vertical partitioning divides according to different attributes (columns) of the data. For example, in an account table that includes fields like name, balance, transaction history, etc., vertical partitioning will distribute these fields across different storage units.

In a blockchain environment, vertical sharding applications are relatively limited because validating a transaction usually requires obtaining the complete information related to it, while vertical sharding increases the complexity of data retrieval.

Why Blockchain Tends to Prefer Horizontal Scaling

Compared to vertical partitioning, horizontal partitioning has advantages in blockchain in three aspects:

1. Scalability Advantages

Horizontal sharding allows each shard to operate and scale independently. New transactions only need to be assigned to the corresponding shard without involving the entire network. In this model, the system's capacity can theoretically grow linearly.

2. Maintenance of Decentralization

Horizontal sharding greatly reduces the computational and storage requirements of individual nodes. A regular computer is sufficient to run a shard node, allowing anyone to participate in the network, truly achieving democratization. Vertical sharding, on the other hand, requires each node to understand all dimensions of data, which raises the participation threshold.

3. Guarantee of Data Integrity

In horizontal partitioning, each shard saves the complete records of transactions within its range, allowing nodes to independently verify the authenticity of the data. The vertical partitioning's decentralized storage method, on the other hand, is prone to data fragmentation, making it more difficult to maintain data consistency.

Three Major Advantages of Sharding

A Quantum Leap in Trading Speed

In a sharded network, thousands of transactions can be executed simultaneously in different shards. Sharding projects like Zilliqa have demonstrated this potential—the network can confirm thousands of transactions in seconds. In contrast, traditional networks with single-thread processing show an order-of-magnitude speed difference.

Significant decrease in operational costs

Traditional models require each node to store complete data and perform all calculations. As the history of blockchain grows, this means that hardware investment continues to increase. Sharding changes this equation: nodes only process the data of their own shard, significantly reducing the required CPU, memory, and storage. The result is that more people can participate in network maintenance at a low cost, which is crucial for the long-term health of the blockchain.

Overall improvement of network efficiency

In traditional blockchains, the more nodes there are, the higher the cost of network synchronization. Sharding breaks this curse. Because newly added nodes can connect to any shard instead of the entire network, the system's throughput does not decrease with expansion; rather, it may be enhanced by the addition of more validators.

Real-World Challenges Faced by Sharding Technology

Despite the obvious advantages, sharding also introduces new technical challenges.

Risk of Single Shard Attack

The resources required to attack a shard are much less than those needed to attack the entire network. An attacker who controls 1% of the total computational power of the entire network may be sufficient to control a specific shard, thereby causing damage within that shard. This “shard attack” is a threat that must be taken seriously in shard design.

Complexity of Cross-Shard Transactions

What happens when two accounts are located in different shards? Cross-shard transfers not only involve the coordination of two shards but may also trigger “double spending” risks—if the state synchronization between shards is improper, an attacker may be able to reuse the same funds. Properly handling such edge cases is crucial for the maturity of the sharding solution.

Data Availability Issues

Suppose a certain shard suddenly becomes inaccessible due to a node going offline. This would cause the data of that shard to be temporarily unavailable, thereby affecting the stability of the entire network. In a decentralized network, ensuring that data remains accessible even in the case of partial node failures is a major design challenge.

Complexity of Load Balancing

If data distribution is uneven—such as when a popular smart contract happens to fall on a particular shard—that shard will become a performance bottleneck. Maintaining load balancing between shards requires precise algorithm design and continuous monitoring and adjustment.

Node Synchronization Delay

The network conditions of different nodes vary greatly. A bandwidth-constrained node can slow down the synchronization progress of the entire shard, thereby reducing overall network performance. This “barrel effect” is more pronounced in a sharded environment.

Sharding Plan in Ethereum 2.0

Ethereum has clearly identified sharding as an important goal in its upgrade roadmap. Ethereum 2.0 (also known as Eth2 or Serenity) is a system-level architectural overhaul aimed at significantly enhancing the network's transaction processing speed, energy efficiency, and scalability.

The official roadmap indicates that the complete sharding functionality will be launched in the final phase. Before that, the Ethereum community has conducted extensive validation work in the testing environment, striving to ensure that the system's security and decentralization characteristics are not compromised when it officially goes live.

The complexity of this work should not be underestimated. The development team needs to introduce sharding while maintaining consensus security, and also prevent various known and potential attack vectors. Current progress indicates that the industry has considerable confidence in the feasibility of sharding as a solution.

Looking to the Future

Sharding represents an important step towards the maturity of blockchain. It provides a competitive technical solution to break the “trilemma”, although there are still challenges to overcome, its potential is enormous.

More and more projects and infrastructures are seriously studying sharding. The official adoption by Ethereum, along with the practical validation by pioneers like Zilliqa, indicates that sharding has moved from theoretical discussion to practical application.

The key to the next step is continuous research investment, rigorous security audits, and comprehensive network testing. As technology matures and engineering experience accumulates, sharding is expected to become a standard feature of the next generation of blockchain systems.