Solana and Ethereum both use account-based models to manage states and assets on their blockchains, but they approach this structure differently. Here’s a breakdown of the key differences:
1. Account Structure:
- Ethereum:
- In Ethereum, an account holds both code (for smart contracts) and data (balance and storage).
- Each account can hold Ether (ETH) and interact directly with smart contracts.
- Accounts are either externally owned accounts (EOAs) or contract accounts.
- EOAs are controlled by private keys and can send and receive transactions, while contract accounts are controlled by code and respond to incoming transactions.
- Solana:
- Solana separates data storage from executable code using two distinct account types:
- Program accounts: Hold the executable code (like smart contracts).
- Data accounts: Hold data and can be accessed or modified by program accounts.
- A key difference is that program accounts are immutable after deployment, making them akin to static smart contracts, whereas data accounts can be dynamically updated.
- This separation enhances parallel processing in Solana, enabling high transaction throughput.
- Solana separates data storage from executable code using two distinct account types:
2. Account Ownership and Access Control:
- Ethereum:
- Accounts have a simpler structure where each account is individually controlled, either by a private key (for EOAs) or by code logic (for contract accounts).
- Each transaction can only access a limited number of accounts per execution, potentially causing bottlenecks with complex interactions.
- Solana:
- In Solana, each program account has a specific set of data accounts it can read or write to.
- To execute a transaction, Solana requires that all accounts to be accessed are specified upfront. This requirement optimizes Solana’s runtime to manage parallel transactions, enhancing speed and reducing contention.
- Solana also allows for custom permissions per account, enabling finer-grained access control compared to Ethereum.
3. Execution Model and Parallelization:
- Ethereum:
- Ethereum uses a single-threaded execution model, meaning only one transaction is processed at a time for each block.
- Ethereum’s state transition process is serialized, which can lead to bottlenecks, especially during high traffic periods.
- Solana:
- Solana’s runtime (the SeaLevel runtime) can handle multiple transactions in parallel if they access different accounts.
- By knowing which accounts will be accessed in each transaction, Solana avoids overlap and enables greater throughput.
- This architecture is key to Solana’s high-performance claims, allowing it to process tens of thousands of transactions per second (TPS) compared to Ethereum’s much lower TPS.
4. Cost Model and Rent Mechanism:
- Ethereum:
- Transaction fees are based on gas, which varies depending on the complexity of operations and network demand.
- Ethereum storage is theoretically permanent, with no mechanism for cleaning up unused storage.
- Solana:
- Solana requires accounts to pay rent based on their storage usage, incentivizing users to free up space and reduce blockchain bloat.
- If an account’s balance falls below a certain threshold, it may be removed (pruned), effectively “reclaiming” storage on the network.
- Solana’s fees are generally lower than Ethereum’s, given the network’s efficiency and design.
5. Account Addressing and Statefulness:
- Ethereum:
- Addresses are based on a user’s private key (EOAs) or are generated deterministically for contract accounts.
- Smart contracts maintain state within their storage and can be updated if allowed by the contract’s logic.
- Solana:
- Account addresses in Solana are not tied to user identities or private keys but are instead determined by program logic.
- Programs are stateless and focus only on logic execution, while data is kept in separate accounts, making Solana more modular.
- This setup helps streamline the execution and maintain a high throughput by minimizing redundant storage access.
Summary of Key Differences:
| Feature | Ethereum | Solana |
| Account Types | EOAs, Contract Accounts | Program Accounts, Data Accounts |
| Execution Model | Single-threaded | Multi-threaded (parallelizable) |
| Data Storage | In-account storage | Separate from executable accounts |
| Access Control | Private key or code logic | Program-specified access restrictions |
| Rent/Storage Model | No rent, permanent storage | Rent model with potential pruning |
| Transaction Cost | Gas fees based on operation complexity | Generally lower fees, rent-based cost |
These architectural differences allow Solana to achieve high throughput and lower costs but come with trade-offs in complexity and storage management compared to Ethereum’s simpler account-based model.