Understanding Ethereum Node Behavior When the Transaction Pool Is Not Full
The Ethereum blockchain is designed to process transactions in a way that allows it to grow and scale without interruption. However, sometimes the transaction pool of Ethereum nodes, such as Geth or Erigon, is unable to accommodate all the new transactions within a block, resulting in partial blocks or even network congestion.
In this article, we will look at what happens when an Ethereum node’s transaction pool is not full, specifically when there are not enough transactions in the pool to fill a new creation block (i.e. a block containing one or more unconfirmed transactions).
What do Geth/Erigon do if the event pool is not full?
When an Ethereum node encounters a situation where the transaction pool is not large enough to fill a new block, it will attempt to:
- Add additional blocks: A node can create new blocks and add them to its queue of pending blocks until the transaction pool is full.
- Merge existing blocks with new transactions: If there are unconfirmed transactions in the pool that can be merged with existing blocks without creating new ones, the node will attempt to save space and avoid network congestion.
- Use the “partial block” mechanism: In some cases, if the transaction pool is too small to fill the entire block, a node can create a partially filled block (also known as a “partial block”). This means that even if not all transactions in a block are included, they will still appear in the blockchain.
Do nodes immediately create a partially filled block?
Not always. While some nodes may choose to create a partially filled block to avoid congestion and maintain network stability, others may not do so at all or use alternative methods. Here’s why:
- Limited optimization features: Geth/Erigon nodes have limited optimization features compared to other Ethereum clients such as Parity or Remix. They can only handle blocks with an average size of around 1-2 MB.
- Resource limitations: Nodes may be unable to create a partially filled block due to resource limitations such as insufficient memory or processing power.
- Network Conditions: Poor network conditions, such as high congestion or frequent rejection of transactions on the network, can cause nodes to prioritize other tasks over creating partial blocks.
Alternatives and Mitigations
Some Ethereum clients and operators use alternative strategies to mitigate the problem of the transaction pool not completely filling a block:
- Using Scheduling
: Nodes can be scheduled to create new blocks at specific times or intervals to maintain network stability.
- Implementing “Queue Prioritization”: Some nodes prioritize events based on their urgency or importance, ensuring that critical events are processed first.
- Using other blockchain protocols: Other blockchain protocols, such as Polkadot or Cosmos, may be better suited for certain use cases and can help mitigate the problem of the transaction pool not completely filling the block.
In short, when an Ethereum node encounters a situation where the transaction pool is not full, it tries to handle the situation in different ways. While nodes can create partially filled blocks or prioritize other tasks over creating partial blocks, these measures are not always effective and can lead to network congestion.