Gnosis Co-founder: Beacon Chain experiences seven block reorganizations, Vitalik overly optimistic about PoS

Ethereum technology company Gnosis co-founder Martin Köppelmann stated on the evening of the 25th that the Beacon Chain of the Proof of Stake (PoS) consensus layer, a key player in the Ethereum merge, experienced a seven-block reorganization re-org a few hours ago.

Martin Köppelmann believes that this indicates that the current node's attestation strategy should be reconsidered to become a more stable chain.

Martin Köppelmann also believes that this indicates that Paradigm's CTO Georgios Konstantopoulos and Ethereum co-founder Vitalik Buterin were overly optimistic when they discussed "the stability of reorganization with PoS compared to PoW." In the current Ethereum mainnet, a reorganization of up to 7 blocks has not been seen for many years.

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The Ethereum beacon chain experienced a 7-block deep reorg ~2.5h ago. This shows that the current attestation strategy of nodes should be reconsidered to hopefully result in a more stable chain! (proposals already exist) pic.twitter.com/BkQrKuUlw1

— Martin Köppelmann 🇺🇦 (@koeppelmann) May 25, 2022

What is Blockchain Reorganization?

In "Ethereum Reorgs After the Merge," Georgios and Vitalik describe: "Due to delays, short reorganizations always happen."

One can understand better through this example:

Miner A and Miner B may both find a valid block simultaneously, but due to how blocks propagate through the p2p network, one part of the network may see A's block first, while another part may see B's block first. If both blocks have the same difficulty, a tie occurs, and the Ethereum client or a random selection chooses which block becomes the valid block on the main chain, or chooses the block seen earlier.

Usually, when a third miner C builds a block on top of either A's block or B's block, it breaks the tie. However, there are still occasional 2-5 block reorganizations.

In summary, "A reorganization is an event in which a block that was part of the main chain is no longer part of the main chain because a competing block beat it." Through fork choice rules, decisions are made for multiple valid side chains on who becomes the main chain to achieve finality.

Using the example of blocks ordered by time in the image below: Continuing from 2a, both 3a and 3b, with 3b having a total difficulty greater than the main chain formed by 3a, a reorganization occurs. Subsequently, the noticed 2b is also following block 1, and the total difficulties of 1-2b-3c are all greater than the individual branches linked by 2a, resulting in another reorganization, selecting 1-2b-3c as the main chain.

Vitalik also mentions in this article that reorganizations beyond 2-5 times are almost always due to extreme network failures, client errors, or malicious attacks.

While reorganizations are not fatal errors, they do impact node costs, user experience, uncertainty in transaction history, and 51% attack resistance.

Martin Köppelmann expressed the hope that the Ethereum community can discuss together to address this issue. He believes that seven block reorganizations could have significant impacts, including DEX trades, oracle updates, liquidations, etc., which may lead to significant MEV miner extractable value due to reordering.

Vitalik Responds to Proposal from Two Years Ago

In response, Vitalik posted a solution he proposed two years ago, and he is very supportive of this discussion.

Ethereum core developer @preston_vanloon stated: "We suspect this is due to Proposer Boost fork choice not yet being fully rolled out across the network. This reorg is not an indication of a flaw in fork choice but rather a complex interplay of updates and outdated client software."