Handle Reorgs

[willm30]

What is a reorg?

https://river.com/learn/terms/r/reorganization
https://cointelegraph.com/explained/what-is-chain-reorganization-in-blockchain-technology
https://www.alchemy.com/overviews/what-is-a-reorg

How to handle

Here are my notes from a call I had with Jakub, Raul and Alex:

when listening to blocks, for each block that comes in, we need to confirm that it's parent hash is the previous block we processed, else it's a reorg.

If it's a reorg, we need to go back the last block we saw that is consistent with the reorg, and re-sync from that block

We need to keep a list of the last 500 blocks we have processed, each block containing:

• block number
• block hash

-- We also need to think about undoing state changes in the db for blocks that got reorged (and which may, thus, no longer exist on chain)

Recommendations

Speak to Alex to remind yourself of the details before starting work on this.