Polygon, a layer 2 scaling solution on Ethereum, faced a brief but significant disruption on Wednesday as some of its nodes went out of sync, causing issues that affected performance and caused the popular blockchain explorer, PolygonScan, to go offline.
The incident prompted Polygon’s leader, Sandeep Nailwal, to tweet that there were “issues” with the blockchain explorer, which created confusion and speculation that there was a possible blockchain malfunction. However, a spokesperson for Polygon later confirmed that some nodes fell out of sync at approximately 8:26 UTC, which caused a reaction where some nodes could not validate blocks for a brief period.
Degraded Performance and Impact on Developers
As a result of the out-of-sync nodes, dapp developers who were reliant on impacted nodes struggled to get their services back online, according to Greg Lang, founder of node infrastructure company, Rivet. Although Lang hesitated to call the incident a catastrophe, he believed that more people were impacted than were talking about it.
The interruption caused a degradation in network performance, which was a temporary issue. A spokesperson for Polygon explained that when nodes fall behind, it creates a fork in the chain, leading to dueling accounts of the chain’s permanent record. A block reorganization is how the network resolves the discrepancy by excluding one of the records in favor of the correct, canonical record.
Unusually Large Block Reorganization
Lang stated that Polygon’s troubles appeared to stem from an unusually large block reorganization that occurred two minutes before Polygon said nodes went out of sync. A reorg is common on Ethereum and other networks based on the Ethereum Virtual Machine (EVM). Still, this one was different because it involved 157 blocks, which was outside the norm for Polygon reorganizations.
Infrastructure providers like Rivet handle reorgs differently, and Rivet can automatically handle shuffles of roughly 125 or less. However, beyond that, Rivet must manually restore the chain history from backups, which likely happened on Wednesday. Node operators can also get thrown off-kilter by blockchain reorganizations, which could even cause them to serve stale data (data from excluded blocks) if they don’t get back on track quickly.
Outage of Popular Block Explorer
The most notable outcome of Polygon’s period of instability was the outage of the popular block explorer, PolygonScan. According to the Polygon spokesperson, the network issues caused PolygonScan to get stuck because the block explorer utilizes nodes that had fallen out of sync. Nailwal suggested that the OKLink explorer was available as an alternative.
Investigation and Future Plans
All nodes have come back in sync, according to the Polygon spokesperson, who added that Polygon is investigating what caused the issue. Although there was no need for alarm, the incident highlights the potential risks associated with relying on decentralized networks.
In conclusion, while the brief disruption on Polygon caused some inconvenience, it highlights the importance of taking precautions when using decentralized networks. It is crucial to have backup plans and redundancies in place to minimize the impact of outages and disruptions. Nonetheless, Polygon’s prompt response to the issue and quick restoration of service indicates that it is a reliable and robust network.