DHT Lookup Latency Performance
Dennis Trautwein
About this talk
This talk investigates the role of Hydra boosters in IPFS content routing using the DynamoDB backing store of Protocol Labs' production Hydra deployment, which spans roughly 2,000 heads across 135 instances and handles tens of thousands of RPCs per second. Dennis verifies that Hydras achieve about 97% coverage of the 20-closest-peer neighborhoods across the hash space, then joins provider and peer records to map CIDs to geographic locations, finding that around 55% of unique CIDs are provided from the United States, followed by the Netherlands, France, and Germany. The analysis surfaces a high CID churn rate of roughly 50% per day, that 85% of CIDs have only a single provider, and that the top ten providers account for over half of all CIDs in the network, with one peer alone providing 13%. Latency experiments comparing lookups with and without Hydras show only a marginal speedup and in some regions no improvement at all, suggesting the Hydras' contribution to DHT lookup performance is smaller than intended. The talk also reports on prefetching effectiveness and the dominance of the negative cache among prefetch outcomes.