Netflix AI Team Cuts Wide-Partition Read Latency from Seconds to Milliseconds by Splitting Cassandra Partitions Per ID

When databases store time-series data organized into partitions, those partitions can grow so large that reading from them takes seconds instead of milliseconds, causing system slowdowns. A team developed dynamic partitioning, which automatically splits oversized partitions into smaller ones without requiring application changes or downtime. The system detects wide partitions during reads, plans how to split them, and then routes future reads to the appropriate smaller partitions using Bloom filters and metadata lookups. This approach reduced read latency from seconds to low double-digit milliseconds while keeping large partitions available and maintaining data correctness through checksums and validation checks.