Why Database Query Plan Caching Backfires at Scale

Episode 112 of Database Tech with Fexingo tackles a hidden performance killer: query plan caching. Lucas and Luna unpack why reusing cached plans can lead to catastrophic suboptimal execution as data distributions shift, using a real-world case from a mid-size e-commerce company that saw query latency spike 10x after a data ingestion update. They explain the difference between simple and parameterized plans, the role of statistics staleness, and why SQL Server's 'parameter sniffing' is both a feature and a footgun. The hosts discuss mitigation strategies like plan forcing, query hints, and adaptive query processing, and why some teams disable caching entirely for volatile workloads. By the end, listeners understand that caching isn't always a performance win — and when to invalidate it deliberately. #QueryPlanCaching #SQL #Performance #Database #ParameterSniffing #PlanCache #SQLServer #PostgreSQL #Statistics #Optimizer #Indexing #ExecutionPlan #Tech #DatabaseTechWithFexingo #FexingoBusiness #BusinessPodcast #SoftwareEngineering #DataEngineering Keep every episode free: buymeacoffee.com/fexingo