How Cloudflare's D1 keeps query execution at the edge while a separate control plane manages millions of SQLite databases.
Hyperdrive, Cloudflare's distributed connection pooler for Workers, keeps warm database connections on its network and can cache common query results in the CDN cache. Taking its MySQL support from beta to GA meant finding bugs like utf8 being a 3-byte alias (fixed with utf8mb4) and COM_RESET_CONNECTION silently resetting the charset to the server default. The hardest was an empty-result bug seen by the highest-volume MySQL customer in about 0.001% of queries, only with caching on. Each Hyperdrive instance has a Client node next to the Worker and an Endpoint node near the database, and they share a cache when they run in the same data center. Because drivers like Node's mysql2 don't support CLIENT_DEPRECATE_EOF, the Client rewrites results into the Worker's capabilities, so the two nodes were caching different bytes for the same query and could read each other's entries. Caching one canonical encoding no matter which node stores it fixed the bug, and Client connection success reached 99.99%.
OpenAI's Habitat storage platform went from one shared Azure Cosmos DB container, to dedicated single-tenant containers that pushed capacity planning onto every product team, and back to a shared container by default once Azure added hot-key throttling, request-priority QoS and a new serverless mode where each physical partition scales to 10K RU/s and splits on RU usage. After failover and failback outages in late 2024, OpenAI and Azure now co-own testing and monitoring. Replicating small latency-critical datasets widely, a Valkey lookaside cache invalidated through the Cosmos DB change feed, and a Rust rewrite of the proxy cut global read p50 from about 120 ms to about 10 ms.
Titus, Netflix's Kubernetes-based container platform, launches millions of containers a week on tens of thousands of EC2 instances, packing many teams onto shared hosts. cgroups can't fence last-level cache, memory bandwidth or the global lock in HTB network shaping, so a small-packet flood from one container could starve its neighbors, and stateful streaming jobs like Flink would fall behind and need minutes to catch up. After ruling out microVMs (Firecracker, Kata), gVisor and moving teams to plain EC2, Netflix added an allowlisted single-tenant mode: the federation layer tags eligible tasks, the autoscaler launches the smallest instance that fits each one just in time, and anti-affinity, taints, no preemption and no repacking keep it alone on its host, all behind the same Titus API. Flink, streaming connectors and telemetry pipelines now report stable operation, and the shared fleet packs more densely because sensitive workloads no longer need anti-affinity spreading. The cost is slower launches, since every task waits for its own instance, and fixed host overhead that can take tens of percent of a small node.
Instagram Live ingest moved from Meta's in-house RUSH protocol to the open IETF Media over QUIC standard on iOS and Android. Edge endpoints translate MoQ frames into the RUSH format, so the backend did not change. Server-side routing let the experiment resize in minutes, the transport falls back to TCP when UDP is blocked, and the launch matched RUSH on quality and reliability.