This journal is generated by AI

Two Ways to Kill Serverless Cold Starts

Two platform teams attacked the same problem—the latency spike when a serverless function boots from zero—from opposite ends of the architecture.

  • Vercel’s Scale to One: How Fluid Solves Cold Starts rejects scale-to-zero outright: Fluid always keeps at least one function instance running, so the platform scales to one instead of zero.
  • Fluid also rethinks the one-instance-per-request model: each function instance serves many concurrent requests, so bursts of traffic no longer translate into bursts of cold boots.
  • Cloudflare’s Eliminating Cold Starts 2: Shard and Conquer builds on their earlier trick of pre-warming a Worker during the TLS handshake of its first request—the handshake round-trips buy enough time to load the isolate before the actual HTTP request arrives.

Speed Over Consistency: Data Stores at Netflix and Discord

Two classic production write-ups showed how large services deliberately trade strict consistency for speed and availability, then engineer around the sharp edges.

  • Netflix’s Ephemeral Volatile Caching in the Cloud describes EVCache as a best-effort cache: the architecture chooses speed over consistency, and every dependent application must tolerate stale data.
  • The EVCache client is AWS zone-aware: writes and deletes replicate to the EVCache servers in every zone, while reads stay in the client’s own zone for latency. The Java client, built on spymemcached, handles discovery and cluster membership changes automatically.
  • Discord’s How Discord Stores Billions of Messages picked Cassandra because nodes can be added linearly and lost without impact—and captures a culture principle worth stealing: build quickly to prove out a feature, but always with a path to a more robust solution.
  • The best mental model for Cassandra is a KKV store: the partition key locates the node and disk position, the clustering key sorts rows within the partition—a partition is an ordered dictionary.
  • Two production gotchas stood out: writing null to a column generates a tombstone just like a delete (their 16-column schema averaged 4 set values, so most writes created 12 pointless tombstones—fixed by writing only non-null values), and queries over empty time buckets had to be tracked and skipped to avoid full scans on quiet channels.

Grit: Optimism, Parenting, and the Effort–Reward Connection

Continued through the later chapters of Angela Duckworth’s Grit, which move from the psychology of hope to how grit is grown in others.

  • The lesson on setbacks: don’t overreact—step back, analyze, and learn from them, but stay optimistic. Explaining adversity as permanent and pervasive turns minor complications into catastrophes; the seminal learned-helplessness experiments showed it isn’t suffering that leads to hopelessness, but suffering you think you can’t control.
  • What didn’t kill the young rats—when they could control what was happening by their own efforts—made them stronger for life. Direct experience of the connection between effort and reward matters: without it, animals and people alike default to laziness.
  • On parenting for grit: wise parents are child-centered without believing children are always the best judge of how hard to work or when to quit, and their authority rests on knowledge and wisdom rather than power.
  • The uncomfortable mirror: if you want a gritty child, first ask how much passion and perseverance you have for your own goals, and whether your parenting invites the child to emulate you.
  • The best coaching engineers situations slightly outside the comfort zone—far enough to stretch, close enough to reach.