Deep Dive
What a Database Actually Does When It Says Committed
The commit returns before the data is on the platter, and the gap between the log write and the flush is where durability lives, and where one setting…
Deep Dive
The Checkpoint Storm That Spiked Latency Every Few Minutes
Latency was fine, then terrible, then fine, on a rhythm of a few minutes, with no traffic rhythm to match. The period was the checkpoint interval, and the…
Deep Dive
Why Adding One Server Moved Everyone's Cache
The cache was sharded by modulo, so the twelfth server rehashed every key, and the whole cluster went cold at once, and the database took the entire load in…
Deep Dive
Why AI-Written Code Is Shaped Like the Happy Path
Generated code reflects the distribution it was trained on, and that distribution is tutorials and working examples, so the edges are where generated code…
Deep Dive
What the Cache Headers Actually Mean, and Which One Wins
Four headers set the caching behaviour and they disagree, so the effective policy is a precedence order rather than a sum, and the order is not what the…
Shopify
A Performance Budget That Survives Contact With a Real Store
Performance work that is not enforced gets undone within a quarter. Here is the budget I use, the numbers behind each limit, and how to fail a build on it.
Shopify
How to Tell Which App Is Actually Slowing Your Store Down
Uninstalling apps one at a time and re-running Lighthouse is not a method. Here is how to attribute main thread time and bytes to a specific app in one pass.
Deep Dive
Readiness, Liveness and the Probe That Restarted a Healthy Pod
The pod was serving fine until Kubernetes killed it, repeatedly, because a liveness probe shared the event loop with the work.
Deep Dive
What an Agent Forgets When Its Context Gets Compacted
The agent worked well for the first hour, then started re reading files it had already read and re proposing fixes it had already rejected.
Deep Dive
Temperature Zero Is Not Deterministic
The repro failed because the model gave a different answer to the identical prompt, at temperature zero, twice. Determinism was never a property of the setting.
Deep Dive
Why an Index Only Scan Still Read the Heap
The plan said Index Only Scan, the buffers said the heap was read anyway, and the win never arrived. Index only is conditional on the visibility map, and…
Shopify
The Product With Eleven Options and Only One Hundred Variants
Three options with six values each is two hundred and sixteen combinations, and the platform's limit is one hundred variants.