Code Review
Every Timeout Should Be Shorter Than the One Above It
A request chain is a ladder of deadlines, and when a lower rung is longer than the one above, the upper layer pays for work nobody will ever read.
Latest
Opinion
The People Who Designed It Should Be on the Pager
Escalation paths that route incidents away from senior engineers also route the feedback away from the people who can fix the design.
Deep Dive
Your Container Has Two CPUs and Is Using One Point Three
The container's CPU limit is two cores and its usage never exceeds one point three, yet requests slow down. CFS quota throttles in hundred millisecond…
Bug Hunt
One Cache Key, Two Customers, and a Very Bad Morning
Two accounts selling the same product slug saw each other's cached pricing. The key was built from the thing that was shared, and the thing that differed…
Error Autopsy
Postgres 40001: Why Retrying the Transaction Is Correct
ERROR 40001 looks like a crash and feels like a bug. It is neither. It is the serializable isolation level doing its job, and the only correct client…
Shopify
Two Discounts Stacked and the Merchant Ate the Margin
An automatic discount and a code were never meant to combine. They did, because combinability is a setting with a permissive default, and the margin on…
Security
SQL Injection Inside the ORM You Trusted
The codebase was fully parameterised except one helper that interpolated a column name into an orderBy. That single string was the injection, and the ORM…
Performance
Measuring TTFB When a CDN Is Answering for You
Your TTFB chart says forty milliseconds and your origin says four hundred. Both are true. The CDN is answering the measurements, so you are benchmarking the…
DevOps
Requests, Limits and the QoS Class That Decided Who Died
When a node runs short of memory, Kubernetes does not choose eviction victims at random. It uses the QoS class, which your requests and limits silently…
Tooling
journalctl Is a Database and You Are Using It Like a Text File
Grepping a wall of journal output loses the structure the journal already keeps. It is a queryable database of structured fields, and the queries take…
Code Review
Reviewing Shared State by Asking What Happens Under Contention
Locks and shared state look correct in the single threaded reading of a review and fail only under contention, which is exactly the condition review never…
Opinion
Nobody Looks at Your Dashboard Until Something Is Already Broken
Dashboards are built for demos and read during incidents, which is the one moment they cannot help. Monitoring that is only useful after the fact is…