Performance
The Screen That Made Forty Requests to Render Once
Each component fetched its own slice, so one page view became forty round trips, and the waterfall was the latency rather than any single slow call, and no…
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DevOps
The Migration That Locked the Table for Eleven Minutes
The column was added with a default that required a full table rewrite, so the table took an exclusive lock and every write queued behind it until the…
Tooling
The Flame Graph That Showed the Regex Inside the JSON Parser
The profiler turned a guess about the database into a wide bar in the serializer, and the bar was a regular expression running once per field on every row…
Code Review
Reviewing the Timeout That Was Longer Than the Caller's
The service waited ten seconds for its dependency while the caller gave up after five, so the work continued for an audience that had left, and the caller's…
Opinion
The Alert That Fires Every Day Is Not an Alert
The page has been acknowledged without action for six weeks, and the acknowledgement is the decision, and the decision is that nothing is wrong, and the…
Bug Hunt
The Enum Case Nobody Handled and the Compiler Did Not Catch
A new status was added to the model and the match statement had no default, so the new value fell through to the fallback branch, and the order was silently…
Ecommerce
The Refund That Went Out Twice for One Return
The support tool had no idempotency key and the operator clicked again after a slow response, so the customer was refunded twice, and the ledger showed one…
Security
The Debug Endpoint That Was Still Enabled in Production
The route was added for one investigation and guarded by a flag nobody set back, so it served the environment and the stack traces to anyone who guessed the…
Performance
The Client That Opened a New Connection for Every Request
The HTTP client was constructed inside the call, so the pool was thrown away each time and every request paid the handshake, and the latency was the setup…
DevOps
The Canary That Received All the Traffic
The weight was set on the route and not on the service, so the one-pod canary took the full load, and the errors were the capacity rather than the code, and…
Tooling
The lsof Output That Showed Who Was Holding the Port
The bind failed with the address already in use and nothing in the project was running, and the listing named a leftover process from the previous session…
Opinion
The Blameless Postmortem With a Name in It
The document said blameless and then described what one engineer did, and the description was the blame, and the label was the cover, and the cover was the…