Bug Hunt
The Race Condition That Vanished When I Added Logging
The classic heisenbug. Here is why observation changed the outcome, and the three techniques that found it anyway.
Bug Hunt
The Outage Caused by a Successful Health Check
Every replica restarted at once during a brief database blip. The health check was working exactly as designed, and the design was wrong.
Bug Hunt
A 400ms Latency Spike That Turned Out to Be DNS
p99 jumped on one service. The database was fine, every dependency reported healthy, and the flame graph pointed at nothing. That turned out to be the clue.
Bug Hunt
How a Timezone Bug Silently Corrupted Three Months of Analytics
The dashboard looked right. The numbers were wrong by a few percent every day, and the reason was one implicit conversion in a reporting query.
Shopify
The Shopify Cart Bug That Only Happens on Slow Connections
Items vanish from the cart, quantities are wrong, and it never reproduces on your machine. Throttle your network and it appears every time.
Bug Hunt
The Bug That Only Happened on Tuesdays
A weekly export failed every Tuesday and worked every other day. Three wrong hypotheses later, the cause was a date format string nobody had looked at in…
PostgreSQL
The Database Migration That Locked the Table for Nine Minutes
Adding a column should be instant. Sometimes it is not, and the difference is worth knowing before you run it in production.