Deep Dive
Node Event Loop Phases: Where Your setTimeout Really Runs
setTimeout zero and setImmediate are not the same thing, and which one runs first depends on where in the event loop you called them.
Latest
Bug Hunt
The Export That Always Returned Nine Hundred and Ninety Nine Rows
The finance team's export was short by a few rows and nobody knew by how many. The client library capped results at a thousand and raised no error, so the…
Error Autopsy
504 Gateway Timeout While Your Application Was Still Working
The proxy gave up at sixty seconds and returned a 504. The application finished at seventy four and wrote the result to nobody. Both were correct.
Shopify
New Customer Accounts Broke Every Template Override You Had
After switching on new customer accounts, the carefully styled login, order history and address pages vanished, replaced by defaults.
Security
The Rate Limit That Counted IPs and Not Accounts
The login rate limit was working perfectly and the credential stuffing succeeded completely. A per IP limiter is a defence against a single attacker, and a…
Performance
The Index That Made Inserts Four Times Slower
Every index is a second write. On an insert heavy table, nine well meaning indexes turned a fast append into a small transaction against ten data…
DevOps
The Helm Value You Set and the One That Actually Applied
You set the value in three places and the cluster applied a fourth. Helm's precedence rules are short and unforgiving, and the gap between what you edited…
Tooling
lsof and ss Will Tell You Who Owns That Port
Port in use, connection stuck, file handle exhausted. Three of the most common production questions are answered by two old tools that read the kernel's own…
Code Review
Reviewing a Migration on a 400 Million Row Table
A migration that is instant on a thousand row table can lock a production table for minutes at scale. Review for locking, backfill strategy and rollback…
Opinion
Most of Your Microservices Should Be Modules
A network call is a thousand times slower than a function call and a hundred times harder to debug. Most service boundaries were drawn for organisational…
Deep Dive
HTTP/2 Fixed Head of Line Blocking, Then Reintroduced It
HTTP/2 multiplexed many streams over one connection to escape head of line blocking, then moved the blocking one layer down into TCP, where a single lost…
Bug Hunt
The Cron Job That Ran Thirteen Times in One Night
A nightly job was supposed to run once. The logs showed thirteen executions in a few hours, then none for a day.