Articles
Notes on backend architecture, performance work, and the WordPress and Laravel systems I build.
13 min readYour cron ran twice: why exactly-once scheduling does not exist
A job runs at midnight for four years, then runs twice with no deploy. The prime suspect is a daylight-saving fall-back, but there are eight others — clock steps, duplicate schedulers, catch-up controllers, lost acks. How to tell them apart from the logs in ten minutes, and why the real fix is a run key with a unique index rather than a better schedule.
Intermediate- Scheduling
- Reliability
- Distributed Systems
- Operations
15 min readMillions of rows nobody uses: how to delete them without breaking production
You found a table with millions of rows and no obvious owner. This is the playbook: prove nothing reads it, make every step reversible before any step is destructive, then delete in batches your replicas can survive — with the MySQL and PostgreSQL queries that produce the evidence.
Intermediate- Databases
- MySQL
- PostgreSQL
- Operations