Notes
Things that were not obvious until they broke.
- 25 Sept 2026Four bugs that only showed up under loadWhat load-testing a URL shortener to 37,893 requests per second found that no unit test would have.
- 25 Sept 2026Idempotency is a database constraint, not an if-statementWhy "check if it exists, then insert" loses the race it was written to prevent, and where the rule has to live instead.
- 25 Sept 2026The sync cursor could not be a timestampPaging message history across P2P nodes, and why the obvious cursor silently drops messages at page boundaries.