Tooling
A boring monorepo layout that has survived three years and 40 packages
Three top-level folders, one dependency rule and pnpm filters for CI. The monorepo structure we keep coming back to, and what we stopped doing.
9 stories
Latest posts
Null Pointer Press is a group engineering blog about Postgres, Node, Go, testing and reliability, written by four developers who run production.
Performance
How to read a flame graph without guessing
Width is time, height is call depth, colour means nothing. A practical guide to reading CPU flame graphs from Go's pprof, using a real regression we fixed.
Postgres
Renaming a column without downtime: expand, migrate, contract
ALTER TABLE ... RENAME COLUMN takes a millisecond and breaks every running pod. A step-by-step expand and contract rename in Postgres, with the trigger we use.
Testing
TIL: our trial countdown was wrong one day a year, and only in Europe
A date test that passed for months failed on a CI runner in Berlin. What we learned about DST, local midnight and testing code that reads the clock.
Tooling
Feature flags without a vendor: one table, one function, one rule
For most teams, feature flags are a Postgres table, a hashing function and a policy about expiry dates. Here is ours, and when we would pay for a product instead.
Node.js
40 MB an hour: the Node memory leak hiding behind setMaxListeners(0)
A postmortem of a slow leak in a Node ingest service: how two heap snapshots, one retainer chain and a silenced warning led us to the bug.