Rippling Engineering · 2024
Building Spend Management: Slashing latencies from 3.5s to 600ms
Author — then Engineering Manager, Spend Management
Auth p99: ~3.5s → 600ms. Indexes, planner hints, warmup, third-party I/O that doesn't block the rest of the request.
- 01
Indexes are left-to-right. Miss the leading field and you don't have an index.
- 02
The planner can be wrong 1% of the time. That 1% is your p99.
- 03
Hourly deploys plus just-in-time connections is a cold-start machine.
- 04
A timeout that blocks the rest of the request is only half a timeout.