The Shape‑First Tune‑Up Provides Organizations with a Means to Reduce MongoDB Expenses by 79%

TL;DR

A fast‑growing SaaS woke up to a silent auto‑scale from M20 → M60, adding 20 % to their cloud bill overnight. In a frantic 48‑hour sprint we:

• flattened N + 1 waterfalls with $lookup ,
• tamed unbounded cursors with projection, limit() and TTL,
• split 16 MB “jumbo” docs into lean metadata + GridFS blobs,
• reordered a handful of sleepy indexes

And watched $15 284 → $3 210/mo (‑79 %) while p95 latency toppled from 1.9 s → 140 ms.

All on a plain replica set.

Step 1: The Day the Invoice Went Supernova

02:17 a.m. — The on‑call phone lit up like a pinball machine. Atlas had quietly hot‑swapped our trusty M20 for a maxed‑out M60. Slack filled with Read More