MongoDB Tutorial 0/120 lessons ~6 min read Lesson 44
Query Optimization
Optimizing a slow query is a repeatable process: explain → identify scan → add index → re-explain.
Course progress0%
Focus
3 guided sections
Practice signal
Examples included
Career prep
Foundation builder
Introduction
Optimizing a slow query is a repeatable process: explain → identify scan → add index → re-explain. Done well, you turn 5-second queries into 5-millisecond ones.
Syntax reference
js
db.orders.find({ userId: 1 }).explain("executionStats");
Best practices
- Aim for
IXSCAN, neverCOLLSCANon hot paths. - Use compound indexes that cover filter + sort.
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