Reading EXPLAIN ANALYZE

The plan tells you what the database did and what it expected. A large gap between estimated and actual rows is usually the real problem.

What this lesson covers

• Read a plan from the innermost node outwards
• Spot sequential scans that should be index scans
• Compare estimated against actual row counts

This lesson sits in Query Performance, part of PostgreSQL for Developers. It assumes what came before it and leads directly into the next lesson in the module.