Let's chat about performance, optimization, and debugging a PostgreSQL database. Can you read EXPLAIN ANALYZE output fluently? Do you know how to find which tenant is causing a slow query, how to use pg_stat_statements, how to spot lock contention? If you have a hard time answering those, don't worry. Today we're going to cover all of them and practice how to get better at it.
The goal here: you should be able to look at a slow API endpoint and trace it down to the exact query, the exact tenant, the exact missing index, in under 10 minutes. That's the bar.
EXPLAIN ANALYZE: read the plan, not the vibes
Let's start with EXPLAIN ANALYZE because everything else builds on it.
So why does this exist?
