PostgreSQL Query Optimization: 10 Techniques That Actually Work

PostgreSQL Query Optimization: 10 Techniques That Actually Work Most PostgreSQL performance advice is either too obvious ("add an index") or too abstract ("tune your queries"). Here are 10 specific techniques with real SQL examples, ordered by how much impact they typically have. Each one includes concrete before/after evidence so you can measure the improvement yourself. 1. Read EXPLAIN ANALYZE Output Properly Every optimization starts with understanding what the database is actually doing. Most people run EXPLAIN ANALYZE , glance at the total cost, and miss the real signals. Here is a query that looks simple but performs terribly: EXPLAIN ( ANALYZE , BUFFERS , FORMAT TEXT ) SELECT o . order_id , o . total_amount , c . customer_name FROM orders o JOIN customers c ON c . customer_id = o . customer_id WHERE o . status = 'pending' AND o . created_at > now () - interval '30 days' ; Nested Loop (cost=0.43..28456.12 rows=15 width=52) (actual time=0.089..342.671 rows=847 loops=1) -> Seq Scan