Why Is My PostgreSQL Query Slow?

Common Reasons for Slow Queries

Slow PostgreSQL queries usually result from missing indexes, inefficient joins, large table scans, or poor configuration.

Check Execution Plan

EXPLAIN ANALYZE SELECT * FROM users;

This shows whether PostgreSQL performs a sequential scan instead of using an index.

Missing Indexes

If your WHERE clause filters on a column without an index, PostgreSQL scans the entire table.

Too Many JOINs

Complex joins increase planning and execution time. Simplify queries when possible.

Configuration Issues

Low work_mem or shared_buffers can limit performance.