SQL Explain is your friend: PostgreSQL edition

- Identifying slow database queries with pg_stat_statements and EXPLAIN. - EXPLAIN provides insights into query execution plans, revealing potential performance bottlenecks. - Different forms of EXPLAIN provide varying levels of information: EXPLAIN, EXPLAIN ANALYZE, and EXPLAIN (ANALYZE, BUFFERS). - EXPLAIN output includes query execution plans, cost estimates, actual execution times, and buffer usage. - Indexes can significantly improve query performance by reducing sequential scans. - EXPLAIN can reveal unexpected query plans, highlighting the importance of testing assumptions. - EXPLAIN shows if ORM-generated queries are inefficient, e.g., selecting all columns when only a few are needed. - EXPLAIN helps validate query optimizations and understand database behavior. - Understanding execution plans with EXPLAIN is crucial for optimizing complex systems where subtle differences impact performance. - The combination of pg_stat_statements and EXPLAIN provides a comprehensive approach to identifying and addressing slow database queries.