pg_stat_statements is a PostgreSQL core extension that tracks execution statistics for all SQL statements—providing essential performance monitoring without third-party tools. Available in all PostgreSQL installations (requires enabling in postgresql.conf). The extension captures query patterns (normalized with parameter placeholders), execution counts, total/mean/min/max execution times, rows affected, and block I/O statistics. Essential for identifying slow queries, frequently executed queries, and performance regressions. Statistics persist across server restarts when configured. Works with pg_stat_statements_reset() for baseline management. Commonly combined with visualization tools like pgBadger, pgHero, or Percona PMM for dashboards. The extension has minimal performance overhead (typically <5%) making it suitable for production use. Page should cover: installation and configuration, interpreting statistics columns, common analysis queries, combining with visualization tools, performance impact analysis, and comparison with external monitoring solutions.