Postgres performance tuning best practices

Index coverage, VACUUM settings, and query plan analysis are the foundation of database optimization. Start by identifying slow queries with pg_stat_statements — it will show you exactly where your bottlenecks are rather than letting you guess based on symptoms. Once you have a list of target queries, use EXPLAIN (ANALYZE, BUFFERS) to understand how Postgres is actually executing them versus what you expect. Look for sequential scans on large tables, nested loops that should be hash joins, and index usage statistics — if an index has zero scans but high writes, it's just slowing down your inserts with no benefit. Autovacuum tuning is the most overlooked performance lever: default settings are often too conservative for write-heavy workloads, causing table bloat that degrades every query over time. For hot tables, consider aggressive autovacuum parameters like scale_factor = 0.05 and vacuum_cost_limit = 200 to