PostgreSQL Autovacuum 参数调优与监控实战

全局参数（postgresql.conf）： ``` autovacuum = on autovacuum_naptime = '10s' autovacuum_vacuum_threshold = 50 autovacuum_vacuum_scale_factor = 0.2 autovacuum_analyze_threshold = 50 autovacuum_analyze_scale_factor = 0.1 vacuum_cost_limit = 200 vacuum_cost_delay = '20ms' ``` 表级覆盖（高写入表）： ``` ALTER TABLE public.events SET ( autovacuum_vacuum_scale_factor = 0.05, autovacuum_analyze_scale_factor = 0.02, autovacuum_vacuum_threshold = 1000, autovacuum_analyze_threshold = 500 ); ``` 监控与人工维护： ``` SELECT relname, n_live_tup, n_dead_tup, last_vacuum, last_autovacuum, last_analyze, last_autoanalyze FROM pg_stat_all_tables WHERE schemaname = 'public' ORDER BY n_dead_tup DESC LIMIT 20; VACUUM (VERBOSE, ANALYZE) public.events; ```