Using VACUUM and ANALYZE

VACUUM (VERBOSE, ANALYZE) orders;

VACUUM;            -- whole DB
VACUUM ANALYZE;

VACUUM FULL orders;

VACUUM FREEZE orders;        -- preemptively freezes all visible tuples

VACUUM ANALYZE orders;       -- reclaim + update planner stats

ANALYZE orders;

ANALYZE orders (customer_id, placed_at);

autovacuum_max_workers          = 5
autovacuum_naptime              = 30s
autovacuum_vacuum_scale_factor  = 0.1
autovacuum_analyze_scale_factor = 0.05
autovacuum_vacuum_cost_limit    = 2000

-- Per-table override:
ALTER TABLE big_fact SET (autovacuum_vacuum_scale_factor = 0.02);

SELECT pid, datname, relid::regclass, phase, heap_blks_scanned, heap_blks_total
  FROM pg_stat_progress_vacuum;

SELECT relname, last_vacuum, last_autovacuum, last_analyze, last_autoanalyze
  FROM pg_stat_user_tables ORDER BY n_dead_tup DESC;

SELECT relname, n_live_tup, n_dead_tup,
       round(n_dead_tup::numeric / nullif(n_live_tup,0), 3) AS dead_ratio
  FROM pg_stat_user_tables ORDER BY n_dead_tup DESC;