psql -d appdb -c "SELECT name, setting FROM pg_settings WHERE name LIKE 'autovacuum%';"

pg_settings holds every run-time parameter; filtering on autovacuum% reveals the tunables (threshold, scale factor, workers) and their current values. Autovacuum is the background process that reclaims dead rows automatically. Override per table with ALTER TABLE SET (autovacuum_vacuum_threshold = ...).