case n == 0:
		// TODO(bradfitz): ask driver, if supported, for its default preference
		return defaultMaxIdleConns
	case n < 0:
		return 0
	default:
		return n
	}
}

func (db *DB) shortestIdleTimeLocked() time.Duration {
	if db.maxIdleTime <= 0 {
		return db.maxLifetime
	}
	if db.maxLifetime <= 0 {
		return db.maxIdleTime
	}
	return min(db.maxIdleTime, db.maxLifetime)
}