presto-jmx/src/main/java/io/prestosql/plugin/jmx/JmxPeriodicSampler.java/JmxPeriodicSampler/start
class JmxPeriodicSampler:    @PostConstruct
    public void start()
    {
        if (tableHandles.size() > 0) {
            lastDumpTimestamp = roundToPeriod(currentTimeMillis());
            schedule();
        }
    }