presto-raptor-legacy/src/main/java/io/prestosql/plugin/raptor/legacy/storage/ShardRecoveryManager.java/ShardRecoveryManager/start
class ShardRecoveryManager:    @PostConstruct
    public void start()
    {
        if (!backupStore.isPresent()) {
            return;
        }
        if (started.compareAndSet(false, true)) {
            scheduleRecoverMissingShards();
        }
    }