/**
   * @param rmtReducer Optional reducer.
   * @param rmtTransform Optional transformer.
   * @param args Arguments.
   * @return Future.
   */
  @SuppressWarnings("IfMayBeConditional")
  private <R> CacheQueryFuture<R> execute(
      @Nullable IgniteReducer<T, R> rmtReducer,
      @Nullable IgniteClosure<T, R> rmtTransform,
      @Nullable Object... args) {
    Collection<ClusterNode> nodes = nodes();

    cctx.checkSecurity(SecurityPermission.CACHE_READ);

    if (nodes.isEmpty())
      return new GridCacheQueryErrorFuture<>(
          cctx.kernalContext(), new ClusterGroupEmptyCheckedException());

    if (log.isDebugEnabled())
      log.debug("Executing query [query=" + this + ", nodes=" + nodes + ']');

    if (cctx.deploymentEnabled()) {
      try {
        cctx.deploy().registerClasses(filter, rmtReducer, rmtTransform);
        cctx.deploy().registerClasses(args);
      } catch (IgniteCheckedException e) {
        return new GridCacheQueryErrorFuture<>(cctx.kernalContext(), e);
      }
    }

    if (subjId == null) subjId = cctx.localNodeId();

    taskHash = cctx.kernalContext().job().currentTaskNameHash();

    final GridCacheQueryBean bean =
        new GridCacheQueryBean(
            this,
            (IgniteReducer<Object, Object>) rmtReducer,
            (IgniteClosure<Object, Object>) rmtTransform,
            args);

    final GridCacheQueryManager qryMgr = cctx.queries();

    boolean loc = nodes.size() == 1 && F.first(nodes).id().equals(cctx.localNodeId());

    if (type == SQL_FIELDS || type == SPI)
      return (CacheQueryFuture<R>)
          (loc ? qryMgr.queryFieldsLocal(bean) : qryMgr.queryFieldsDistributed(bean, nodes));
    else if (type == SCAN && part != null && nodes.size() > 1)
      return new CacheQueryFallbackFuture<>(nodes, bean, qryMgr);
    else
      return (CacheQueryFuture<R>)
          (loc ? qryMgr.queryLocal(bean) : qryMgr.queryDistributed(bean, nodes));
  }
  /**
   * @param rmtReducer Optional reducer.
   * @param rmtTransform Optional transformer.
   * @param args Arguments.
   * @return Future.
   */
  @SuppressWarnings("IfMayBeConditional")
  private <R> GridCacheQueryFuture<R> execute(
      @Nullable GridReducer<T, R> rmtReducer,
      @Nullable GridClosure<T, R> rmtTransform,
      @Nullable Object... args) {
    Collection<GridNode> nodes = nodes();

    cctx.checkSecurity(GridSecurityPermission.CACHE_READ);

    if (F.isEmpty(nodes))
      return new GridCacheQueryErrorFuture<>(
          cctx.kernalContext(),
          new GridEmptyProjectionException("There are no data nodes for cache: " + cctx.namexx()));

    if (log.isDebugEnabled())
      log.debug("Executing query [query=" + this + ", nodes=" + nodes + ']');

    if (cctx.deploymentEnabled()) {
      try {
        cctx.deploy().registerClasses(filter, rmtReducer, rmtTransform);
        cctx.deploy().registerClasses(args);
      } catch (GridException e) {
        return new GridCacheQueryErrorFuture<>(cctx.kernalContext(), e);
      }
    }

    if (subjId == null) subjId = cctx.localNodeId();

    taskHash = cctx.kernalContext().job().currentTaskNameHash();

    GridCacheQueryBean bean =
        new GridCacheQueryBean(
            this,
            (GridReducer<Object, Object>) rmtReducer,
            (GridClosure<Object, Object>) rmtTransform,
            args);

    GridCacheQueryManager qryMgr = cctx.queries();

    boolean loc = nodes.size() == 1 && F.first(nodes).id().equals(cctx.localNodeId());

    if (type == SQL_FIELDS)
      return (GridCacheQueryFuture<R>)
          (loc ? qryMgr.queryFieldsLocal(bean) : qryMgr.queryFieldsDistributed(bean, nodes));
    else
      return (GridCacheQueryFuture<R>)
          (loc ? qryMgr.queryLocal(bean) : qryMgr.queryDistributed(bean, nodes));
  }
  /** {@inheritDoc} */
  @Override
  public void start0() throws IgniteCheckedException {
    super.start0();

    assert cctx.config().getCacheMode() != LOCAL;

    cctx.io()
        .addHandler(
            cctx.cacheId(),
            GridCacheQueryRequest.class,
            new CI2<UUID, GridCacheQueryRequest>() {
              @Override
              public void apply(UUID nodeId, GridCacheQueryRequest req) {
                processQueryRequest(nodeId, req);
              }
            });

    lsnr =
        new GridLocalEventListener() {
          @Override
          public void onEvent(Event evt) {
            DiscoveryEvent discoEvt = (DiscoveryEvent) evt;

            for (GridCacheDistributedQueryFuture fut : futs.values())
              fut.onNodeLeft(discoEvt.eventNode().id());
          }
        };

    cctx.events().addListener(lsnr, EVT_NODE_LEFT, EVT_NODE_FAILED);
  }
  /** {@inheritDoc} */
  @Override
  public void printMemoryStats() {
    super.printMemoryStats();

    X.println(">>>   threadsSize: " + threads.size());
    X.println(">>>   futsSize: " + futs.size());
  }
  /** {@inheritDoc} */
  @Override
  void onCancelAtStop() {
    super.onCancelAtStop();

    for (GridCacheQueryFutureAdapter fut : futs.values())
      try {
        fut.cancel();
      } catch (IgniteCheckedException e) {
        U.error(log, "Failed to cancel running query future: " + fut, e);
      }

    U.interrupt(threads.values());
  }
    private void init() {
      ClusterNode node = nodes.poll();

      GridCacheQueryFutureAdapter<?, ?, R> fut0 =
          (GridCacheQueryFutureAdapter<?, ?, R>)
              (node.isLocal()
                  ? qryMgr.queryLocal(bean)
                  : qryMgr.queryDistributed(bean, Collections.singleton(node)));

      fut0.listen(
          new IgniteInClosure<IgniteInternalFuture<Collection<R>>>() {
            @Override
            public void apply(IgniteInternalFuture<Collection<R>> fut) {
              try {
                onDone(fut.get());
              } catch (IgniteCheckedException e) {
                if (F.isEmpty(nodes)) onDone(e);
                else init();
              }
            }
          });

      fut = fut0;
    }
  /** {@inheritDoc} */
  @Override
  void onWaitAtStop() {
    super.onWaitAtStop();

    // Wait till all requests will be finished.
    for (GridCacheQueryFutureAdapter fut : futs.values())
      try {
        fut.get();
      } catch (IgniteCheckedException e) {
        if (log.isDebugEnabled())
          log.debug(
              "Received query error while waiting for query to finish [queryFuture= "
                  + fut
                  + ", error= "
                  + e
                  + ']');
      }
  }
  /** {@inheritDoc} */
  @Override
  protected void onKernalStop0(boolean cancel) {
    super.onKernalStop0(cancel);

    cctx.events().removeListener(lsnr);
  }