/**
   * @param key Removed key.
   * @param ver Removed version.
   * @throws IgniteCheckedException If failed.
   */
  public void onDeferredDelete(KeyCacheObject key, GridCacheVersion ver)
      throws IgniteCheckedException {
    try {
      T2<KeyCacheObject, GridCacheVersion> evicted = rmvQueue.add(new T2<>(key, ver));

      if (evicted != null) cctx.dht().removeVersionedEntry(evicted.get1(), evicted.get2());
    } catch (InterruptedException e) {
      Thread.currentThread().interrupt();

      throw new IgniteInterruptedCheckedException(e);
    }
  }
  /**
   * JUnit.
   *
   * @throws Exception If failed.
   */
  @SuppressWarnings({"TooBroadScope"})
  public void testRestarts() throws Exception {
    int duration = 60 * 1000;
    int qryThreadNum = 10;
    final long nodeLifeTime = 2 * 1000;
    final int logFreq = 20;

    final IgniteCache<Integer, Integer> cache = grid(0).cache(null);

    assert cache != null;

    for (int i = 0; i < KEY_CNT; i++) cache.put(i, i);

    assertEquals(KEY_CNT, cache.localSize());

    final AtomicInteger qryCnt = new AtomicInteger();

    final AtomicBoolean done = new AtomicBoolean();

    IgniteInternalFuture<?> fut1 =
        multithreadedAsync(
            new CAX() {
              @Override
              public void applyx() throws IgniteCheckedException {
                while (!done.get()) {
                  Collection<Cache.Entry<Integer, Integer>> res =
                      cache.query(new SqlQuery(Integer.class, "_val >= 0")).getAll();

                  assertFalse(res.isEmpty());

                  int c = qryCnt.incrementAndGet();

                  if (c % logFreq == 0) info("Executed queries: " + c);
                }
              }
            },
            qryThreadNum);

    final AtomicInteger restartCnt = new AtomicInteger();

    CollectingEventListener lsnr = new CollectingEventListener();

    for (int i = 0; i < GRID_CNT; i++)
      grid(i).events().localListen(lsnr, EventType.EVT_CACHE_REBALANCE_STOPPED);

    IgniteInternalFuture<?> fut2 =
        multithreadedAsync(
            new Callable<Object>() {
              @SuppressWarnings({"BusyWait"})
              @Override
              public Object call() throws Exception {
                while (!done.get()) {
                  int idx = GRID_CNT;

                  startGrid(idx);

                  Thread.sleep(nodeLifeTime);

                  stopGrid(idx);

                  int c = restartCnt.incrementAndGet();

                  if (c % logFreq == 0) info("Node restarts: " + c);
                }

                return true;
              }
            },
            1);

    Thread.sleep(duration);

    done.set(true);

    fut1.get();
    fut2.get();

    info("Awaiting rebalance events [restartCnt=" + restartCnt.get() + ']');

    boolean success = lsnr.awaitEvents(GRID_CNT * 2 * restartCnt.get(), 15000);

    for (int i = 0; i < GRID_CNT; i++)
      grid(i).events().stopLocalListen(lsnr, EventType.EVT_CACHE_REBALANCE_STOPPED);

    assert success;
  }