/**
   * @param cctx Context.
   * @param id Partition ID.
   */
  @SuppressWarnings("ExternalizableWithoutPublicNoArgConstructor")
  GridDhtLocalPartition(GridCacheContext cctx, int id) {
    assert cctx != null;

    this.id = id;
    this.cctx = cctx;

    log = U.logger(cctx.kernalContext(), logRef, this);

    rent =
        new GridFutureAdapter<Object>() {
          @Override
          public String toString() {
            return "PartitionRentFuture [part=" + GridDhtLocalPartition.this + ", map=" + map + ']';
          }
        };

    map = new ConcurrentHashMap8<>(cctx.config().getStartSize() / cctx.affinity().partitions());

    int delQueueSize =
        CU.isSystemCache(cctx.name())
            ? 100
            : Math.max(MAX_DELETE_QUEUE_SIZE / cctx.affinity().partitions(), 20);

    rmvQueue = new GridCircularBuffer<>(U.ceilPow2(delQueueSize));
  }
  /** Clears swap entries for evicted partition. */
  private void clearSwap() {
    assert state() == EVICTED;
    assert !GridQueryProcessor.isEnabled(cctx.config())
        : "Indexing needs to have unswapped values.";

    try {
      GridCloseableIterator<Map.Entry<byte[], GridCacheSwapEntry>> it = cctx.swap().iterator(id);

      boolean isLocStore = cctx.store().isLocal();

      if (it != null) {
        // We can safely remove these values because no entries will be created for evicted
        // partition.
        while (it.hasNext()) {
          Map.Entry<byte[], GridCacheSwapEntry> entry = it.next();

          byte[] keyBytes = entry.getKey();

          KeyCacheObject key = cctx.toCacheKeyObject(keyBytes);

          cctx.swap().remove(key);

          if (isLocStore) cctx.store().remove(null, key.value(cctx.cacheObjectContext(), false));
        }
      }
    } catch (IgniteCheckedException e) {
      U.error(log, "Failed to clear swap for evicted partition: " + this, e);
    }
  }
 /** {@inheritDoc} */
 @Override
 public String toString() {
   return S.toString(
       GridDhtLocalPartition.class,
       this,
       "state",
       state(),
       "reservations",
       reservations(),
       "empty",
       map.isEmpty(),
       "createTime",
       U.format(createTime),
       "mapPubSize",
       mapPubSize);
 }
  /** Clears values for this partition. */
  private void clearAll() {
    GridCacheVersion clearVer = cctx.versions().next();

    boolean swap = cctx.isSwapOrOffheapEnabled();

    boolean rec = cctx.events().isRecordable(EVT_CACHE_REBALANCE_OBJECT_UNLOADED);

    Iterator<GridDhtCacheEntry> it = map.values().iterator();

    GridCloseableIterator<Map.Entry<byte[], GridCacheSwapEntry>> swapIt = null;

    if (swap
        && GridQueryProcessor.isEnabled(cctx.config())) { // Indexing needs to unswap cache values.
      Iterator<GridDhtCacheEntry> unswapIt = null;

      try {
        swapIt = cctx.swap().iterator(id);
        unswapIt = unswapIterator(swapIt);
      } catch (Exception e) {
        U.error(log, "Failed to clear swap for evicted partition: " + this, e);
      }

      if (unswapIt != null) it = F.concat(it, unswapIt);
    }

    try {
      while (it.hasNext()) {
        GridDhtCacheEntry cached = it.next();

        try {
          if (cached.clearInternal(clearVer, swap)) {
            map.remove(cached.key(), cached);

            if (!cached.isInternal()) {
              mapPubSize.decrement();

              if (rec)
                cctx.events()
                    .addEvent(
                        cached.partition(),
                        cached.key(),
                        cctx.localNodeId(),
                        (IgniteUuid) null,
                        null,
                        EVT_CACHE_REBALANCE_OBJECT_UNLOADED,
                        null,
                        false,
                        cached.rawGet(),
                        cached.hasValue(),
                        null,
                        null,
                        null);
            }
          }
        } catch (IgniteCheckedException e) {
          U.error(log, "Failed to clear cache entry for evicted partition: " + cached, e);
        }
      }
    } finally {
      U.close(swapIt, log);
    }
  }
/** Key partition. */
public class GridDhtLocalPartition implements Comparable<GridDhtLocalPartition>, GridReservable {
  /** Maximum size for delete queue. */
  public static final int MAX_DELETE_QUEUE_SIZE =
      Integer.getInteger(IGNITE_ATOMIC_CACHE_DELETE_HISTORY_SIZE, 200_000);

  /** Static logger to avoid re-creation. */
  private static final AtomicReference<IgniteLogger> logRef = new AtomicReference<>();

  /** Logger. */
  private static volatile IgniteLogger log;

  /** Partition ID. */
  private final int id;

  /** State. */
  @GridToStringExclude
  private final AtomicStampedReference<GridDhtPartitionState> state =
      new AtomicStampedReference<>(MOVING, 0);

  /** Rent future. */
  @GridToStringExclude private final GridFutureAdapter<?> rent;

  /** Entries map. */
  private final ConcurrentMap<KeyCacheObject, GridDhtCacheEntry> map;

  /** Context. */
  private final GridCacheContext cctx;

  /** Create time. */
  @GridToStringExclude private final long createTime = U.currentTimeMillis();

  /** Eviction history. */
  private volatile Map<KeyCacheObject, GridCacheVersion> evictHist = new HashMap<>();

  /** Lock. */
  private final ReentrantLock lock = new ReentrantLock();

  /** Public size counter. */
  private final LongAdder8 mapPubSize = new LongAdder8();

  /** Remove queue. */
  private final GridCircularBuffer<T2<KeyCacheObject, GridCacheVersion>> rmvQueue;

  /** Group reservations. */
  private final CopyOnWriteArrayList<GridDhtPartitionsReservation> reservations =
      new CopyOnWriteArrayList<>();

  /**
   * @param cctx Context.
   * @param id Partition ID.
   */
  @SuppressWarnings("ExternalizableWithoutPublicNoArgConstructor")
  GridDhtLocalPartition(GridCacheContext cctx, int id) {
    assert cctx != null;

    this.id = id;
    this.cctx = cctx;

    log = U.logger(cctx.kernalContext(), logRef, this);

    rent =
        new GridFutureAdapter<Object>() {
          @Override
          public String toString() {
            return "PartitionRentFuture [part=" + GridDhtLocalPartition.this + ", map=" + map + ']';
          }
        };

    map = new ConcurrentHashMap8<>(cctx.config().getStartSize() / cctx.affinity().partitions());

    int delQueueSize =
        CU.isSystemCache(cctx.name())
            ? 100
            : Math.max(MAX_DELETE_QUEUE_SIZE / cctx.affinity().partitions(), 20);

    rmvQueue = new GridCircularBuffer<>(U.ceilPow2(delQueueSize));
  }

  /**
   * Adds group reservation to this partition.
   *
   * @param r Reservation.
   * @return {@code false} If such reservation already added.
   */
  public boolean addReservation(GridDhtPartitionsReservation r) {
    assert state.getReference() != EVICTED : "we can reserve only active partitions";
    assert state.getStamp() != 0
        : "partition must be already reserved before adding group reservation";

    return reservations.addIfAbsent(r);
  }

  /** @param r Reservation. */
  public void removeReservation(GridDhtPartitionsReservation r) {
    if (!reservations.remove(r))
      throw new IllegalStateException("Reservation was already removed.");
  }

  /** @return Partition ID. */
  public int id() {
    return id;
  }

  /** @return Create time. */
  long createTime() {
    return createTime;
  }

  /** @return Partition state. */
  public GridDhtPartitionState state() {
    return state.getReference();
  }

  /** @return Reservations. */
  public int reservations() {
    return state.getStamp();
  }

  /** @return Keys belonging to partition. */
  public Set<KeyCacheObject> keySet() {
    return map.keySet();
  }

  /** @return Entries belonging to partition. */
  public Collection<GridDhtCacheEntry> entries() {
    return map.values();
  }

  /** @return {@code True} if partition is empty. */
  public boolean isEmpty() {
    return map.isEmpty();
  }

  /** @return Number of entries in this partition (constant-time method). */
  public int size() {
    return map.size();
  }

  /** Increments public size of the map. */
  public void incrementPublicSize() {
    mapPubSize.increment();
  }

  /** Decrements public size of the map. */
  public void decrementPublicSize() {
    mapPubSize.decrement();
  }

  /** @return Number of public (non-internal) entries in this partition. */
  public int publicSize() {
    return mapPubSize.intValue();
  }

  /** @return If partition is moving or owning or renting. */
  public boolean valid() {
    GridDhtPartitionState state = state();

    return state == MOVING || state == OWNING || state == RENTING;
  }

  /** @param entry Entry to add. */
  void onAdded(GridDhtCacheEntry entry) {
    GridDhtPartitionState state = state();

    if (state == EVICTED)
      throw new GridDhtInvalidPartitionException(
          id, "Adding entry to invalid partition [part=" + id + ']');

    map.put(entry.key(), entry);

    if (!entry.isInternal()) mapPubSize.increment();
  }

  /** @param entry Entry to remove. */
  @SuppressWarnings("SynchronizationOnLocalVariableOrMethodParameter")
  void onRemoved(GridDhtCacheEntry entry) {
    assert entry.obsolete();

    // Make sure to remove exactly this entry.
    synchronized (entry) {
      map.remove(entry.key(), entry);

      if (!entry.isInternal() && !entry.deleted()) mapPubSize.decrement();
    }

    // Attempt to evict.
    tryEvict(true);
  }

  /**
   * @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);
    }
  }

  /** Locks partition. */
  @SuppressWarnings({"LockAcquiredButNotSafelyReleased"})
  public void lock() {
    lock.lock();
  }

  /** Unlocks partition. */
  public void unlock() {
    lock.unlock();
  }

  /**
   * @param key Key.
   * @param ver Version.
   */
  public void onEntryEvicted(KeyCacheObject key, GridCacheVersion ver) {
    assert key != null;
    assert ver != null;
    assert lock.isHeldByCurrentThread(); // Only one thread can enter this method at a time.

    if (state() != MOVING) return;

    Map<KeyCacheObject, GridCacheVersion> evictHist0 = evictHist;

    if (evictHist0 != null) {
      GridCacheVersion ver0 = evictHist0.get(key);

      if (ver0 == null || ver0.isLess(ver)) {
        GridCacheVersion ver1 = evictHist0.put(key, ver);

        assert ver1 == ver0;
      }
    }
  }

  /**
   * Cache preloader should call this method within partition lock.
   *
   * @param key Key.
   * @param ver Version.
   * @return {@code True} if preloading is permitted.
   */
  public boolean preloadingPermitted(KeyCacheObject key, GridCacheVersion ver) {
    assert key != null;
    assert ver != null;
    assert lock.isHeldByCurrentThread(); // Only one thread can enter this method at a time.

    if (state() != MOVING) return false;

    Map<KeyCacheObject, GridCacheVersion> evictHist0 = evictHist;

    if (evictHist0 != null) {
      GridCacheVersion ver0 = evictHist0.get(key);

      // Permit preloading if version in history
      // is missing or less than passed in.
      return ver0 == null || ver0.isLess(ver);
    }

    return false;
  }

  /**
   * Reserves a partition so it won't be cleared.
   *
   * @return {@code True} if reserved.
   */
  @Override
  public boolean reserve() {
    while (true) {
      int reservations = state.getStamp();

      GridDhtPartitionState s = state.getReference();

      if (s == EVICTED) return false;

      if (state.compareAndSet(s, s, reservations, reservations + 1)) return true;
    }
  }

  /** Releases previously reserved partition. */
  @Override
  public void release() {
    while (true) {
      int reservations = state.getStamp();

      if (reservations == 0) return;

      GridDhtPartitionState s = state.getReference();

      assert s != EVICTED;

      // Decrement reservations.
      if (state.compareAndSet(s, s, reservations, --reservations)) {
        tryEvict(true);

        break;
      }
    }
  }

  /** @return {@code True} if transitioned to OWNING state. */
  boolean own() {
    while (true) {
      int reservations = state.getStamp();

      GridDhtPartitionState s = state.getReference();

      if (s == RENTING || s == EVICTED) return false;

      if (s == OWNING) return true;

      assert s == MOVING;

      if (state.compareAndSet(MOVING, OWNING, reservations, reservations)) {
        if (log.isDebugEnabled()) log.debug("Owned partition: " + this);

        // No need to keep history any more.
        evictHist = null;

        return true;
      }
    }
  }

  /**
   * @param updateSeq Update sequence.
   * @return Future to signal that this node is no longer an owner or backup.
   */
  IgniteInternalFuture<?> rent(boolean updateSeq) {
    while (true) {
      int reservations = state.getStamp();

      GridDhtPartitionState s = state.getReference();

      if (s == RENTING || s == EVICTED) return rent;

      if (state.compareAndSet(s, RENTING, reservations, reservations)) {
        if (log.isDebugEnabled()) log.debug("Moved partition to RENTING state: " + this);

        // Evict asynchronously, as the 'rent' method may be called
        // from within write locks on local partition.
        tryEvictAsync(updateSeq);

        break;
      }
    }

    return rent;
  }

  /**
   * @param updateSeq Update sequence.
   * @return Future for evict attempt.
   */
  IgniteInternalFuture<Boolean> tryEvictAsync(boolean updateSeq) {
    if (map.isEmpty()
        && !GridQueryProcessor.isEnabled(cctx.config())
        && state.compareAndSet(RENTING, EVICTED, 0, 0)) {
      if (log.isDebugEnabled()) log.debug("Evicted partition: " + this);

      clearSwap();

      if (cctx.isDrEnabled()) cctx.dr().partitionEvicted(id);

      cctx.dataStructures().onPartitionEvicted(id);

      rent.onDone();

      ((GridDhtPreloader) cctx.preloader()).onPartitionEvicted(this, updateSeq);

      clearDeferredDeletes();

      return new GridFinishedFuture<>(true);
    }

    return cctx.closures()
        .callLocalSafe(
            new GPC<Boolean>() {
              @Override
              public Boolean call() {
                return tryEvict(true);
              }
            }, /*system pool*/
            true);
  }

  /** @return {@code true} If there is a group reservation. */
  private boolean groupReserved() {
    for (GridDhtPartitionsReservation reservation : reservations) {
      if (!reservation.invalidate())
        return true; // Failed to invalidate reservation -> we are reserved.
    }

    return false;
  }

  /**
   * @param updateSeq Update sequence.
   * @return {@code True} if entry has been transitioned to state EVICTED.
   */
  boolean tryEvict(boolean updateSeq) {
    if (state.getReference() != RENTING || state.getStamp() != 0 || groupReserved()) return false;

    // Attempt to evict partition entries from cache.
    clearAll();

    if (map.isEmpty() && state.compareAndSet(RENTING, EVICTED, 0, 0)) {
      if (log.isDebugEnabled()) log.debug("Evicted partition: " + this);

      if (!GridQueryProcessor.isEnabled(cctx.config())) clearSwap();

      if (cctx.isDrEnabled()) cctx.dr().partitionEvicted(id);

      cctx.dataStructures().onPartitionEvicted(id);

      rent.onDone();

      ((GridDhtPreloader) cctx.preloader()).onPartitionEvicted(this, updateSeq);

      clearDeferredDeletes();

      return true;
    }

    return false;
  }

  /** Clears swap entries for evicted partition. */
  private void clearSwap() {
    assert state() == EVICTED;
    assert !GridQueryProcessor.isEnabled(cctx.config())
        : "Indexing needs to have unswapped values.";

    try {
      GridCloseableIterator<Map.Entry<byte[], GridCacheSwapEntry>> it = cctx.swap().iterator(id);

      boolean isLocStore = cctx.store().isLocal();

      if (it != null) {
        // We can safely remove these values because no entries will be created for evicted
        // partition.
        while (it.hasNext()) {
          Map.Entry<byte[], GridCacheSwapEntry> entry = it.next();

          byte[] keyBytes = entry.getKey();

          KeyCacheObject key = cctx.toCacheKeyObject(keyBytes);

          cctx.swap().remove(key);

          if (isLocStore) cctx.store().remove(null, key.value(cctx.cacheObjectContext(), false));
        }
      }
    } catch (IgniteCheckedException e) {
      U.error(log, "Failed to clear swap for evicted partition: " + this, e);
    }
  }

  /** */
  void onUnlock() {
    tryEvict(true);
  }

  /**
   * @param topVer Topology version.
   * @return {@code True} if local node is primary for this partition.
   */
  public boolean primary(AffinityTopologyVersion topVer) {
    return cctx.affinity().primary(cctx.localNode(), id, topVer);
  }

  /** Clears values for this partition. */
  private void clearAll() {
    GridCacheVersion clearVer = cctx.versions().next();

    boolean swap = cctx.isSwapOrOffheapEnabled();

    boolean rec = cctx.events().isRecordable(EVT_CACHE_REBALANCE_OBJECT_UNLOADED);

    Iterator<GridDhtCacheEntry> it = map.values().iterator();

    GridCloseableIterator<Map.Entry<byte[], GridCacheSwapEntry>> swapIt = null;

    if (swap
        && GridQueryProcessor.isEnabled(cctx.config())) { // Indexing needs to unswap cache values.
      Iterator<GridDhtCacheEntry> unswapIt = null;

      try {
        swapIt = cctx.swap().iterator(id);
        unswapIt = unswapIterator(swapIt);
      } catch (Exception e) {
        U.error(log, "Failed to clear swap for evicted partition: " + this, e);
      }

      if (unswapIt != null) it = F.concat(it, unswapIt);
    }

    try {
      while (it.hasNext()) {
        GridDhtCacheEntry cached = it.next();

        try {
          if (cached.clearInternal(clearVer, swap)) {
            map.remove(cached.key(), cached);

            if (!cached.isInternal()) {
              mapPubSize.decrement();

              if (rec)
                cctx.events()
                    .addEvent(
                        cached.partition(),
                        cached.key(),
                        cctx.localNodeId(),
                        (IgniteUuid) null,
                        null,
                        EVT_CACHE_REBALANCE_OBJECT_UNLOADED,
                        null,
                        false,
                        cached.rawGet(),
                        cached.hasValue(),
                        null,
                        null,
                        null);
            }
          }
        } catch (IgniteCheckedException e) {
          U.error(log, "Failed to clear cache entry for evicted partition: " + cached, e);
        }
      }
    } finally {
      U.close(swapIt, log);
    }
  }

  /**
   * @param it Swap iterator.
   * @return Unswapping iterator over swapped entries.
   */
  private Iterator<GridDhtCacheEntry> unswapIterator(
      final GridCloseableIterator<Map.Entry<byte[], GridCacheSwapEntry>> it) {
    if (it == null) return null;

    return new Iterator<GridDhtCacheEntry>() {
      /** */
      GridDhtCacheEntry lastEntry;

      @Override
      public boolean hasNext() {
        return it.hasNext();
      }

      @Override
      public GridDhtCacheEntry next() {
        Map.Entry<byte[], GridCacheSwapEntry> entry = it.next();

        byte[] keyBytes = entry.getKey();

        try {
          KeyCacheObject key = cctx.toCacheKeyObject(keyBytes);

          lastEntry = (GridDhtCacheEntry) cctx.cache().entryEx(key, false);

          lastEntry.unswap(true);

          return lastEntry;
        } catch (IgniteCheckedException e) {
          throw new CacheException(e);
        }
      }

      @Override
      public void remove() {
        map.remove(lastEntry.key(), lastEntry);
      }
    };
  }

  /** */
  private void clearDeferredDeletes() {
    rmvQueue.forEach(
        new CI1<T2<KeyCacheObject, GridCacheVersion>>() {
          @Override
          public void apply(T2<KeyCacheObject, GridCacheVersion> t) {
            cctx.dht().removeVersionedEntry(t.get1(), t.get2());
          }
        });
  }

  /** {@inheritDoc} */
  @Override
  public int hashCode() {
    return id;
  }

  /** {@inheritDoc} */
  @SuppressWarnings({"OverlyStrongTypeCast"})
  @Override
  public boolean equals(Object obj) {
    return obj instanceof GridDhtLocalPartition
        && (obj == this || ((GridDhtLocalPartition) obj).id() == id);
  }

  /** {@inheritDoc} */
  @Override
  public int compareTo(@NotNull GridDhtLocalPartition part) {
    if (part == null) return 1;

    return Integer.compare(id, part.id());
  }

  /** {@inheritDoc} */
  @Override
  public String toString() {
    return S.toString(
        GridDhtLocalPartition.class,
        this,
        "state",
        state(),
        "reservations",
        reservations(),
        "empty",
        map.isEmpty(),
        "createTime",
        U.format(createTime),
        "mapPubSize",
        mapPubSize);
  }
}
  /** {@inheritDoc} */
  @SuppressWarnings({"MismatchedQueryAndUpdateOfCollection"})
  @Nullable
  @Override
  public GridDhtPartitionMap update(
      @Nullable GridDhtPartitionExchangeId exchId, GridDhtPartitionFullMap partMap) {
    if (log.isDebugEnabled())
      log.debug(
          "Updating full partition map [exchId=" + exchId + ", parts=" + fullMapString() + ']');

    assert partMap != null;

    lock.writeLock().lock();

    try {
      if (stopping) return null;

      if (exchId != null && lastExchangeId != null && lastExchangeId.compareTo(exchId) >= 0) {
        if (log.isDebugEnabled())
          log.debug(
              "Stale exchange id for full partition map update (will ignore) [lastExchId="
                  + lastExchangeId
                  + ", exchId="
                  + exchId
                  + ']');

        return null;
      }

      if (node2part != null && node2part.compareTo(partMap) >= 0) {
        if (log.isDebugEnabled())
          log.debug(
              "Stale partition map for full partition map update (will ignore) [lastExchId="
                  + lastExchangeId
                  + ", exchId="
                  + exchId
                  + ", curMap="
                  + node2part
                  + ", newMap="
                  + partMap
                  + ']');

        return null;
      }

      long updateSeq = this.updateSeq.incrementAndGet();

      if (exchId != null) lastExchangeId = exchId;

      if (node2part != null) {
        for (GridDhtPartitionMap part : node2part.values()) {
          GridDhtPartitionMap newPart = partMap.get(part.nodeId());

          // If for some nodes current partition has a newer map,
          // then we keep the newer value.
          if (newPart != null && newPart.updateSequence() < part.updateSequence()) {
            if (log.isDebugEnabled())
              log.debug(
                  "Overriding partition map in full update map [exchId="
                      + exchId
                      + ", curPart="
                      + mapString(part)
                      + ", newPart="
                      + mapString(newPart)
                      + ']');

            partMap.put(part.nodeId(), part);
          }
        }

        for (Iterator<UUID> it = partMap.keySet().iterator(); it.hasNext(); ) {
          UUID nodeId = it.next();

          if (!cctx.discovery().alive(nodeId)) {
            if (log.isDebugEnabled())
              log.debug(
                  "Removing left node from full map update [nodeId="
                      + nodeId
                      + ", partMap="
                      + partMap
                      + ']');

            it.remove();
          }
        }
      }

      node2part = partMap;

      Map<Integer, Set<UUID>> p2n = new HashMap<>(cctx.affinity().partitions(), 1.0f);

      for (Map.Entry<UUID, GridDhtPartitionMap> e : partMap.entrySet()) {
        for (Integer p : e.getValue().keySet()) {
          Set<UUID> ids = p2n.get(p);

          if (ids == null)
            // Initialize HashSet to size 3 in anticipation that there won't be
            // more than 3 nodes per partitions.
            p2n.put(p, ids = U.newHashSet(3));

          ids.add(e.getKey());
        }
      }

      part2node = p2n;

      boolean changed = checkEvictions(updateSeq);

      consistencyCheck();

      if (log.isDebugEnabled()) log.debug("Partition map after full update: " + fullMapString());

      return changed ? localPartitionMap() : null;
    } finally {
      lock.writeLock().unlock();
    }
  }
  /**
   * Updates value for single partition.
   *
   * @param p Partition.
   * @param nodeId Node ID.
   * @param state State.
   * @param updateSeq Update sequence.
   */
  @SuppressWarnings({"MismatchedQueryAndUpdateOfCollection"})
  private void updateLocal(int p, UUID nodeId, GridDhtPartitionState state, long updateSeq) {
    assert lock.isWriteLockedByCurrentThread();
    assert nodeId.equals(cctx.nodeId());

    // In case if node joins, get topology at the time of joining node.
    ClusterNode oldest = CU.oldestAliveCacheServerNode(cctx.shared(), topVer);

    assert oldest != null;

    // If this node became the oldest node.
    if (oldest.id().equals(cctx.nodeId())) {
      long seq = node2part.updateSequence();

      if (seq != updateSeq) {
        if (seq > updateSeq) {
          if (this.updateSeq.get() < seq) {
            // Update global counter if necessary.
            boolean b = this.updateSeq.compareAndSet(this.updateSeq.get(), seq + 1);

            assert b
                : "Invalid update sequence [updateSeq="
                    + updateSeq
                    + ", seq="
                    + seq
                    + ", curUpdateSeq="
                    + this.updateSeq.get()
                    + ", node2part="
                    + node2part.toFullString()
                    + ']';

            updateSeq = seq + 1;
          } else updateSeq = seq;
        }

        node2part.updateSequence(updateSeq);
      }
    }

    GridDhtPartitionMap map = node2part.get(nodeId);

    if (map == null)
      node2part.put(
          nodeId,
          map =
              new GridDhtPartitionMap(
                  nodeId,
                  updateSeq,
                  Collections.<Integer, GridDhtPartitionState>emptyMap(),
                  false));

    map.updateSequence(updateSeq);

    map.put(p, state);

    Set<UUID> ids = part2node.get(p);

    if (ids == null) part2node.put(p, ids = U.newHashSet(3));

    ids.add(nodeId);
  }
  /** {@inheritDoc} */
  @SuppressWarnings({"MismatchedQueryAndUpdateOfCollection"})
  @Nullable
  @Override
  public GridDhtPartitionMap update(
      @Nullable GridDhtPartitionExchangeId exchId, GridDhtPartitionMap parts) {
    if (log.isDebugEnabled())
      log.debug(
          "Updating single partition map [exchId=" + exchId + ", parts=" + mapString(parts) + ']');

    if (!cctx.discovery().alive(parts.nodeId())) {
      if (log.isDebugEnabled())
        log.debug(
            "Received partition update for non-existing node (will ignore) [exchId="
                + exchId
                + ", parts="
                + parts
                + ']');

      return null;
    }

    lock.writeLock().lock();

    try {
      if (stopping) return null;

      if (lastExchangeId != null && exchId != null && lastExchangeId.compareTo(exchId) > 0) {
        if (log.isDebugEnabled())
          log.debug(
              "Stale exchange id for single partition map update (will ignore) [lastExchId="
                  + lastExchangeId
                  + ", exchId="
                  + exchId
                  + ']');

        return null;
      }

      if (exchId != null) lastExchangeId = exchId;

      if (node2part == null)
        // Create invalid partition map.
        node2part = new GridDhtPartitionFullMap();

      GridDhtPartitionMap cur = node2part.get(parts.nodeId());

      if (cur != null && cur.updateSequence() >= parts.updateSequence()) {
        if (log.isDebugEnabled())
          log.debug(
              "Stale update sequence for single partition map update (will ignore) [exchId="
                  + exchId
                  + ", curSeq="
                  + cur.updateSequence()
                  + ", newSeq="
                  + parts.updateSequence()
                  + ']');

        return null;
      }

      long updateSeq = this.updateSeq.incrementAndGet();

      node2part = new GridDhtPartitionFullMap(node2part, updateSeq);

      boolean changed = false;

      if (cur == null || !cur.equals(parts)) changed = true;

      node2part.put(parts.nodeId(), parts);

      part2node = new HashMap<>(part2node);

      // Add new mappings.
      for (Integer p : parts.keySet()) {
        Set<UUID> ids = part2node.get(p);

        if (ids == null)
          // Initialize HashSet to size 3 in anticipation that there won't be
          // more than 3 nodes per partition.
          part2node.put(p, ids = U.newHashSet(3));

        changed |= ids.add(parts.nodeId());
      }

      // Remove obsolete mappings.
      if (cur != null) {
        for (Integer p : F.view(cur.keySet(), F0.notIn(parts.keySet()))) {
          Set<UUID> ids = part2node.get(p);

          if (ids != null) changed |= ids.remove(parts.nodeId());
        }
      }

      changed |= checkEvictions(updateSeq);

      consistencyCheck();

      if (log.isDebugEnabled()) log.debug("Partition map after single update: " + fullMapString());

      return changed ? localPartitionMap() : null;
    } finally {
      lock.writeLock().unlock();
    }
  }