/**
   * @param cctx Cache context.
   * @param completionCb Callback to invoke when future is completed.
   * @param writeVer Write version.
   * @param updateReq Update request.
   * @param updateRes Update response.
   */
  public GridDhtAtomicUpdateFuture(
      GridCacheContext cctx,
      CI2<GridNearAtomicUpdateRequest, GridNearAtomicUpdateResponse> completionCb,
      GridCacheVersion writeVer,
      GridNearAtomicUpdateRequest updateReq,
      GridNearAtomicUpdateResponse updateRes) {
    this.cctx = cctx;
    this.writeVer = writeVer;

    futVer = cctx.versions().next(updateReq.topologyVersion());
    this.updateReq = updateReq;
    this.completionCb = completionCb;
    this.updateRes = updateRes;

    if (log == null) log = U.logger(cctx.kernalContext(), logRef, GridDhtAtomicUpdateFuture.class);

    keys = new ArrayList<>(updateReq.keys().size());
    mappings = U.newHashMap(updateReq.keys().size());

    boolean topLocked =
        updateReq.topologyLocked() || (updateReq.fastMap() && !updateReq.clientRequest());

    waitForExchange = !topLocked;
  }
  /** 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);
    }
  }