/**
   * Should only be called by ColumnFamilyStore.apply via Keyspace.apply, which supplies the
   * appropriate OpOrdering.
   *
   * <p>replayPosition should only be null if this is a secondary index, in which case it is
   * *expected* to be null
   */
  long put(PartitionUpdate update, UpdateTransaction indexer, OpOrder.Group opGroup) {
    AtomicBTreePartition previous = partitions.get(update.partitionKey());

    long initialSize = 0;
    if (previous == null) {
      final DecoratedKey cloneKey = allocator.clone(update.partitionKey(), opGroup);
      AtomicBTreePartition empty = new AtomicBTreePartition(cfs.metadata, cloneKey, allocator);
      // We'll add the columns later. This avoids wasting works if we get beaten in the putIfAbsent
      previous = partitions.putIfAbsent(cloneKey, empty);
      if (previous == null) {
        previous = empty;
        // allocate the row overhead after the fact; this saves over allocating and having to free
        // after, but
        // means we can overshoot our declared limit.
        int overhead = (int) (cloneKey.getToken().getHeapSize() + ROW_OVERHEAD_HEAP_SIZE);
        allocator.onHeap().allocate(overhead, opGroup);
        initialSize = 8;
      } else {
        allocator.reclaimer().reclaimImmediately(cloneKey);
      }
    }

    long[] pair = previous.addAllWithSizeDelta(update, opGroup, indexer);
    minTimestamp = Math.min(minTimestamp, previous.stats().minTimestamp);
    liveDataSize.addAndGet(initialSize + pair[0]);
    columnsCollector.update(update.columns());
    statsCollector.update(update.stats());
    currentOperations.addAndGet(update.operationCount());
    return pair[1];
  }