For a high-performance B+Tree, the memory layout of each node must be a single contiguous block. This improves locality of reference, increasing the likelihood that the node's contents reside in the CPU cache. In C++, achieving this means forgoing the use of std::vector, as it introduces a layer of indirection through a separate memory allocation. The solution to this problem though inevitably increases the implementation complexity and is mired with hidden drawbacks. Nevertheless, this is still...