htree

HTree is a term used in computer science to describe a family of hierarchical tree structures and memory layouts rather than a single, canonical data structure. The name is applied in several contexts where the goal is to organize data in a way that emphasizes locality, scalability, and efficient traversal.

One prominent usage is the H-tree layout, a recursive arrangement of tree nodes on a grid designed to minimize cache misses during tree traversals by preserving locality across levels. In such layouts, nodes at each level are placed along axes or lines that reflect the tree’s branching, reducing pointer chasing and improving spatial locality on modern memory hierarchies.

HTree-inspired structures are also used in databases, file systems, and key-value stores to implement hierarchical, hash-based indices. These systems partition data into buckets at multiple levels and route lookups through progressively finer partitions, balancing load and enabling parallelism.

In software design, HTree can refer to a generic hierarchical tree used to model nested keys, categories, or configuration namespaces. Common considerations include balancing to keep height logarithmic, concurrency control, persistence, and the trade-offs between fast single-key lookups and range queries or scans.

See also: B-tree, Merkle tree, quadtree, H-Tree layout, cache-conscious data structures.