Dynamic Interleaving of Content and Structure for Robust Indexing of Semi-Structured Hierarchical Data (Extended Version)

TL;DR

This paper introduces a robust, trie-based index for semi-structured hierarchical data that dynamically interleaves content and structure, enabling efficient and flexible CAS queries with significant performance improvements.

Contribution

It presents a novel dynamic interleaving scheme for composite keys in a trie-based index, enhancing robustness and query support for semi-structured data.

Findings

Supports a wide range of CAS queries including wildcards and descendant axes

Achieves up to two orders of magnitude performance improvement over existing methods

Demonstrates robustness against varying selectivities

Abstract

We propose a robust index for semi-structured hierarchical data that supports content-and-structure (CAS) queries specified by path and value predicates. At the heart of our approach is a novel dynamic interleaving scheme that merges the path and value dimensions of composite keys in a balanced way. We store these keys in our trie-based Robust Content-And-Structure index, which efficiently supports a wide range of CAS queries, including queries with wildcards and descendant axes. Additionally, we show important properties of our scheme, such as robustness against varying selectivities, and demonstrate improvements of up to two orders of magnitude over existing approaches in our experimental evaluation.