Scaling Search and Retrieval for Contextual AI

Chapter 2. Data Structures for Search

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At the core of every fast, intelligent hybrid search and retrieval engine is a sophisticated arrangement of data structures grounded in computer science theory and practice. These structures transform a user’s imprecise query into a ranked, relevant set of results within milliseconds, even when searching billions of documents. While search often feels easy and instant, the underlying technology depends on indexes, graphs, bitmaps, and trees engineered for maximum speed and scale, as illustrated in Figure 2-1. This chapter examines these core components, explains how they operate, highlights their importance, and discusses the trade-offs that influence their design.

Figure 2-1. Components of a modern Search Engine

We begin with traditional search foundations: inverted indexes and term dictionary structures, which support keyword retrieval, along with postings ...