When should you NOT use an inverted index?
Inverted indexes excel at full-text search but are overkill for range queries ('age > 30') or numeric joins. They also require write-time work—every document insert updates multiple posting lists. For write-heavy systems (event streams, time series) without full-text search needs, column indexes or B-trees are simpler.
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The Inverted IndexA sorted dictionary mapping terms to document IDs. Transform search from O(corpus size) to O(1) lookup, enabling full-text search at scale.
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