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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More system design questions
- Why does an index's internal data structure matter if it all ends up 'faster than a scan'?
- Why is disk I/O the thing index structures are actually optimizing for?
- Why can't a hash index handle range queries?
- What makes a bitmap index different from a B-tree, and when is it better?
- Why do B-trees stay balanced automatically as data is inserted?
- Why does a database need an index at all — why can't it just scan the table?
- When is a hash index better than a B-tree index?
- What is a composite index and why does column order matter?
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