---
title: "Index-Only Scan — Database Glossary | Xata"
description: "A query execution strategy where all required data is retrieved from the index without touching the heap table. Requires the index to cover all columns ..."
source: "https://xata.io/glossary/index-only-scan"
---

# Index-Only Scan

Indexing

A query execution strategy where all required data is retrieved from the index without touching the heap table. Requires the index to cover all columns in the query and the visibility map to confirm all-visible pages.

Related terms

[Covering Index](/glossary/covering-index)[Visibility Map](/glossary/visibility-map)

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