[Solved] In PostgreSQL, what key benefit does an index-only scan provide over a traditional index scan? — Ans: It eliminates the need to access the main table heap for the queried columns | PostgreSQL

PostgreSQL - Indexing Strategies

In PostgreSQL, what key benefit does an index-only scan provide over a traditional index scan?

AIt automatically updates the index during the scan

BIt eliminates the need to access the main table heap for the queried columns

CIt allows scanning multiple indexes simultaneously

DIt locks the table to prevent concurrent writes

Step-by-Step Solution

Solution:

Step 1: Understand index-only scan
An index-only scan reads data directly from the index without accessing the table heap.
Step 2: Compare with regular index scan
Regular index scans use the index to find row locations but must fetch data from the heap for the actual columns.
Final Answer:
It eliminates the need to access the main table heap for the queried columns -> Option B
Quick Check:
Index-only scans avoid heap access [OK]

Quick Trick: Index-only scans skip heap access for covered columns [OK]

Common Mistakes:

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In PostgreSQL, what key benefit does an index-only scan provide over a traditional index scan?