[Solved] In PostgreSQL, what is the primary function of a Bitmap Index Scan during query execution? — Ans: To create a bitmap of matching row locations from an index before accessing the... | PostgreSQL

PostgreSQL - Performance Tuning

In PostgreSQL, what is the primary function of a Bitmap Index Scan during query execution?

ATo create a bitmap of matching row locations from an index before accessing the heap

BTo directly retrieve rows from the table without using an index

CTo perform a sequential scan on the entire table

DTo update index entries during data modification

Step-by-Step Solution

Solution:

Step 1: Understand Bitmap Index Scan
A Bitmap Index Scan builds a bitmap of tuple locations that satisfy the index condition.
Step 2: Purpose
This bitmap is then used to efficiently fetch rows from the heap in a subsequent Bitmap Heap Scan.
Final Answer:
To create a bitmap of matching row locations from an index before accessing the heap -> Option A
Quick Check:
Bitmap Index Scan does not fetch rows directly [OK]

Quick Trick: Bitmap Index Scan builds bitmap of row pointers [OK]

Common Mistakes:

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In PostgreSQL, what is the primary function of a Bitmap Index Scan during query execution?