[Solved] You want to speed up queries filtering by LOWER(username). What is the best indexing approach? — Ans: Create a functional index on LOWER(username) | PostgreSQL

PostgreSQL - Indexing Strategies

You want to speed up queries filtering by LOWER(username). What is the best indexing approach?

ACreate a functional index on LOWER(username)

BCreate a normal index on username

CCreate an index on username with COLLATE

DCreate no index and rely on sequential scans

Step-by-Step Solution

Solution:

Step 1: Understand functional indexes
Functional indexes index the result of a function applied to a column, enabling fast queries using that function.
Step 2: Apply to LOWER(username) queries
Creating an index on LOWER(username) allows queries filtering with LOWER(username) to use the index efficiently.
Final Answer:
Create a functional index on LOWER(username) -> Option A
Quick Check:
Functional indexes speed queries using functions on columns [OK]

Quick Trick: Use functional indexes for queries with functions on columns [OK]

Common Mistakes:

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You want to speed up queries filtering by LOWER(username). What is the best indexing approach?