[Solved] What will be the output of this EXPLAIN query?EXPLAIN SELECT * FROM orders WHERE order_date > '2023-01-01';Assuming 'order_date' is not indexed and the table has 500,000 rows. | PostgreSQL

PostgreSQL - Performance Tuning

What will be the output of this EXPLAIN query?

EXPLAIN SELECT * FROM orders WHERE order_date > '2023-01-01';

Assuming 'order_date' is not indexed and the table has 500,000 rows.

AIt will show a sequential scan on the orders table.

BIt will show an index scan on the orders table.

CIt will show a bitmap index scan on the orders table.

DIt will return an error because order_date is not indexed.

Step-by-Step Solution

Solution:

Step 1: Check index presence
Since 'order_date' is not indexed, PostgreSQL cannot use an index scan.
Step 2: Determine scan type
PostgreSQL will perform a sequential scan to check all rows for the condition.
Final Answer:
It will show a sequential scan on the orders table. -> Option A
Quick Check:
Scan type without index = A [OK]

Quick Trick: No index means sequential scan by default [OK]

Common Mistakes:

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What will be the output of this EXPLAIN query?