You notice EXPLAIN ANALYZE reports a much higher execution time than expected for a query with a JOIN. What could be a reason?

hard📝 Application Q9 of 15

PostgreSQL - Performance Tuning

You notice EXPLAIN ANALYZE reports a much higher execution time than expected for a query with a JOIN. What could be a reason?

AThe JOIN is causing a large number of rows to be processed, increasing time

BEXPLAIN ANALYZE always overestimates execution time

CThe query is not actually executed by EXPLAIN ANALYZE

DThe database is ignoring the JOIN condition

Step-by-Step Solution

Solution:

Step 1: Understand JOIN impact on execution time
JOINs can multiply rows processed, increasing execution time significantly.
Step 2: Evaluate other options
EXPLAIN ANALYZE shows actual time (not overestimated), it executes the query, and does not ignore JOIN conditions.
Final Answer:
The JOIN is causing a large number of rows to be processed, increasing time -> Option A
Quick Check:
JOINs can increase rows and time [OK]

Quick Trick: JOINs can multiply rows, increasing execution time [OK]

Common Mistakes:

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