You want to compare the performance of two queries on a large table. Which approach using EXPLAIN ANALYZE is best?

hard📝 Application Q8 of 15

PostgreSQL - Performance Tuning

You want to compare the performance of two queries on a large table. Which approach using EXPLAIN ANALYZE is best?

ARun EXPLAIN ANALYZE on a different table for comparison

BRun EXPLAIN only (without ANALYZE) on both queries and compare estimated costs

CRun EXPLAIN ANALYZE on one query and EXPLAIN on the other

DRun EXPLAIN ANALYZE on both queries separately and compare actual execution times

Step-by-Step Solution

Solution:

Step 1: Understand goal is to compare real performance
Actual execution times are needed, so EXPLAIN ANALYZE must be run on both queries.
Step 2: Evaluate options
Only running EXPLAIN shows estimates, mixing EXPLAIN and EXPLAIN ANALYZE is inconsistent, and comparing different tables is invalid.
Final Answer:
Run EXPLAIN ANALYZE on both queries separately and compare actual execution times -> Option D
Quick Check:
Compare real times = EXPLAIN ANALYZE both queries [OK]

Quick Trick: Use EXPLAIN ANALYZE on both queries for real time comparison [OK]

Common Mistakes:

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