Advanced
Database Management Systems
Q85 / 100
What is a query execution plan and how do you analyze it?
Correct! Well done.
Incorrect.
The correct answer is B) A tree of physical operations (table scans, index seeks, joins, sorts) the optimizer chose to execute a query — analyzed with EXPLAIN/EXPLAIN ANALYZE to find bottlenecks
B
Correct Answer
A tree of physical operations (table scans, index seeks, joins, sorts) the optimizer chose to execute a query — analyzed with EXPLAIN/EXPLAIN ANALYZE to find bottlenecks
Explanation
EXPLAIN (PostgreSQL) or EXPLAIN PLAN (Oracle) shows the execution plan. EXPLAIN ANALYZE actually runs and shows real vs. estimated row counts. Look for sequential scans on large tables, nested loops over large sets, and incorrect cardinality estimates.
Progress
85/100