Databases · Middle · Question 12 of 75

In `EXPLAIN ANALYZE` the planner estimated 10 rows but got 500,000. What does it suggest?

✓Correct answer: Outdated or insufficient statistics; run ANALYZE or improve statistics so the planner picks a better plan
2The query returned wrong results
3The index is corrupted and must be dropped

Explanation

Bad estimates lead to bad plans, like a nested loop over half a million rows. Correlated columns may need extended statistics (CREATE STATISTICS).

Further reading

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