A query uses an index scan on a large table but is slower than expected. You suspect the planner is misestimating row counts. What can you do to improve scan choice?

hard📝 Application Q9 of 15

PostgreSQL - Performance Tuning

ADrop the index and recreate it with a different name.

BDisable sequential scans globally to force index scans.

CRun ANALYZE on the table to update statistics for better planner decisions.

DRewrite the query without WHERE clause.

Step-by-Step Solution

Solution:

Step 1: Understand planner statistics role
PostgreSQL uses table statistics to estimate row counts and choose scan types.
Step 2: Update statistics to fix misestimation
Running ANALYZE updates statistics, helping the planner make better scan choices.
Final Answer:
Run ANALYZE on the table to update statistics for better planner decisions. -> Option C
Quick Check:
Fix planner misestimation = C [OK]

Quick Trick: Run ANALYZE to refresh stats and improve scan plans [OK]

Common Mistakes:

Disabling sequential scans globally is risky
Dropping and renaming indexes doesn't fix stats
Removing WHERE clause removes filtering, not scan choice

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A query uses an index scan on a large table but is slower than expected. You suspect the planner is misestimating row counts. What can you do to improve scan choice?

Step 1: Understand planner statistics role

Step 2: Update statistics to fix misestimation

Final Answer:

Quick Check:

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