Databases · Middle · Question 46 of 75

What does VACUUM do?

1Compresses the database file to the smallest size
2Deletes all rows older than a week
✓Correct answer: Reclaims space from dead row versions for reuse, updates the visibility map and prevents transaction ID wraparound

Explanation

Autovacuum runs it automatically. Regular VACUUM doesn't shrink the file; VACUUM FULL does but locks the table.

Further reading

PostgreSQL: Routine vacuuming ↗

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