Databases · Middle · Question 45 of 75

What does MVCC mean in PostgreSQL?

✓Correct answer: Multi-version concurrency control: updates create new row versions, so readers don't block writers and writers don't block readers
2Multiple copies of the database on different servers
3A mode where only one query runs at a time

Explanation

Each transaction sees a snapshot. Old row versions remain until VACUUM removes them once no transaction can see them.

Further reading

PostgreSQL: Concurrency control (MVCC) ↗

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