[Solved] How does running VACUUM interact with PostgreSQL's MVCC (Multi-Version Concurrency Control) system? — Ans: VACUUM removes obsolete row versions to prevent table bloat | PostgreSQL

PostgreSQL - Transactions and Concurrency

How does running VACUUM interact with PostgreSQL's MVCC (Multi-Version Concurrency Control) system?

AVACUUM removes obsolete row versions to prevent table bloat

BVACUUM locks all rows to prevent concurrent access

CVACUUM creates new row versions for updates

DVACUUM disables MVCC temporarily during cleanup

Step-by-Step Solution

Solution:

Step 1: Understand MVCC and dead rows
MVCC keeps multiple row versions; VACUUM removes obsolete ones to avoid bloat.
Step 2: Evaluate other options
VACUUM does not lock all rows, create new versions, or disable MVCC.
Final Answer:
VACUUM removes obsolete row versions to prevent table bloat -> Option A
Quick Check:
VACUUM cleans obsolete MVCC rows [OK]

Quick Trick: VACUUM cleans old MVCC row versions to prevent bloat [OK]

Common Mistakes:

Master "Transactions and Concurrency" in PostgreSQL

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How does running VACUUM interact with PostgreSQL's MVCC (Multi-Version Concurrency Control) system?