PostgreSQL VACUUM: Understand Dead Tuples
Updates create old row versions that need cleanup, but manual VACUUM is not a universal speed button. This guide gives you a small, testable way to approach the issue before changing a live system.
A practical workflow
- Check autovacuum activity, table size and dead-tuple estimates before changing settings.
- Investigate long-lived transactions and high-churn tables that prevent cleanup from keeping up.
What to check
VACUUM FULL rewrites and locks a table; plan it separately rather than using it as a routine fix. Compare the result with the original problem and record what changed. If a measurement or test does not support the change, revisit the assumption rather than adding more complexity.
Keep the experiment small enough to reverse. Document the starting state, the change and the result so another person can repeat the process. Product menus and versions can change, so check the current documentation for your environment.
Official reference: Read the documentation.