What is autovacuum in PostgreSQL and why is it needed?

Autovacuum in PostgreSQL is an automatic process that performs cleaning and optimization of database tables. It is necessary for:

• Removing "dead" rows that remain after updates and deletes (MVCC — Multi-Version Concurrency Control).
• Preventing table and index bloat.
• Updating statistics for the query planner to build efficient execution plans.

Without autovacuum, tables can grow quickly, performance drops, and locks increase. This process runs in the background and is automatically triggered as needed, making database administration easier.