Semab Tariq covers autovacuum:
However, one side effect of MVCC is the creation of dead tuples—old versions of data rows that are no longer needed but still occupy space.
Dead tuples also lead to a phenomenon known as table bloat, which refers to the excessive unused space in a table caused by dead tuples that haven’t been cleaned up, resulting in inefficient storage and reduced performance
To address the issues of dead tuples and table bloat, autovacuum comes into play. It’s an automatic process designed to clean up these dead tuples and maintain optimal database performance.
Read on for a list of scenarios that can trigger autovacuum.