Why PostgreSQL VACUUM Monitoring Matters for Preventing Table Bloat

Table bloat in PostgreSQL can degrade performance for weeks before it is noticed, since symptoms like growing disk usage and slower queries appear indirectly. The cause lies in MVCC, where updates and deletes leave dead row versions that only VACUUM can reclaim, and only once no running transaction still needs them. Autovacuum may be enabled yet still fall behind, because its default trigger thresholds scale poorly on very large tables. Long-running transactions, idle sessions, and replication slots can also hold back cleanup, while cost-limited workers may never catch up on write-heavy tables. Effective monitoring of dead tuples and vacuum activity is therefore needed to catch these problems early.