postgres-impl-vacuum-bloat

Quick Reference :

Every UPDATE and DELETE in PostgreSQL leaves the old row version on disk as a dead tuple (MVCC). VACUUM reclaims that space; autovacuum runs VACUUM in the background. When autovacuum falls behind, tables bloat (dead tuples outnumber live tuples), queries scan more pages than needed, and disk usage climbs. This skill diagnoses bloat, tunes autovacuum, maximizes HOT updates, and handles transaction-ID wraparound.

Core decision summary :