Also called: WAL inspection extension, pg_get_wal_stats
In plain English
pg_walinspect is a contrib extension (PostgreSQL 15+) that lets you decode the write-ahead log from inside SQL. pg_get_wal_records_info() lists individual records between two LSNs, and pg_get_wal_stats() summarises them per resource manager — counts, tuple/" title="Tuple">record bytes, and full-page-image bytes. It is the in-database equivalent of the command-line pg_waldump.
Why it matters
It turns WAL volume from a mystery into something measurable. You can see exactly which subsystem (heap, btree, etc.) is generating WAL and how much of it is full-page images versus real changes — the key to deciding whether to space out checkpoints, enable compression, or fix a write pattern.