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Pg_waldump

As explained in PostgreSQL Mistakes and How to Avoid Them

pg_waldump is a PostgreSQL command-line utility that displays and parses write-ahead log records.

pg_waldump is a PostgreSQL command-line utility for displaying and parsing write-ahead log records. In a backup test, it provides an early check that the WAL needed for recovery is readable and parsable before starting the restored instance. section 9.4

Use pg_waldump as one step in a restore fire drill:

  • Copy the base backup into a testing PGDATA directory. section 9.4
  • Verify the base backup with pg_verifybackup. section 9.4
  • Copy WAL generated since the backup into the test environment. section 9.4
  • Call pg_waldump on those WAL files, then start PostgreSQL and confirm that recovery reaches a consistent state. section 9.4

Parsing WAL does not prove that every restored table page is readable. For deeper verification, inspect relation pages with pageinspect, checking page headers and checksums; automate the procedure and alert on errors. section 9.4

How PostgreSQL Mistakes and How to Avoid Them covers it

How deep it goes
Explains its role in WAL parsing and restore validation, but defers page-level checks to pageinspect.
Examples
Uses a restored PGDATA directory, copied WAL files, pg_verifybackup, and a PostgreSQL recovery test.
What it assumes
Assumes a PostgreSQL base backup, its subsequent WAL, and a separate testing environment for restoration.
What you can do after
Operate pg_waldump to detect unparsable WAL during a backup restore test.
How it connects
Connects backup testing with WAL, recovery, pg_verifybackup, and pageinspect.
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