wal_consistency_checking

wal_consistency_checking — Sets the WAL resource managers for which WAL consistency checks are done. Observed in PG10–19 Beta 3; its last measured boot default is empty string in PG19 Beta 3, with superuser context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA.

Note

Fact — official short description: “Sets the WAL resource managers for which WAL consistency checks are done.”

Identity

Type , Valuestring: Upstream pg_settings type
Context , Valuesuperuser: Settable at runtime by a superuser
Unit , Value—: Raw unit
Range , Value—: Raw limits in the last observed version
Enum values , Value—: — for non-enum types
Category , ValueDeveloper Options: Upstream classification
Latest boot value , Value"": empty string

Lifecycle

Fact	Value
First observed	PG10
Present in	PG10–19 Beta 3
Removed in	No
Introduction commit	`a507b86900f6` — Add WAL consistency checking facility.
Commit date	2017-02-08
Discussion	—

Default history

Measured PG9.0–19 Beta 3 boot defaults
Versions	Raw `boot_val`	Unit	Human value
PG10–19 Beta 3	`""`	—	empty string

How it works

wal_consistency_checking names WAL resource managers whose redo routines should be verified. For selected records, PostgreSQL includes full-page images and after replay compares the resulting buffers with those images.

Unexpected differences terminate recovery with a fatal error; known nondeterministic differences such as some hint bits are handled specially. all enables every supported resource manager.

The added full-page images can greatly increase WAL volume and replay work. This finds redo implementation bugs; it is not a general on-disk checksum, backup verification, or corruption repair tool. Its superuser context permits an authorized session change without a server restart.

Tuning advice

Tip

Advice. These are workload-specific starting points and must be validated with measurements.

Workload	Guidance
OLTP	Do not tune production OLTP with wal_consistency_checking. Enable it only for a bounded reproduction with an owner, log/disk budget, rollback condition, and evidence-capture plan; restore the default immediately afterward.
OLAP	Long analytical runs can amplify wal_consistency_checking’s debug overhead and artifacts. Prefer standard EXPLAIN and statistics first, and isolate any developer experiment from normal users.
Small nodes	Keep wal_consistency_checking at its upstream default. A small host has less spare CPU, disk, connection, and log capacity for developer instrumentation.

Pigsty

Values use the fixed 8-vCPU, 32-GiB, 100-GiB SSD fixture and render the current Pigsty templates for PG19 Beta 3; this does not assert current Pigsty support for that historical or beta release.

Template	Effective value	Versus upstream boot	Source expression
OLTP	Unmodified	—	—
OLAP	Unmodified	—	—
CRIT	Unmodified	—	—
TINY	Unmodified	—	—

Caution

Advice — pending human review. Fact from the current Pigsty template projection: OLTP: PG10–19 Beta 3 unmodified; OLAP: PG10–19 Beta 3 unmodified; CRIT: PG10–19 Beta 3 unmodified; TINY: PG10–19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

Common pitfalls

Leaving wal_consistency_checking enabled after the bounded diagnostic or recovery task.
Running the experiment on the only copy of production data.
Underestimating log, core-file, temporary-file, WAL, CPU, or connection-slot amplification.
Treating a server that merely starts or completes a query as proof that data and behavior are correct.

full_page_writes · wal_log_hints · ignore_invalid_pages · ignore_checksum_failure · wal_level