checkpoint_warning

checkpoint_warning — Sets the maximum time before warning if checkpoints triggered by WAL volume happen too frequently. Observed in PG9.0–19 Beta 3; its last measured boot default is 30 s in PG19 Beta 3, with sighup context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA.

Note

Fact — official short description: “Sets the maximum time before warning if checkpoints triggered by WAL volume happen too frequently.”

Identity

Type , Valueinteger: Upstream pg_settings type
Context , Valuesighup: Takes effect after configuration reload
Unit , Values: Raw unit
Range , Value0 – 2147483647: Raw limits in the last observed version
Enum values , Value—: — for non-enum types
Category , ValueWrite-Ahead Log / Checkpoints: Upstream classification
Latest boot value , Value30: 30 s

Lifecycle

Fact	Value
First observed	PG9.0 (research boundary)
Present in	PG9.0–19 Beta 3
Removed in	No
Introduction commit	Not asserted: predates the PG9.0 research boundary
Commit date	—
Discussion	—

Default history

Measured PG9.0–19 Beta 3 boot defaults
Versions	Raw `boot_val`	Unit	Human value
PG9.0–19 Beta 3	`30`	`s`	30 s

How it works

Sets the maximum time before warning if checkpoints triggered by WAL volume happen too frequently. A configuration reload applies a new value; existing work already in flight is not retroactively changed.

This parameter only emits a log warning when WAL-volume checkpoints occur closer together than the threshold. It does not delay checkpoints; frequent warnings normally point to max_wal_size being too small for the WAL generation rate.

Monitor and change checkpoint_warning together with checkpoint_flush_after, checkpoint_timeout, checkpoint_completion_target. Validate on the relevant server role and real workload, then use its sighup context to choose session change, reload, or restart; a historical boot default is not the current effective value.

Tuning advice

Tip

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

Workload	Guidance
OLTP	Establish durability and recovery objectives first, then tune checkpoint_warning from WAL rate, flush latency, checkpoints, and peak pg_wal usage. Validate every change with crash/recovery and archive monitoring.
OLAP	Provision WAL, archive bandwidth, and recovery I/O for bulk-load peaks. Coordinate load pacing and checkpoints when reducing spikes; never break the recovery chain for throughput.
Small nodes	Start from safe defaults or the measured Pigsty value and set explicit alerts for limited disk capacity. Do not disable durability or break the recovery chain merely to save modest I/O.

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: PG9.0–19 Beta 3 unmodified; OLAP: PG9.0–19 Beta 3 unmodified; CRIT: PG9.0–19 Beta 3 unmodified; TINY: PG9.0–19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

Common pitfalls

Treating the warning threshold as a control that delays or throttles checkpoints.
Setting zero and silencing evidence of WAL-volume checkpoints.
Raising the threshold instead of investigating WAL rate, max_wal_size, and requested-checkpoint frequency.
Setting checkpoint_warning above checkpoint_timeout and expecting time-based checkpoints to produce this warning.

checkpoint_flush_after · checkpoint_timeout · checkpoint_completion_target · max_wal_size · min_wal_size · archive_cleanup_command