restart_after_crash

restart_after_crash — Reinitialize server after backend crash. Observed in PG9.1–19 Beta 3; its last measured boot default is on 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: “Reinitialize server after backend crash.”

Identity

Type , Valuebool: Upstream pg_settings type
Context , Valuesighup: Takes effect after configuration reload
Unit , Value—: Raw unit
Range , Value—: Raw limits in the last observed version
Enum values , Value—: — for non-enum types
Category , ValueError Handling: Upstream classification
Latest boot value , Valueon: on

Lifecycle

Fact	Value
First observed	PG9.1
Present in	PG9.1–19 Beta 3
Removed in	No
Introduction commit	`5ffaa9005c45` — Add restart_after_crash GUC.
Commit date	2010-07-20
Discussion	—

Default history

Measured PG9.0–19 Beta 3 boot defaults
Versions	Raw `boot_val`	Unit	Human value
PG9.1–19 Beta 3	`on`	—	on

How it works

Reinitialize server after backend crash. A configuration reload applies a new value; existing work already in flight is not retroactively changed.

After a backend crash, the default postmaster behavior terminates sibling backends, performs crash recovery, and resumes service. Turning this off leaves restart policy to an external supervisor and converts one backend failure into a full service stop.

Monitor and change restart_after_crash together with data_sync_retry, recovery_init_sync_method, fsync. 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	Change restart_after_crash only from an explicit failure model and measured evidence. Validate in a session/test environment, deploy according to its context, and retain a rollback value.
OLAP	Test separately under long queries, batch jobs, and peak concurrency rather than copying OLTP assumptions to analytical nodes.
Small nodes	Keep the default without a concrete problem; small systems should not trade global compatibility or failure semantics for a marginal gain.

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: PG9.1–19 Beta 3 unmodified; OLAP: PG9.1–19 Beta 3 unmodified; CRIT: PG9.1–19 Beta 3 unmodified; TINY: PG9.1–19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

Common pitfalls

Confusing the boot default of restart_after_crash with its current effective value.
Ignoring its sighup context when deciding when it takes effect.
Changing several interacting settings at once and losing causal evidence.
Rolling out globally without testing the real failure or workload boundary.

data_sync_retry · recovery_init_sync_method · fsync · full_page_writes · exit_on_error · statement_timeout