cluster_name

cluster_name is the PostgreSQL setting that defines the name of the cluster, which is included in the process title.

Note

Fact — official short description: “Sets the name of the cluster, which is included in the process title.”

Identity

Type , Valuestring: Upstream pg_settings type
Context , Valuepostmaster: Requires a server restart
Unit , Value—: Raw unit
Range , Value—: Raw limits in the last observed version
Enum values , Value—: — for non-enum types
Category , ValueReporting and Logging / Process Title: Upstream classification
Latest boot value , Value"": empty string

Lifecycle

Fact	Value
First observed	PG9.5
Present in	PG9.5–19 Beta 3
Removed in	No
Introduction commit	`51adcaa0df81` — Add cluster_name GUC which is included in process titles if set.
Commit date	2014-06-29
Discussion	—

Default history

Measured PG9.0–19 Beta 3 boot defaults
Versions	Raw `boot_val`	Unit	Human value
PG9.5–19 Beta 3	`""`	—	empty string

How it works

cluster_name sets the name of the cluster, which is included in the process title. It is an operator-facing label included in process titles and can distinguish several clusters running on one host; it is not a database identifier.

cluster_name is a POSTMASTER-context setting: PostgreSQL reads it during server startup, and a configuration reload or session SET cannot activate a new value.

Process titles complement application_name, cluster_name, pg_stat_activity, and log_line_prefix, allowing operating-system observations to be joined with database activity.

Tuning advice

Tip

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

Workload	Guidance
OLTP	Keep cluster_name enabled or populated for operator clarity unless profiling proves material overhead. Use stable, non-secret labels that match monitoring inventory.
OLAP	Preserve cluster_name so long jobs can be attributed from operating-system and PostgreSQL views; use application_name for finer job identity.
Small nodes	Do not tune cluster_name for capacity. Its observability value normally outweighs negligible overhead, but avoid high-cardinality or sensitive labels.

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: PG9.5–19 Beta 3 unmodified; OLAP: PG9.5–19 Beta 3 unmodified; CRIT: PG9.5–19 Beta 3 unmodified; TINY: PG9.5–19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

Common pitfalls

Expecting a reload or SET to activate cluster_name, although it requires a controlled server restart.
Putting secrets or unbounded high-cardinality data into operator-visible process labels.
Using inconsistent cluster, application, and process labels that cannot be joined across monitoring systems.
Changing cluster_name globally without a rollback plan and a client or operational compatibility test.

application_name · update_process_title · log_line_prefix · log_timezone · log_hostname