in_hot_standby

in_hot_standby shows whether hot standby is currently active. It is read-only metadata in PG14–18, not a runtime tuning control.

Note

Fact — official short description: “Shows whether hot standby is currently active.”

Identity

Type , Valuebool: Upstream pg_settings type
Context , Valueinternal: Internal/preset and not user-settable
Unit , Value—: Raw unit
Range , Value—: Raw limits in the last observed version
Enum values , Value—: — for non-enum types
Category , ValuePreset Options: Upstream classification
Latest boot value , Valueoff: off

Lifecycle

Fact	Value
First observed	PG14
Present in	PG14–19 Beta 3
Removed in	No
Introduction commit	`bf8a662c9afa` — Introduce a new GUC_REPORT setting “in_hot_standby”.
Commit date	2021-01-05
Discussion	thread 1

Default history

Measured PG9.0–19 Beta 3 boot defaults
Versions	Raw `boot_val`	Unit	Human value
PG14–19 Beta 3	`off`	—	off

How it works

Shows whether hot standby is currently active. It is read-only and cannot be changed with SET or configuration-file edits.

It changes as recovery enters or leaves hot-standby operation and is intended for feature detection by SQL code.

Interpret it with hot_standby, max_standby_streaming_delay, hot_standby_feedback. Applications and operations tooling may read in_hot_standby for capability or environment detection, but cannot SET it; cross-cluster comparisons must account for build, initdb, and current-database differences.

Tuning advice

Tip

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

Workload	Guidance
OLTP	Not tunable. Record in_hot_standby as a deployment/capability fact; if it is unexpected, fix the binary, initdb, or database-creation process rather than trying SET.
OLAP	Not tunable. Use in_hot_standby to verify format, build, or resource assumptions on analytical nodes and keep every read/write candidate compatible.
Small nodes	Not tunable. Preserve it in inventory and incident reports; do not custom-build or rebuild merely to change it without a demonstrated compatibility need.

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: PG14–19 Beta 3 unmodified; OLAP: PG14–19 Beta 3 unmodified; CRIT: PG14–19 Beta 3 unmodified; TINY: PG14–19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

Common pitfalls

Trying to change read-only in_hot_standby with SET or a configuration file.
Assuming every cluster, database, or vendor build reports the same value.
Ignoring the value in file-format or feature-compatibility checks.
Treating reported metadata as a performance target instead of an environment fact.

hot_standby · max_standby_streaming_delay · hot_standby_feedback · primary_conninfo · block_size · data_checksums