session_replication_role

session_replication_role is the PostgreSQL setting that defines the session’s behavior for triggers and rewrite rules.

Note

Fact — official short description: “Sets the session’s behavior for triggers and rewrite rules.”

Identity

Type , Valueenum: 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 , Valueorigin, replica, local: — for non-enum types
Category , ValueClient Connection Defaults / Statement Behavior: Upstream classification
Latest boot value , Valueorigin: origin

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	`origin`	—	origin

How it works

session_replication_role sets the session’s behavior for triggers and rewrite rules. replica suppresses ordinary triggers and rules, including foreign-key enforcement, and changing the value discards cached plans.

session_replication_role is a SUPERUSER-context setting. Superuser or a role granted the appropriate SET privilege can change it for a session, while ALTER ROLE or ALTER DATABASE can establish a default for future sessions.

Because session state can survive in pooled connections, role defaults, SET privilege, RESET behavior, and application checkout hooks are part of the control’s effective boundary.

Tuning advice

Tip

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

Workload	Guidance
OLTP	Do not tune session_replication_role. Only a controlled replication or repair process should set replica, and it must independently guarantee constraints and restore origin.
OLAP	Keep origin for analytical sessions; suppressing triggers does not accelerate reads and creates severe risk if the session writes.
Small nodes	Leave origin. The setting is not a small-node optimization and can bypass foreign keys.

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

Changing session_replication_role in one session and assuming role defaults, database defaults, or other pooled sessions changed with it.
Granting broad SET rights to a control that can change correctness, policy enforcement, or name resolution.
Failing to reset a security-sensitive session value before a pooled connection is reused by another request.
Forgetting that replica mode suppresses foreign-key triggers as well as application triggers.

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