tcp_user_timeout

tcp_user_timeout is the PostgreSQL setting that defines the TCP user timeout.

Note

Fact — official short description: “TCP user timeout.”

Identity

Type , Valueinteger: Upstream pg_settings type
Context , Valueuser: Settable by an ordinary user
Unit , Valuems: Raw unit
Range , Value0 – 2147483647: Raw limits in the last observed version
Enum values , Value—: — for non-enum types
Category , ValueConnections and Authentication / TCP Settings: Upstream classification
Latest boot value , Value0: 0 ms

Lifecycle

Fact	Value
First observed	PG12
Present in	PG12–19 Beta 3
Removed in	No
Introduction commit	`249d64999615` — Add support TCP user timeout in libpq and the backend server
Commit date	2019-04-06
Discussion	thread 1

Default history

Measured PG9.0–19 Beta 3 boot defaults
Versions	Raw `boot_val`	Unit	Human value
PG12–19 Beta 3	`0`	`ms`	0 ms

How it works

tcp_user_timeout sets the TCP user timeout. 0 means use the system default. Where supported, it bounds how long transmitted data may remain unacknowledged before TCP closes the connection; it is distinct from keepalive probing of an idle connection.

tcp_user_timeout is a USER-context setting. An authorized role can change it for a session, while ALTER ROLE or ALTER DATABASE can establish a default for future sessions.

Timeouts overlap: the first applicable deadline wins, while client, pooler, TCP, and server cancellation behavior determines whether work is retried, canceled, or the session is closed.

Tuning advice

Tip

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

Workload	Guidance
OLTP	Set tcp_user_timeout from the maximum acceptable unacknowledged-data stall, below the service failover budget and with client retry behavior tested.
OLAP	Allow for temporary congestion during large result transfer, but keep the value below the point where an unreachable peer wastes a worker for the rest of the job window.
Small nodes	Use the operating-system default unless measured half-open connections require a bound; confirm platform support before relying on it.

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: PG12–19 Beta 3 unmodified; OLAP: PG12–19 Beta 3 unmodified; CRIT: PG12–19 Beta 3 unmodified; TINY: PG12–19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

Common pitfalls

Changing tcp_user_timeout in one session and assuming role defaults, database defaults, or other pooled sessions changed with it.
Forgetting that zero usually disables the timeout or delegates behavior to the operating system.
Setting overlapping deadlines without deciding which layer owns retries, cancellation, and connection disposal.
Confusing unacknowledged-data timeout with keepalive detection for an otherwise idle socket.

tcp_keepalives_idle · tcp_keepalives_interval · tcp_keepalives_count · client_connection_check_interval · authentication_timeout