backtrace_functions

backtrace_functions — Log backtrace for errors in these functions. Observed in PG13–19 Beta 3; its last measured boot default is empty string in PG19 Beta 3, with superuser context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA.

Note

Fact — official short description: “Log backtrace for errors in these functions.”

Identity

Type , Valuestring: 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 , Value—: — for non-enum types
Category , ValueDeveloper Options: Upstream classification
Latest boot value , Value"": empty string

Lifecycle

Fact	Value
First observed	PG13
Present in	PG13–19 Beta 3
Removed in	No
Introduction commit	`71a8a4f6e365` — Add backtrace support for error reporting
Commit date	2019-11-08
Discussion	thread 1 · thread 2

Default history

Measured PG9.0–19 Beta 3 boot defaults
Versions	Raw `boot_val`	Unit	Human value
PG13–19 Beta 3	`""`	—	empty string

How it works

backtrace_functions is a comma-separated list of internal C function names. If an error originates in a listed function, PostgreSQL appends a native backtrace to that error in the server log.

It matches C symbols, not SQL function names. Availability and symbol quality depend on platform, compiler, build flags, debug information, and whether functions were inlined.

The setting can target a narrow failure path without logging stacks for every error. Stack traces can expose implementation detail and increase log volume, so collection should be scoped and protected. Its superuser context permits an authorized session change without a server restart.

Tuning advice

Tip

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

Workload	Guidance
OLTP	Do not tune production OLTP with backtrace_functions. Enable it only for a bounded reproduction with an owner, log/disk budget, rollback condition, and evidence-capture plan; restore the default immediately afterward.
OLAP	Long analytical runs can amplify backtrace_functions’s debug overhead and artifacts. Prefer standard EXPLAIN and statistics first, and isolate any developer experiment from normal users.
Small nodes	Keep backtrace_functions at its upstream default. A small host has less spare CPU, disk, connection, and log capacity for developer instrumentation.

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: PG13–19 Beta 3 unmodified; OLAP: PG13–19 Beta 3 unmodified; CRIT: PG13–19 Beta 3 unmodified; TINY: PG13–19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

Common pitfalls

Leaving backtrace_functions enabled after the bounded diagnostic or recovery task.
Running the experiment on the only copy of production data.
Underestimating log, core-file, temporary-file, WAL, CPU, or connection-slot amplification.
Treating a server that merely starts or completes a query as proof that data and behavior are correct.

log_error_verbosity · log_min_error_statement · compute_query_id · log_line_prefix