log_planner_stats

log_planner_stats — Writes planner performance statistics to the server log. Observed in PG9.0–19 Beta 3; its last measured boot default is off 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: “Writes planner performance statistics to the server log.”

Identity

Type , Valuebool: 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 , ValueStatistics / Monitoring: Upstream classification
Latest boot value , Valueoff: off

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	`off`	—	off

How it works

log_planner_stats emits planner-stage resource usage for every query using a crude getrusage-style profiler. Output goes to the server log and is intended for short diagnostic sessions.

log_statement_stats reports the total statement, while parser, planner, and executor switches report individual phases. The total switch cannot be enabled together with any per-phase switch.

This is synchronous diagnostic logging rather than the cumulative statistics system. Volume and formatting make it unsuitable as routine production telemetry. 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 enable log_planner_stats as normal OLTP tuning. Use it briefly on an isolated reproduction or one controlled session, collect the needed log, then disable it.
OLAP	For a specific analytical statement, EXPLAIN (ANALYZE, BUFFERS) and cumulative views are usually more actionable than cluster-wide log_planner_stats. Scope any use and budget log volume.
Small nodes	Leave log_planner_stats=off. A small host is especially vulnerable to diagnostic log I/O and storage exhaustion.

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

Enabling or enlarging log_planner_stats without measuring collection and observation overhead.
Confusing collection semantics with a performance-control or I/O-control setting.
Assuming all statistics are immediately current inside a long transaction.
Collecting sensitive query text or identifiers without matching access and retention policy.

log_statement_stats · log_parser_stats · log_executor_stats · log_min_duration_statement · join_collapse_limit