compute_query_id

compute_query_id — Enables in-core computation of query identifiers. Observed in PG14–19 Beta 3; its last measured boot default is auto 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: “Enables in-core computation of query identifiers.”

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 , Valueauto, regress, on, off: — for non-enum types
Category , ValueStatistics / Monitoring: Upstream classification
Latest boot value , Valueauto: auto

Lifecycle

Fact	Value
First observed	PG14
Present in	PG14–19 Beta 3
Removed in	No
Introduction commit	`5fd9dfa5f50e` — Move pg_stat_statements query jumbling to core.
Commit date	2021-04-07
Discussion	thread 1

Default history

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

How it works

compute_query_id controls PostgreSQL’s in-core normalized query identifier. The identifier can appear in pg_stat_activity, EXPLAIN, and logs, and is required by pg_stat_statements unless another module computes one.

auto lets a module request in-core computation, on always computes, off prevents it, and regress behaves like auto while suppressing the ID in EXPLAIN for stable regression output.

Only one provider should compute the identifier. An extension with an alternative algorithm must disable the in-core implementation and detect conflicts rather than silently publishing two incompatible IDs. 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	Use auto when pg_stat_statements or another module should request the in-core identifier, and use on only when logs, EXPLAIN, or monitoring require IDs without such a module. Measure query-normalization overhead at peak parse/plan rates.
OLAP	auto or on can make long analytical statements easier to correlate across pg_stat_activity, EXPLAIN, and logs. The cost is query-tree normalization and hashing, not clock reads; compare planning CPU on workloads with very large statements.
Small nodes	Keep auto unless an external query-ID provider requires off. regress is for stable regression output, not a smaller production setting, and off can remove IDs required by pg_stat_statements.

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

Enabling the in-core provider while an extension also attempts to compute a different query identifier.
Setting off and silently losing IDs required by pg_stat_statements, logs, or correlation tooling.
Treating regress as a production optimization rather than a test-output mode.
Using query IDs as stable cross-major-version or cryptographic identifiers.

track_activities · shared_preload_libraries · log_line_prefix · track_activity_query_size