gin_fuzzy_search_limit

gin_fuzzy_search_limit is the PostgreSQL setting that defines the maximum allowed result for exact search by GIN.

Note

Fact — official short description: “Sets the maximum allowed result for exact search by GIN.”

Identity

Type , Valueinteger: Upstream pg_settings type
Context , Valueuser: Settable by an ordinary user
Unit , Value—: Raw unit
Range , Value0 – 2147483647: Raw limits in the last observed version
Enum values , Value—: — for non-enum types
Category , ValueClient Connection Defaults / Other Defaults: Upstream classification
Latest boot value , Value0: 0

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	`0`	—	0

How it works

gin_fuzzy_search_limit sets the maximum allowed result for exact search by GIN. 0 means no limit. A positive limit makes broad GIN searches return a randomly chosen subset of matches, trading completeness for bounded work; zero preserves exact results.

gin_fuzzy_search_limit 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.

GIN behavior also depends on per-index storage parameters, work or maintenance memory, autovacuum, and the shape of indexed values and predicates.

Tuning advice

Tip

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

Workload	Guidance
OLTP	Change gin_fuzzy_search_limit only after measuring the affected GIN maintenance or search path. Prefer an index-level override when one index, rather than the whole cluster, is exceptional.
OLAP	For batch loads or broad searches, test gin_fuzzy_search_limit against ingestion latency, cleanup spikes, result completeness, and maintenance windows.
Small nodes	Do not raise gin_fuzzy_search_limit merely because the default is reached; bound memory and I/O bursts, and keep exact-query semantics unless approximation is explicitly acceptable.

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 gin_fuzzy_search_limit in one session and assuming role defaults, database defaults, or other pooled sessions changed with it.
Applying a cluster-wide GIN value to fix one exceptional index instead of using its storage parameters.
Ignoring cleanup latency, I/O bursts, autovacuum interaction, or result completeness while tuning.
Enabling a positive limit without telling callers that exact searches may return an incomplete random subset.

gin_pending_list_limit · maintenance_work_mem · work_mem · vacuum_cleanup_index_scale_factor · autovacuum_work_mem