temp_buffers

A per-session, lazily allocated buffer ceiling used only when accessing temporary tables.

Note

Fact — official short description: “Sets the maximum number of temporary buffers used by each session.”

Identity

Type , Valueinteger: Upstream pg_settings type
Context , Valueuser: Settable by an ordinary user
Unit , Value8kB: Raw unit
Range , Value100 – 1073741823: Raw limits in the last observed version
Enum values , Value—: — for non-enum types
Category , ValueResource Usage / Memory: Upstream classification
Latest boot value , Value1024: 8 MiB (1024 × 8kB)

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	`1024`	`8kB`	8 MiB (1024 × 8kB)

How it works

temp_buffers controls session-local buffers for temporary-table access. It does not govern sort or hash spill files created by ordinary query execution.

A session can change the value only before its first use of a temporary table; later SET commands have no effect for that session. Buffers are allocated on demand up to the ceiling.

An unused increase still creates buffer-descriptor overhead, while each buffer actually used consumes one database block, normally 8kB. Aggregate usage therefore depends on the number of sessions actively using temporary tables.

Tuning advice

Tip

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

Workload	Guidance
OLTP	Leave the default unless the application demonstrably uses sizable temporary tables. Prefer scoped changes in the sessions that create them and set the value before first access.
OLAP	Raise it only for workflows that use PostgreSQL temporary tables; work_mem, not temp_buffers, is the primary control for sort and hash operations. Include session concurrency in the budget.
Small nodes	Keep the default and avoid globally increasing per-session ceilings. Temporary-table-heavy jobs should be isolated or adjusted locally.

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

Confusing temporary-table buffers with sort and hash temporary files.
Issuing SET after the session has already accessed a temporary table.
Ignoring multiplication across many sessions actively using temporary tables.
Assuming a large value is fully allocated immediately; PostgreSQL grows usage on demand, though descriptor overhead remains.

work_mem · temp_file_limit · temp_tablespaces · max_connections · log_temp_files