tsm_system_time

TABLESAMPLE method which accepts time in milliseconds as a limit

tsm_system_time : TABLESAMPLE method which accepts time in milliseconds as a limit

Overview

ID	Extension	Package	Version	Category	License	Language
4890	tsm_system_time	tsm_system_time	`1.0`	FUNC	PostgreSQL	C

Attribute	Has Binary	Has Library	Need Load	Has DDL	Relocatable	Trusted
--s-dt-	No	Yes	No	Yes	no	yes

Relationships
See Also	faker dbt2 random tsm_system_rows pg_mockable pgsqlmock pgtap omni_test

Packages

PG18	PG17	PG16	PG15	PG14
1.0	1.0	1.0	1.0	1.0

This is a built-in contrib extension ship with the PostgreSQL kernel

Install

Create this extension with:

CREATE EXTENSION tsm_system_time;

Usage

tsm_system_time: time-based TABLESAMPLE method

Provides the SYSTEM_TIME table sampling method that returns as many rows as can be read within a specified time limit.

CREATE EXTENSION tsm_system_time;

TABLESAMPLE Method

SYSTEM_TIME(milliseconds float) – maximum time to spend reading the table.

Examples

-- Sample rows readable within 1 second
SELECT * FROM my_table TABLESAMPLE SYSTEM_TIME(1000);

-- Sample from a large table with a 500ms budget
SELECT count(*) FROM large_table TABLESAMPLE SYSTEM_TIME(500);

Performs block-level sampling (not row-level). If the entire table can be read within the time limit, all rows are returned. Does not support REPEATABLE.