tsm_system_rows

TABLESAMPLE method which accepts number of rows as a limit

https://www.postgresql.org/docs/current/tsm-system-rows.html

Overview

Package	Version	Category	License	Language
`tsm_system_rows`	`1.0`	FUNC	PostgreSQL	C

ID	Extension	Bin	Lib	Load	Create	Trust	Reloc	Schema
4910	`tsm_system_rows`	No	Yes	No	Yes	Yes	No	-

Related	`faker` `dbt2` `random` `tsm_system_time` `pg_mockable` `pgsqlmock` `pgtap` `omni_test`
Depended By	`documentdb`

Version

PG18	PG17	PG16	PG15	PG14
1.0	1.0	1.0	1.0	1.0

Install

Note: This is a built-in contrib extension of PostgreSQL

CREATE EXTENSION tsm_system_rows;

Usage

tsm_system_rows: row-count-based TABLESAMPLE method

Provides the SYSTEM_ROWS table sampling method that returns exactly the specified number of rows.

CREATE EXTENSION tsm_system_rows;

TABLESAMPLE Method

SYSTEM_ROWS(count int) – maximum number of rows to return.

Examples

-- Sample exactly 100 rows
SELECT * FROM my_table TABLESAMPLE SYSTEM_ROWS(100);

-- Quick peek at 10 rows from a large table
SELECT * FROM large_table TABLESAMPLE SYSTEM_ROWS(10);

Performs block-level sampling (may exhibit clustering effects with small samples). Returns all rows if the table has fewer rows than requested. Does not support REPEATABLE.