CREATE EXTENSION tsm_system_rows;
CREATE TABLE test_tablesample (id int, name text) WITH (fillfactor=10); -- force smaller pages so we don't have to load too much data to get multiple pages
INSERT INTO test_tablesample SELECT i, repeat(i::text, 1000) FROM generate_series(0, 30) s(i) ORDER BY i;
ANALYZE test_tablesample;
SELECT count(*) FROM test_tablesample TABLESAMPLE system_rows (1000);
 count 
-------
    31
(1 row)

SELECT id FROM test_tablesample TABLESAMPLE system_rows (8) REPEATABLE (5432);
 id 
----
  7
 14
 21
 28
  4
 11
 18
 25
(8 rows)

EXPLAIN SELECT id FROM test_tablesample TABLESAMPLE system_rows (20) REPEATABLE (10);
                                    QUERY PLAN                                     
-----------------------------------------------------------------------------------
 Sample Scan (system_rows) on test_tablesample  (cost=0.00..80.20 rows=20 width=4)
(1 row)

-- done
DROP TABLE test_tablesample CASCADE;