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--
-- Free Space Map test
--
CREATE TABLE fsm_check_size (num int, str text);
-- With one block, there should be no FSM
INSERT INTO fsm_check_size VALUES(1, 'a');
VACUUM fsm_check_size;
SELECT pg_relation_size('fsm_check_size', 'main') AS heap_size,
pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
heap_size | fsm_size
-----------+----------
8192 | 0
(1 row)
-- Extend table with enough blocks to exceed the FSM threshold
DO $$
DECLARE curtid tid;
num int;
BEGIN
num = 11;
LOOP
INSERT INTO fsm_check_size VALUES (num, 'b') RETURNING ctid INTO curtid;
EXIT WHEN curtid >= tid '(4, 0)';
num = num + 1;
END LOOP;
END;
$$;
VACUUM fsm_check_size;
SELECT pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
fsm_size
----------
24576
(1 row)
-- Add long random string to extend TOAST table to 1 block
INSERT INTO fsm_check_size
VALUES(0, (SELECT string_agg(md5(chr(i)), '')
FROM generate_series(1,100) i));
VACUUM fsm_check_size;
SELECT pg_relation_size(reltoastrelid, 'main') AS toast_size,
pg_relation_size(reltoastrelid, 'fsm') AS toast_fsm_size
FROM pg_class WHERE relname = 'fsm_check_size';
toast_size | toast_fsm_size
------------+----------------
8192 | 0
(1 row)
DROP TABLE fsm_check_size;
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