src/test/singlenode_isolation2/output/uao/vacuum_self_function.source

-- @Description Test scenario where a backend accesses AO table with a snapshot
-- that was acquired before vacuum.
--
DROP TABLE IF EXISTS ao;
DROP
CREATE TABLE ao (a INT, b INT) USING @amname@;
CREATE
INSERT INTO ao SELECT i as a, i as b FROM generate_series(1, 100) AS i;
INSERT 100

DELETE FROM ao WHERE a <= 30;
DELETE 30

create or replace function myfunc() returns bigint as $$ begin  /* inside a function */ perform pg_sleep(10); /* inside a function */ return (select count(*) from ao);  /* inside a function */ end;  /* inside a function */ $$ stable language plpgsql;
CREATE

-- Launch function into the background.
1&: select myfunc();  <waiting ...>

-- Meanwhile, DELETE some rows and VACUUM. VACUUM should not recycle the
-- old tuple versions that are still needed by the function later. It will
-- compact the segfile, but keep the old segfile in AWAITING_DROP state.
2: DELETE FROM ao WHERE a <= 50;
DELETE 20
2: SELECT segno, tupcount, state FROM gp_ao_or_aocs_seg('ao');
 segno | tupcount | state 
-------+----------+-------
 0     | 100      | 1     
(1 row)
2: VACUUM ao;
VACUUM
2: SELECT segno, tupcount, state FROM gp_ao_or_aocs_seg('ao');
 segno | tupcount | state 
-------+----------+-------
 0     | 100      | 2     
 1     | 50       | 1     
(2 rows)

-- A second VACUUM shouldn't recycle them either.
2: VACUUM ao;
VACUUM
2: SELECT segno, tupcount, state FROM gp_ao_or_aocs_seg('ao');
 segno | tupcount | state 
-------+----------+-------
 0     | 100      | 2     
 1     | 50       | 1     
(2 rows)
1<:  <... completed>
 myfunc 
--------
 70     
(1 row)

-- Now that the first transaction has finished, VACUUM can recycle.
2: VACUUM ao;
VACUUM
2: SELECT segno, tupcount, state FROM gp_ao_or_aocs_seg('ao');
 segno | tupcount | state 
-------+----------+-------
 0     | 0        | 1     
 1     | 50       | 1     
(2 rows)