Parsed test spec with 2 sessions

starting permutation: w1_fetch_and_mark w2_fetch_pending w1_commit w2_commit
step w1_fetch_and_mark: 
    WITH fetched AS (
        SELECT id FROM ulak.queue
        WHERE status = 'pending'
        ORDER BY id LIMIT 3
        FOR UPDATE SKIP LOCKED
    ),
    updated AS (
        UPDATE ulak.queue
        SET status = 'processing', processing_started_at = NOW()
        WHERE id IN (SELECT id FROM fetched)
        RETURNING payload::text, status
    )
    SELECT * FROM updated ORDER BY payload;

payload   |status    
----------+----------
{"seq": 1}|processing
{"seq": 2}|processing
{"seq": 3}|processing
(3 rows)

step w2_fetch_pending: 
    SELECT payload::text, status
    FROM ulak.queue
    WHERE status = 'pending'
    ORDER BY id
    FOR UPDATE SKIP LOCKED;

payload   |status 
----------+-------
{"seq": 4}|pending
{"seq": 5}|pending
{"seq": 6}|pending
(3 rows)

step w1_commit: COMMIT;
step w2_commit: COMMIT;

starting permutation: w1_fetch_and_mark w2_fetch_pending w2_commit w1_commit
step w1_fetch_and_mark: 
    WITH fetched AS (
        SELECT id FROM ulak.queue
        WHERE status = 'pending'
        ORDER BY id LIMIT 3
        FOR UPDATE SKIP LOCKED
    ),
    updated AS (
        UPDATE ulak.queue
        SET status = 'processing', processing_started_at = NOW()
        WHERE id IN (SELECT id FROM fetched)
        RETURNING payload::text, status
    )
    SELECT * FROM updated ORDER BY payload;

payload   |status    
----------+----------
{"seq": 1}|processing
{"seq": 2}|processing
{"seq": 3}|processing
(3 rows)

step w2_fetch_pending: 
    SELECT payload::text, status
    FROM ulak.queue
    WHERE status = 'pending'
    ORDER BY id
    FOR UPDATE SKIP LOCKED;

payload   |status 
----------+-------
{"seq": 4}|pending
{"seq": 5}|pending
{"seq": 6}|pending
(3 rows)

step w2_commit: COMMIT;
step w1_commit: COMMIT;