init do
    `insert into users (id, age) values (1, 10)`
end

process do
    transaction tx1 read_committed do
        let t1_age := `select age from users where id = 1`
        `update users set age := $t1_age + 1 where id = 1`
    end
end

process do
    transaction tx2 read_committed do
        let t2_age := `select age from users where id = 1`
        `update users set age := $t2_age * 2 where id = 1`
    end
end

property eventually(`select age from users where id = 1` in {21, 22})