Realtime Compute for Apache Flink：Window Top-N

新增、刪除window屬性欄位，該修改屬於完全相容變更。

-- 原始SQL。
select a, b, c, window_start from (
  select *,
      row_number() over (partition by b, window_start, window_end order by c) as rk
  from (
    select a,
      sum(b) as b,
      max(c) as c,
        window_start,
        window_end
    from table (tumble(table MyTable, descriptor(ts), interval '1' minute))
      group by a, window_start, window_end)
  ) where rk < 3;


-- 新增window end，該修改屬於完全相容變更。
select a, b, c, window_start, window_end from (
  select *,
      row_number() over (partition by b, window_start, window_end order by c) as rk
  from (
    select a,
      sum(b) as b,
      max(c) as c,
        window_start,
        window_end
    from table (tumble(table MyTable, descriptor(ts), interval '1' minute))
      group by a, window_start, window_end)
  ) where rk < 3;

是否輸出rank number的值，不影響相容性，該修改屬於完全相容變更。

-- 原始SQL。
select a, b, c, window_start from (
  select *,
      row_number() over (partition by b, window_start, window_end order by c) as rk
  from (
    select a,
      sum(b) as b,
      max(c) as c,
        window_start,
        window_end
    from table (tumble(table MyTable, descriptor(ts), interval '1' minute))
      group by a, window_start, window_end)
  ) where rk < 3;


-- 輸入rank number值：rk，該修改屬於完全相容變更。
select a, b, c, window_start, rk from (
  select *,
      row_number() over (partition by b, window_start, window_end order by c) as rk
  from (
    select a,
      sum(b) as b,
      max(c) as c,
        window_start,
        window_end
    from table (tumble(table MyTable, descriptor(ts), interval '1' minute))
      group by a, window_start, window_end)
  ) where rk < 3;

修改window相關屬性（window 的類型，window 的大小，時間相關屬性），該修改屬於不相容變更。

樣本可參見Window TVF修改window相關屬性樣本，詳情請參見不相容的變更。

新增、刪除、修改統計維度（group key）或者統計維度涉及欄位的計算邏輯發生變化，該修改屬於不相容變更。

樣本可參見Window TVF修改group key樣本，詳情請參見不相容的變更。

新增、刪除、修改統計指標，該修改屬於不相容變更。TOP-N的輸入發生變化，該修改屬於不相容變更。

-- 原始SQL。
select a, b, c, window_start from (
  select *,
      row_number() over (partition by b, window_start, window_end order by c) as rk
  from (
    select a,
      sum(b) as b,
      max(c) as c,
        window_start,
        window_end
    from table (tumble(table MyTable, descriptor(ts), interval '1' minute))
      group by a, window_start, window_end)
  ) where rk < 3;

-- 新增統計指標：min(d) as d，屬於不相容修改。
-- 該修改會導致TOP-N的輸入發生變化。
select a, b, c, d, window_start from (
  select *,
      row_number() over (partition by b, window_start, window_end order by c) as rk
  from (
    select a,
      sum(b) as b,
      max(c) as c,
      min(d) as d,
        window_start,
        window_end
    from table (tumble(table MyTable, descriptor(ts), interval '1' minute))
      group by a, window_start, window_end)
  ) where rk < 3;

新增、刪除、修改partition by key或者partition by key涉及欄位的計算邏輯發生變化，該修改屬於不相容變更。

樣本可參見Top N修改partition by key樣本，詳情請參見不相容的變更。

修改order by相關屬性（排序欄位和方向），該修改屬於不相容修改。

樣本可參見Top N修改order by key樣本，詳情請參見不相容的變更。

修改rank range的值（Top N中N 的值），則該修改屬於不相容修改。

樣本可參見Top N修改rank range樣本，詳情請參見不相容的變更。