Unexpected analytic function output in common table expression - sql-server

Question

In SQL Server 2019, analytic functions are not returning the results that I would expect in the context of recursive common table expressions. Consider the following non-recursive T-SQL query:
WITH SourceData (RowNum, Uniform, RowVal) AS (
SELECT 1, 'A', 'A' UNION ALL
SELECT 2, 'A', 'B' UNION ALL
SELECT 3, 'A', 'C' UNION ALL
SELECT 4, 'A', 'D'
),
RecursiveCte0 (RowNum, Uniform, RowVal, MinVal, SomeSum, RowNumCalc, RecursiveLevel) AS (
SELECT RowNum, Uniform, RowVal, RowVal, RowNum, CAST(RowNum AS BIGINT), 0
FROM SourceData
),
RecursiveCte1 (RowNum, Uniform, RowVal, MinVal, SomeSum, RowNumCalc, RecursiveLevel) AS (
SELECT * FROM RecursiveCte0
UNION ALL
SELECT
RowNum, Uniform, RowVal,
MIN(MinVal) OVER (PARTITION BY Uniform),
SUM(RowNum) OVER (PARTITION BY Uniform),
ROW_NUMBER() OVER (PARTITION BY Uniform ORDER BY RowNum),
RecursiveLevel + 1
FROM RecursiveCte0
)
SELECT *
FROM RecursiveCte1
ORDER BY RecursiveLevel, RowNum;
Results:
RowNum Uniform RowVal MinVal SomeSum RowNumCalc RecursiveLevel
1 A A A 1 1 0
2 A B B 2 2 0
3 A C C 3 3 0
4 A D D 4 4 0
1 A A A 10 1 1
2 A B A 10 2 1
3 A C A 10 3 1
4 A D A 10 4 1
As expected, the MIN, SUM, and ROW_NUMBER functions generate the appropriate values based on all rows from RecursiveCte0. I would expect the following recursive query to be logically identical to the non-recursive version above, but it produces different results:
WITH SourceData (RowNum, Uniform, RowVal) AS (
SELECT 1, 'A', 'A' UNION ALL
SELECT 2, 'A', 'B' UNION ALL
SELECT 3, 'A', 'C' UNION ALL
SELECT 4, 'A', 'D'
),
RecursiveCte (RowNum, Uniform, RowVal, MinVal, SomeSum, RowNumCalc, RecursiveLevel) AS (
SELECT RowNum, Uniform, RowVal, RowVal, RowNum, CAST(RowNum AS BIGINT), 0
FROM SourceData
UNION ALL
SELECT
RowNum, Uniform, RowVal,
MIN(MinVal) OVER (PARTITION BY Uniform),
SUM(RowNum) OVER (PARTITION BY Uniform),
ROW_NUMBER() OVER (PARTITION BY Uniform ORDER BY RowNum),
RecursiveLevel + 1
FROM RecursiveCte
WHERE RecursiveLevel < 1
)
SELECT *
FROM RecursiveCte
ORDER BY RecursiveLevel, RowNum;
Results:
RowNum Uniform RowVal MinVal SomeSum RowNumCalc RecursiveLevel
1 A A A 1 1 0
2 A B B 2 2 0
3 A C C 3 3 0
4 A D D 4 4 0
1 A A A 1 1 1
2 A B B 2 1 1
3 A C C 3 1 1
4 A D D 4 1 1
For each of the three analytic functions, it appears that the grouping is only being applied within the context of each individual row, rather than all of the rows at that level. This unexpected behavior also happens if I partition over (SELECT NULL). I would expect the analytic functions to apply to the entire recursion level, as per MSDN:
Analytic and aggregate functions in the recursive part of the CTE are
applied to the set for the current recursion level and not to the set
for the CTE. Functions like ROW_NUMBER operate only on the subset of
data passed to them by the current recursion level and not the entire
set of data passed to the recursive part of the CTE.
Why do these two queries produce different results? Is there a way to effectively use analytic functions with recursive common table expressions?