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Sliding window min() returns stale value when all non-NULL values leave the frame #23872
Description
Describe the bug
SlidingMinAccumulator reports a stale minimum when every non-NULL value has been retracted from the window but the frame is still non-empty (i.e., the frame contains only NULLs). Sliding max is correct.
To Reproduce
SELECT id, x,
MIN(x) OVER (ORDER BY id ROWS BETWEEN 1 PRECEDING AND CURRENT ROW) AS min_x
FROM (VALUES (1, 3), (2, NULL), (3, NULL)) t(id, x)
ORDER BY id;
==>
+----+------+-------+
| id | x | min_x |
+----+------+-------+
| 1 | 3 | 3 |
| 2 | NULL | 3 |
| 3 | NULL | 3 |
+----+------+-------+
Expected behavior
Postgres and DuckDB both return the expected results:
+----+------+-------+
| id | x | min_x |
+----+------+-------+
| 1 | 3 | 3 |
| 2 | NULL | 3 |
| 3 | NULL | NULL |
+----+------+-------+
Additional context
No response
Activity
neilconway commentedon Jul 24, 2026
take
fix: sliding window `min()` returns wrong value for all-NULL windows (a…
fix: sliding window `min()` returns wrong value for all-NULL windows (a…