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The following commit(s) were added to refs/heads/main by this push:
new 6b1a1cb81e fix: preserve state in
DistinctMedianAccumulator::evaluate() for window frame queries (#19887)
6b1a1cb81e is described below
commit 6b1a1cb81eb4b42b1d3d6fa9a695149407cc6348
Author: Kumar Ujjawal <[email protected]>
AuthorDate: Wed Jan 21 09:09:12 2026 +0530
fix: preserve state in DistinctMedianAccumulator::evaluate() for window
frame queries (#19887)
## Which issue does this PR close?
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We generally require a GitHub issue to be filed for all bug fixes and
enhancements and this helps us generate change logs for our releases.
You can link an issue to this PR using the GitHub syntax. For example
`Closes #123` indicates that this PR will close issue #123.
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- Closes #19612.
## Rationale for this change
The `DistinctMedianAccumulator::evaluate()` method was using
`std::mem::take()` which consumed the internal state, causing subsequent
calls to return incorrect results. This was the last remaining item from
#19612
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in the issue then this section is not needed.
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your changes and offer better suggestions for fixes.
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## What changes are included in this PR?
1. Changed `DistinctMedianAccumulator::evaluate()` to use `.iter()`
instead of `std::mem::take()` to preserve internal state across multiple
calls
2. Added sqllogictest case for distinct median with window frames
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is sometimes worth providing a summary of the individual changes in this
PR.
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## Are these changes tested?
Yes, added a sqllogictest
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## Are there any user-facing changes?
No
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---
datafusion/functions-aggregate/src/median.rs | 6 ++----
datafusion/sqllogictest/test_files/aggregate.slt | 26 ++++++++++++++++++++++++
2 files changed, 28 insertions(+), 4 deletions(-)
diff --git a/datafusion/functions-aggregate/src/median.rs
b/datafusion/functions-aggregate/src/median.rs
index f137ae0801..57cb14d7c1 100644
--- a/datafusion/functions-aggregate/src/median.rs
+++ b/datafusion/functions-aggregate/src/median.rs
@@ -566,10 +566,8 @@ impl<T: ArrowNumericType + Debug> Accumulator for
DistinctMedianAccumulator<T> {
}
fn evaluate(&mut self) -> Result<ScalarValue> {
- let mut d = std::mem::take(&mut self.distinct_values.values)
- .into_iter()
- .map(|v| v.0)
- .collect::<Vec<_>>();
+ let mut d: Vec<T::Native> =
+ self.distinct_values.values.iter().map(|v| v.0).collect();
let median = calculate_median::<T>(&mut d);
ScalarValue::new_primitive::<T>(median, &self.data_type)
}
diff --git a/datafusion/sqllogictest/test_files/aggregate.slt
b/datafusion/sqllogictest/test_files/aggregate.slt
index a5f3ef0413..be24178637 100644
--- a/datafusion/sqllogictest/test_files/aggregate.slt
+++ b/datafusion/sqllogictest/test_files/aggregate.slt
@@ -1226,6 +1226,32 @@ ORDER BY tags, timestamp;
4 tag2 90 67.5 82.5
5 tag2 100 70 90
+
+# Test distinct median non-sliding window
+query ITRR
+SELECT
+ timestamp,
+ tags,
+ value,
+ median(DISTINCT value) OVER (
+ PARTITION BY tags
+ ORDER BY timestamp
+ ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
+ ) AS distinct_median
+FROM median_window_test
+ORDER BY tags, timestamp;
+----
+1 tag1 10 10
+2 tag1 20 15
+3 tag1 30 20
+4 tag1 40 25
+5 tag1 50 30
+1 tag2 60 60
+2 tag2 70 65
+3 tag2 80 70
+4 tag2 90 75
+5 tag2 100 80
+
statement ok
DROP TABLE median_window_test;
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