fix: handle remaining buf

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>

src/query/src/part_sort.rs

@@ -869,8 +869,16 @@ impl PartSortStream {
 
         // If we've processed all partitions, mark completion.
         if self.cur_part_idx >= self.partition_ranges.len() {
-            debug_assert!(remaining_range.num_rows() == 0);
+            // If there is remaining data here, it means the input data doesn't match the
+            // provided `PartitionRange`s (e.g. out-of-order input or mismatched ranges).
+            // In release builds, the previous `debug_assert!` would silently drop data and
+            // could lead to incorrect empty results. To keep query correctness, fall back
+            // to consuming the remaining data as part of the last range.
+            if remaining_range.num_rows() != 0 {
+                self.push_buffer(remaining_range)?;
+            }
             self.input_complete = true;
+            self.evaluating_batch = None;
             return Ok(());
         }
 
@@ -937,7 +945,12 @@ impl PartSortStream {
         // If we've processed all partitions, sort and output
         if self.cur_part_idx >= self.partition_ranges.len() {
             // assert there is no data beyond the last partition range (remaining is empty).
-            debug_assert!(remaining_range.num_rows() == 0);
+            // Similar to the TopK path, do not silently drop remaining data in release builds.
+            // If this happens, the input stream doesn't match `PartitionRange`s; include the
+            // remaining data for correctness.
+            if remaining_range.num_rows() != 0 {
+                self.push_buffer(remaining_range)?;
+            }
 
             // Sort and output the final group
             return self.sorted_buffer_if_non_empty();
@@ -999,11 +1012,11 @@ impl PartSortStream {
             {
                 // Check if we've already processed all partitions
                 if self.cur_part_idx >= self.partition_ranges.len() {
-                    // All partitions processed, discard remaining data
-                    if let Some(sorted_batch) = self.sorted_buffer_if_non_empty()? {
-                        return Poll::Ready(Some(Ok(sorted_batch)));
-                    }
-                    return Poll::Ready(None);
+                    // All partitions processed but we still have remaining data in-flight.
+                    // Don't discard it, otherwise we may incorrectly return an empty result.
+                    self.push_buffer(evaluating_batch)?;
+                    self.input_complete = true;
+                    continue;
                 }
 
                 if let Some(sorted_batch) = self.split_batch(evaluating_batch)? {
@@ -1431,6 +1444,47 @@ mod test {
         }
     }
 
+    #[tokio::test]
+    async fn topk_does_not_silently_drop_out_of_range_data() {
+        let unit = TimeUnit::Millisecond;
+        let schema = Arc::new(Schema::new(vec![Field::new(
+            "ts",
+            DataType::Timestamp(unit, None),
+            false,
+        )]));
+
+        // The input data is outside the provided PartitionRange.
+        // Historically this could lead to an empty result in release builds due to
+        // `debug_assert!`-only checks dropping the remaining batch.
+        let input_ranged_data = vec![(
+            PartitionRange {
+                start: Timestamp::new(0, common_time::timestamp::TimeUnit::from(&unit)),
+                end: Timestamp::new(10, common_time::timestamp::TimeUnit::from(&unit)),
+                num_rows: 1,
+                identifier: 0,
+            },
+            vec![
+                DfRecordBatch::try_new(schema.clone(), vec![new_ts_array(unit, vec![100])])
+                    .unwrap(),
+            ],
+        )];
+
+        let expected_output = Some(
+            DfRecordBatch::try_new(schema.clone(), vec![new_ts_array(unit, vec![100])]).unwrap(),
+        );
+
+        run_test(
+            0,
+            input_ranged_data,
+            schema,
+            SortOptions::default(),
+            Some(10),
+            expected_output,
+            None,
+        )
+        .await;
+    }
+
     #[allow(clippy::print_stdout)]
     async fn run_test(
         case_id: usize,