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fix null count stats computation #18276

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Merged
merged 2 commits into from
Oct 25, 2025
+35 −7
Merged

fix null count stats computation #18276

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58469d9
fix null count stats computation
adriangb Oct 24, 2025
75471c0
add test
adriangb Oct 24, 2025
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15 changes: 8 additions & 7 deletions datafusion/datasource-parquet/src/metadata.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -299,7 +299,6 @@ impl<'a> DFParquetMetadata<'a> {
summarize_min_max_null_counts(
&mut accumulators,
idx,
num_rows,
&stats_converter,
row_groups_metadata,
)
Expand Down Expand Up @@ -417,7 +416,6 @@ struct StatisticsAccumulators<'a> {
fn summarize_min_max_null_counts(
accumulators: &mut StatisticsAccumulators,
arrow_schema_index: usize,
num_rows: usize,
stats_converter: &StatisticsConverter,
row_groups_metadata: &[RowGroupMetaData],
) -> Result<()> {
Expand Down Expand Up @@ -449,11 +447,14 @@ fn summarize_min_max_null_counts(
);
}

accumulators.null_counts_array[arrow_schema_index] =
Precision::Exact(match sum(&null_counts) {
Some(null_count) => null_count as usize,
None => num_rows,
});
accumulators.null_counts_array[arrow_schema_index] = match sum(&null_counts) {
Some(null_count) => Precision::Exact(null_count as usize),
None => match null_counts.len() {
// If sum() returned None we either have no rows or all values are null
0 => Precision::Exact(0),
_ => Precision::Absent,
},
};

Ok(())
}
Expand Down
27 changes: 27 additions & 0 deletions datafusion/sqllogictest/test_files/parquet.slt
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Expand Up @@ -862,3 +862,30 @@ select part, k, v from t order by k

statement ok
DROP TABLE t;

# Regression test for files with stats on some columns and not others
# See https://github.com/apache/datafusion/pull/18276

query I
COPY (SELECT 1::int AS a, 2::int as b)
TO 'test_files/scratch/parquet/mixed_stats.parquet'
STORED AS PARQUET OPTIONS (
'STATISTICS_ENABLED::b' 'none'
);
----
1

statement ok
CREATE EXTERNAL TABLE t
STORED AS PARQUET
LOCATION 'test_files/scratch/parquet/mixed_stats.parquet';

query I
SELECT b
FROM t
WHERE b = 2;
----
2
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@adriangb adriangb Oct 24, 2025

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On main this outputs 0 rows:

❯ datafusion-cli -f q.sql
DataFusion CLI v50.0.0
+-------+
| count |
+-------+
| 1     |
+-------+
1 row(s) fetched. 
Elapsed 0.002 seconds.

0 row(s) fetched. 
Elapsed 0.001 seconds.

+---+
| b |
+---+
+---+
0 row(s) fetched. 
Elapsed 0.003 seconds.


statement ok
DROP TABLE t;