Set projection before configuring the source

datafusion/core/src/datasource/file_format/parquet.rs

@@ -1934,6 +1934,7 @@ mod tests {
 
         // test metadata
         assert_eq!(exec.statistics()?.num_rows, Precision::Exact(8));
+        // TODO correct byte size: https://github.com/apache/datafusion/issues/14936
         assert_eq!(exec.statistics()?.total_byte_size, Precision::Exact(671));
 
         Ok(())
@@ -1976,6 +1977,7 @@ mod tests {
 
         // note: even if the limit is set, the executor rounds up to the batch size
         assert_eq!(exec.statistics()?.num_rows, Precision::Exact(8));
+        // TODO correct byte size: https://github.com/apache/datafusion/issues/14936
         assert_eq!(exec.statistics()?.total_byte_size, Precision::Exact(671));
         let batches = collect(exec, task_ctx).await?;
         assert_eq!(1, batches.len());

datafusion/core/src/datasource/listing/table.rs

@@ -1239,6 +1239,7 @@ mod tests {
 
         let exec = table.scan(&state, None, &[], None).await?;
         assert_eq!(exec.statistics()?.num_rows, Precision::Exact(8));
+        // TODO correct byte size: https://github.com/apache/datafusion/issues/14936
         assert_eq!(exec.statistics()?.total_byte_size, Precision::Exact(671));
 
         Ok(())

datafusion/core/tests/parquet/file_statistics.rs

@@ -82,7 +82,8 @@ async fn load_table_stats_with_session_level_cache() {
     assert_eq!(exec1.statistics().unwrap().num_rows, Precision::Exact(8));
     assert_eq!(
         exec1.statistics().unwrap().total_byte_size,
-        Precision::Exact(671)
+        // TODO correct byte size: https://github.com/apache/datafusion/issues/14936
+        Precision::Exact(671),
     );
     assert_eq!(get_static_cache_size(&state1), 1);
 
@@ -93,7 +94,8 @@ async fn load_table_stats_with_session_level_cache() {
     assert_eq!(exec2.statistics().unwrap().num_rows, Precision::Exact(8));
     assert_eq!(
         exec2.statistics().unwrap().total_byte_size,
-        Precision::Exact(671)
+        // TODO correct byte size: https://github.com/apache/datafusion/issues/14936
+        Precision::Exact(671),
     );
     assert_eq!(get_static_cache_size(&state2), 1);
 
@@ -104,7 +106,8 @@ async fn load_table_stats_with_session_level_cache() {
     assert_eq!(exec3.statistics().unwrap().num_rows, Precision::Exact(8));
     assert_eq!(
         exec3.statistics().unwrap().total_byte_size,
-        Precision::Exact(671)
+        // TODO correct byte size: https://github.com/apache/datafusion/issues/14936
+        Precision::Exact(671),
     );
     // List same file no increase
     assert_eq!(get_static_cache_size(&state1), 1);

datafusion/datasource/src/file_scan_config.rs

@@ -31,9 +31,7 @@ use arrow::{
     buffer::Buffer,
     datatypes::{ArrowNativeType, DataType, Field, Schema, SchemaRef, UInt16Type},
 };
-use datafusion_common::{
-    exec_err, stats::Precision, ColumnStatistics, Constraints, Result, Statistics,
-};
+use datafusion_common::{exec_err, ColumnStatistics, Constraints, Result, Statistics};
 use datafusion_common::{DataFusionError, ScalarValue};
 use datafusion_execution::{
     object_store::ObjectStoreUrl, SendableRecordBatchStream, TaskContext,
@@ -86,20 +84,22 @@ use crate::{
 /// #  Field::new("c4", DataType::Int32, false),
 /// # ]));
 /// # // Note: crate mock ParquetSource, as ParquetSource is not in the datasource crate
-/// # struct ParquetSource {};
+/// # struct ParquetSource {
+/// #    projected_statistics: Option<Statistics>
+/// # };
 /// # impl FileSource for ParquetSource {
 /// #  fn create_file_opener(&self, _: Arc<dyn ObjectStore>, _: &FileScanConfig, _: usize) -> Arc<dyn FileOpener> { unimplemented!() }
 /// #  fn as_any(&self) -> &dyn Any { self  }
 /// #  fn with_batch_size(&self, _: usize) -> Arc<dyn FileSource> { unimplemented!() }
 /// #  fn with_schema(&self, _: SchemaRef) -> Arc<dyn FileSource> { unimplemented!() }
 /// #  fn with_projection(&self, _: &FileScanConfig) -> Arc<dyn FileSource> { unimplemented!() }
-/// #  fn with_statistics(&self, _: Statistics) -> Arc<dyn FileSource> { Arc::new(Self::new()) }
+/// #  fn with_statistics(&self, statistics: Statistics) -> Arc<dyn FileSource> { Arc::new(Self {projected_statistics: Some(statistics)} ) }
 /// #  fn metrics(&self) -> &ExecutionPlanMetricsSet { unimplemented!() }
-/// #  fn statistics(&self) -> datafusion_common::Result<Statistics> { unimplemented!() }
+/// #  fn statistics(&self) -> datafusion_common::Result<Statistics> { Ok(self.projected_statistics.clone().expect("projected_statistics should be set")) }
 /// #  fn file_type(&self) -> &str { "parquet" }
 /// #  }
 /// # impl ParquetSource {
-/// #  fn new() -> Self { Self{} }
+/// #  fn new() -> Self { Self {projected_statistics: None} }
 /// # }
 /// // create FileScan config for reading parquet files from file://
 /// let object_store_url = ObjectStoreUrl::local_filesystem();
@@ -244,7 +244,7 @@ impl DataSource for FileScanConfig {
     }
 
     fn statistics(&self) -> Result<Statistics> {
-        self.file_source.statistics()
+        Ok(self.projected_stats())
     }
 
     fn with_fetch(&self, limit: Option<usize>) -> Option<Arc<dyn DataSource>> {
@@ -324,13 +324,7 @@ impl FileScanConfig {
 
     /// Set the file source
     pub fn with_source(mut self, file_source: Arc<dyn FileSource>) -> Self {
-        let (
-            _projected_schema,
-            _constraints,
-            projected_statistics,
-            _projected_output_ordering,
-        ) = self.project();
-        self.file_source = file_source.with_statistics(projected_statistics);
+        self.file_source = file_source.with_statistics(self.statistics.clone());
         self
     }
 
@@ -342,10 +336,75 @@ impl FileScanConfig {
 
     /// Set the statistics of the files
     pub fn with_statistics(mut self, statistics: Statistics) -> Self {
-        self.statistics = statistics;
+        self.statistics = statistics.clone();
+        self.file_source = self.file_source.with_statistics(statistics);
         self
     }
 
+    fn projection_indices(&self) -> Vec<usize> {
+        match &self.projection {
+            Some(proj) => proj.clone(),
+            None => (0..self.file_schema.fields().len()
+                + self.table_partition_cols.len())
+                .collect(),
+        }
+    }
+
+    fn projected_stats(&self) -> Statistics {
+        let statistics = self
+            .file_source
+            .statistics()
+            .unwrap_or(self.statistics.clone());
+
+        let table_cols_stats = self
+            .projection_indices()
+            .into_iter()
+            .map(|idx| {
+                if idx < self.file_schema.fields().len() {
+                    statistics.column_statistics[idx].clone()
+                } else {
+                    // TODO provide accurate stat for partition column (#1186)
+                    ColumnStatistics::new_unknown()
+                }
+            })
+            .collect();
+
+        Statistics {
+            num_rows: statistics.num_rows,
+            // TODO correct byte size: https://github.com/apache/datafusion/issues/14936
+            total_byte_size: statistics.total_byte_size,
+            column_statistics: table_cols_stats,
+        }
+    }
+
+    fn projected_schema(&self) -> Arc<Schema> {
+        let table_fields: Vec<_> = self
+            .projection_indices()
+            .into_iter()
+            .map(|idx| {
+                if idx < self.file_schema.fields().len() {
+                    self.file_schema.field(idx).clone()
+                } else {
+                    let partition_idx = idx - self.file_schema.fields().len();
+                    self.table_partition_cols[partition_idx].clone()
+                }
+            })
+            .collect();
+
+        Arc::new(Schema::new_with_metadata(
+            table_fields,
+            self.file_schema.metadata().clone(),
+        ))
+    }
+
+    fn projected_constraints(&self) -> Constraints {
+        let indexes = self.projection_indices();
+
+        self.constraints
+            .project(&indexes)
+            .unwrap_or_else(Constraints::empty)
+    }
+
     /// Set the projection of the files
     pub fn with_projection(mut self, projection: Option<Vec<usize>>) -> Self {
         self.projection = projection;
@@ -433,54 +492,13 @@ impl FileScanConfig {
             );
         }
 
-        let proj_indices = if let Some(proj) = &self.projection {
-            proj
-        } else {
-            let len = self.file_schema.fields().len() + self.table_partition_cols.len();
-            &(0..len).collect::<Vec<_>>()
-        };
-
-        let mut table_fields = vec![];
-        let mut table_cols_stats = vec![];
-        for idx in proj_indices {
-            if *idx < self.file_schema.fields().len() {
-                let field = self.file_schema.field(*idx);
-                table_fields.push(field.clone());
-                table_cols_stats.push(self.statistics.column_statistics[*idx].clone())
-            } else {
-                let partition_idx = idx - self.file_schema.fields().len();
-                table_fields.push(self.table_partition_cols[partition_idx].to_owned());
-                // TODO provide accurate stat for partition column (#1186)
-                table_cols_stats.push(ColumnStatistics::new_unknown())
-            }
-        }
-
-        let table_stats = Statistics {
-            num_rows: self.statistics.num_rows,
-            // TODO correct byte size?
-            total_byte_size: Precision::Absent,
-            column_statistics: table_cols_stats,
-        };
-
-        let projected_schema = Arc::new(Schema::new_with_metadata(
-            table_fields,
-            self.file_schema.metadata().clone(),
-        ));
+        let schema = self.projected_schema();
+        let constraints = self.projected_constraints();
+        let stats = self.projected_stats();
 
-        let projected_constraints = self
-            .constraints
-            .project(proj_indices)
-            .unwrap_or_else(Constraints::empty);
+        let output_ordering = get_projected_output_ordering(self, &schema);
 
-        let projected_output_ordering =
-            get_projected_output_ordering(self, &projected_schema);
-
-        (
-            projected_schema,
-            projected_constraints,
-            table_stats,
-            projected_output_ordering,
-        )
+        (schema, constraints, stats, output_ordering)
     }
 
     #[cfg_attr(not(feature = "avro"), allow(unused))] // Only used by avro
@@ -1048,6 +1066,7 @@ mod tests {
         compute::SortOptions,
     };
 
+    use datafusion_common::stats::Precision;
     use datafusion_common::{assert_batches_eq, DFSchema};
     use datafusion_expr::{execution_props::ExecutionProps, SortExpr};
     use datafusion_physical_expr::create_physical_expr;
@@ -1203,6 +1222,12 @@ mod tests {
             ),
         ];
         // create a projected schema
+        let statistics = Statistics {
+            num_rows: Precision::Inexact(3),
+            total_byte_size: Precision::Absent,
+            column_statistics: Statistics::unknown_column(&file_batch.schema()),
+        };
+
         let conf = config_for_projection(
             file_batch.schema(),
             // keep all cols from file and 2 from partitioning
@@ -1213,9 +1238,23 @@ mod tests {
                 file_batch.schema().fields().len(),
                 file_batch.schema().fields().len() + 2,
             ]),
-            Statistics::new_unknown(&file_batch.schema()),
+            statistics.clone(),
             to_partition_cols(partition_cols.clone()),
         );
+
+        let source_statistics = conf.file_source.statistics().unwrap();
+        let conf_stats = conf.statistics().unwrap();
+
+        // projection should be reflected in the file source statistics
+        assert_eq!(conf_stats.num_rows, Precision::Inexact(3));
+
+        // 3 original statistics + 2 partition statistics
+        assert_eq!(conf_stats.column_statistics.len(), 5);
+
+        // file statics should not be modified
+        assert_eq!(source_statistics, statistics);
+        assert_eq!(source_statistics.column_statistics.len(), 3);
+
         let (proj_schema, ..) = conf.project();
         // created a projector for that projected schema
         let mut proj = PartitionColumnProjector::new(