Veeupup commented on code in PR #8413:
URL: https://github.com/apache/arrow-datafusion/pull/8413#discussion_r1415338241
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datafusion-cli/src/functions.rs:
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@@ -196,3 +209,110 @@ pub fn display_all_functions() -> Result<()> {
println!("{}", pretty_format_batches(&[batch]).unwrap());
Ok(())
}
+
+/// PARQUET_META table function
+struct ParquetMetadataTable {
+ schema: SchemaRef,
+ batch: RecordBatch,
+}
+
+#[async_trait]
+impl TableProvider for ParquetMetadataTable {
+ fn as_any(&self) -> &dyn std::any::Any {
+ self
+ }
+
+ fn schema(&self) -> arrow::datatypes::SchemaRef {
+ self.schema.clone()
+ }
+
+ fn table_type(&self) -> datafusion::logical_expr::TableType {
+ datafusion::logical_expr::TableType::Base
+ }
+
+ async fn scan(
+ &self,
+ _state: &SessionState,
+ projection: Option<&Vec<usize>>,
+ _filters: &[Expr],
+ _limit: Option<usize>,
+ ) -> Result<Arc<dyn ExecutionPlan>> {
+ Ok(Arc::new(MemoryExec::try_new(
+ &[vec![self.batch.clone()]],
+ TableProvider::schema(self),
+ projection.cloned(),
+ )?))
+ }
+}
+
+pub struct ParquetMetadataFunc {}
+
+impl TableFunctionImpl for ParquetMetadataFunc {
+ fn call(&self, exprs: &[Expr]) -> Result<Arc<dyn TableProvider>> {
+ let Some(Expr::Column(Column { name, .. })) = exprs.get(0) else {
+ return plan_err!("read_csv requires at least one string argument");
+ };
+
+ let file = File::open(name)?;
+ let reader = SerializedFileReader::new(file)?;
+ let metadata = reader.metadata();
+
+ let schema = Arc::new(Schema::new(vec![
+ Field::new("version", DataType::Int32, false),
+ Field::new("num_rows", DataType::Int64, false),
+ Field::new("created_by", DataType::Utf8, false),
+ Field::new("columns_order", DataType::Utf8, false),
+ Field::new("num_row_groups", DataType::Int64, false),
+ Field::new("row_groups", DataType::Utf8, false),
Review Comment:
Yeah, agree with you! a list of structs would be more precise! I implement
the first version schema using `List(Struct)`.
But if the list contains lots of row_groups (100+ or more), then all 100+
rows groups will be displayed in one cell.
Then the display may look not so user-friendly?
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