paleolimbot commented on code in PR #1116:
URL: https://github.com/apache/sedona-db/pull/1116#discussion_r3738717845
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rust/sedona-geoparquet/src/format.rs:
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@@ -391,7 +391,34 @@ impl FileFormat for GeoParquetFormat {
)
.unwrap();
source.options = self.options.clone();
- Arc::new(source)
+
+ // DataFusion 52 has an issue where field metadata (like
ARROW:extension:name)
+ // is stripped when evaluating embedded projections in ParquetOpener.
This is
+ // because the batch schema comes from the parquet reader (which
doesn't have
+ // extension metadata), and Column::return_field() looks up fields
from that schema.
+ // This isn't a bug in DataFusion because we're the ones that
advertised the table
+ // schema as having metadata'd expressions in the first place.
+ //
+ // We fix this by wrapping Column expressions with
MetadataPreservingColumn,
+ // which stores the correct field from the file schema and returns it
from
+ // return_field() regardless of the input schema.
+ let initial_projection =
source.projection().cloned().unwrap_or_else(|| {
+ let indices: Vec<usize> =
+
(0..source.table_schema().table_schema().fields().len()).collect();
+ ProjectionExprs::from_indices(&indices,
source.table_schema().table_schema())
+ });
+ let projection_with_types = wrap_columns_with_metadata_preserving(
+ initial_projection,
+ source.table_schema().table_schema(),
+ )
+ .map(|projection_with_types|
source.try_pushdown_projection(&projection_with_types));
+
+ // These are both failable but we can't fail here, so fall back to the
original
+ // source.
+ match projection_with_types {
+ Ok(Ok(Some(modified))) => modified,
+ _ => Arc::new(source),
Review Comment:
That's a great point...it's not expected to fail but I added a deferred
error mechanism to make sure we know if it does
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