Fix join on arrays of unhashable types

Update can_hash to match currently supported hashes.

Author: findepi

datafusion/expr/src/utils.rs

@@ -29,7 +29,7 @@ use crate::{
 };
 use datafusion_expr_common::signature::{Signature, TypeSignature};
 
-use arrow::datatypes::{DataType, Field, Schema, TimeUnit};
+use arrow::datatypes::{DataType, Field, Schema};
 use datafusion_common::tree_node::{
     Transformed, TransformedResult, TreeNode, TreeNodeRecursion,
 };
@@ -958,7 +958,7 @@ pub(crate) fn find_column_indexes_referenced_by_expr(
 
 /// Can this data type be used in hash join equal conditions??
 /// Data types here come from function 'equal_rows', if more data types are supported
-/// in equal_rows(hash join), add those data types here to generate join logical plan.
+/// in create_hashes, add those data types here to generate join logical plan.
 pub fn can_hash(data_type: &DataType) -> bool {
     match data_type {
         DataType::Null => true,
@@ -971,31 +971,38 @@ pub fn can_hash(data_type: &DataType) -> bool {
         DataType::UInt16 => true,
         DataType::UInt32 => true,
         DataType::UInt64 => true,
+        DataType::Float16 => true,
         DataType::Float32 => true,
         DataType::Float64 => true,
-        DataType::Timestamp(time_unit, _) => match time_unit {
-            TimeUnit::Second => true,
-            TimeUnit::Millisecond => true,
-            TimeUnit::Microsecond => true,
-            TimeUnit::Nanosecond => true,
-        },
+        DataType::Decimal128(_, _) => true,
+        DataType::Decimal256(_, _) => true,
+        DataType::Timestamp(_, _) => true,
         DataType::Utf8 => true,
         DataType::LargeUtf8 => true,
         DataType::Utf8View => true,
-        DataType::Decimal128(_, _) => true,
+        DataType::Binary => true,
+        DataType::LargeBinary => true,
+        DataType::BinaryView => true,
         DataType::Date32 => true,
         DataType::Date64 => true,
+        DataType::Time32(_) => true,
+        DataType::Time64(_) => true,
+        DataType::Duration(_) => true,
+        DataType::Interval(_) => true,
         DataType::FixedSizeBinary(_) => true,
-        DataType::Dictionary(key_type, value_type)
-            if *value_type.as_ref() == DataType::Utf8 =>
-        {
-            DataType::is_dictionary_key_type(key_type)
+        DataType::Dictionary(key_type, value_type) => {
+            DataType::is_dictionary_key_type(key_type) && can_hash(value_type)
         }
-        DataType::List(_) => true,
-        DataType::LargeList(_) => true,
-        DataType::FixedSizeList(_, _) => true,
+        DataType::List(value_type) => can_hash(value_type.data_type()),
+        DataType::LargeList(value_type) => can_hash(value_type.data_type()),
+        DataType::FixedSizeList(value_type, _) => can_hash(value_type.data_type()),
+        DataType::Map(map_struct, true | false) => can_hash(map_struct.data_type()),
         DataType::Struct(fields) => fields.iter().all(|f| can_hash(f.data_type())),
-        _ => false,
+
+        DataType::ListView(_)
+        | DataType::LargeListView(_)
+        | DataType::Union(_, _)
+        | DataType::RunEndEncoded(_, _) => false,
     }
 }
 
@@ -1403,6 +1410,7 @@ mod tests {
         test::function_stub::max_udaf, test::function_stub::min_udaf,
         test::function_stub::sum_udaf, Cast, ExprFunctionExt, WindowFunctionDefinition,
     };
+    use arrow::datatypes::{UnionFields, UnionMode};
 
     #[test]
     fn test_group_window_expr_by_sort_keys_empty_case() -> Result<()> {
@@ -1805,4 +1813,21 @@ mod tests {
         assert!(accum.contains(&Column::from_name("a")));
         Ok(())
     }
+
+    #[test]
+    fn test_can_hash() {
+        let union_fields: UnionFields = [
+            (0, Arc::new(Field::new("A", DataType::Int32, true))),
+            (1, Arc::new(Field::new("B", DataType::Float64, true))),
+        ]
+        .into_iter()
+        .collect();
+
+        let union_type = DataType::Union(union_fields, UnionMode::Sparse);
+        assert!(!can_hash(&union_type));
+
+        let list_union_type =
+            DataType::List(Arc::new(Field::new("my_union", union_type, true)));
+        assert!(!can_hash(&list_union_type));
+    }
 }