PERF-modin-project#6524: Add a 'column' shape hint for the results of…

… 'qc.to_datetime()'

Signed-off-by: Dmitry Chigarev <dmitry.chigarev@intel.com>

modin/core/dataframe/algebra/reduce.py

@@ -20,7 +20,7 @@ class Reduce(Operator):
     """Builder class for Reduce operator."""
 
     @classmethod
-    def register(cls, reduce_function, axis=None):
+    def register(cls, reduce_function, axis=None, shape_hint=None):
         """
         Build Reduce operator that will be performed across rows/columns.
 
@@ -32,6 +32,8 @@ def register(cls, reduce_function, axis=None):
             Source function.
         axis : int, optional
             Axis to apply function along.
+        shape_hint : {"row", "column", None}, default: None
+            Shape hint for the results known to be a column or a row, otherwise None.
 
         Returns
         -------
@@ -46,7 +48,8 @@ def caller(query_compiler, *args, **kwargs):
                 query_compiler._modin_frame.reduce(
                     cls.validate_axis(_axis),
                     lambda x: reduce_function(x, *args, **kwargs),
-                )
+                ),
+                shape_hint=shape_hint,
             )
 
         return caller

modin/core/storage_formats/pandas/query_compiler.py

@@ -1029,10 +1029,13 @@ def to_datetime(self, *args, **kwargs):
                 # to_datetime has inplace side effects, see GH#3063
                 lambda df, *args, **kwargs: pandas.to_datetime(
                     df.squeeze(axis=1), *args, **kwargs
-                ).to_frame()
+                ).to_frame(),
+                shape_hint="column",
             )(self, *args, **kwargs)
         else:
-            return Reduce.register(pandas.to_datetime, axis=1)(self, *args, **kwargs)
+            return Reduce.register(pandas.to_datetime, axis=1, shape_hint="column")(
+                self, *args, **kwargs
+            )
 
     # END Reduce operations