FIX-modin-project#6879 : Convert the right DF to single partition bef…

…ore broadcasting

Signed-off-by: arunjose696 <arunjose696@gmail.com>

modin/core/dataframe/pandas/dataframe/dataframe.py

@@ -2656,6 +2656,37 @@ def explode(self, axis: Union[int, Axis], func: Callable) -> "PandasDataframe":
             partitions, new_index, new_columns, row_lengths, column_widths
         )
 
+    def force_materialization(self) -> "PandasDataframe":
+        """
+        Materialize axis partitions into a single partition.
+
+        Applies the identity function first across rows, and thereafter across columns
+        to get a df single  partition.
+
+
+        Returns
+        -------
+        PandasDataframe
+            An PandasDataframe containing only a single partition.
+        """
+        single_col_aggregated_df = self.apply_full_axis(
+            axis=0,
+            func=lambda x: x,
+            keep_partitioning=False,
+            num_splits=1,
+            sync_labels=True,
+            pass_axis_lengths_to_partitions=False,
+        )
+        single_partition_df = single_col_aggregated_df.apply_full_axis(
+            axis=1,
+            func=lambda x: x,
+            keep_partitioning=False,
+            num_splits=1,
+            sync_labels=True,
+            pass_axis_lengths_to_partitions=False,
+        )
+        return single_partition_df
+
     @lazy_metadata_decorator(apply_axis="both")
     def apply_full_axis(
         self,

modin/core/storage_formats/pandas/query_compiler.py

@@ -520,7 +520,7 @@ def merge(self, right, **kwargs):
         left_index = kwargs.get("left_index", False)
         right_index = kwargs.get("right_index", False)
         sort = kwargs.get("sort", False)
-
+        right = self.__constructor__(right._modin_frame.force_materialization())
         if how in ["left", "inner"] and left_index is False and right_index is False:
             kwargs["sort"] = False