PERF: DataFrame[object].fillna (pandas-dev#43316)

Author: jbrockmendel

pandas/core/internals/blocks.py

@@ -1084,6 +1084,23 @@ def interpolate(
             # If there are no NAs, then interpolate is a no-op
             return [self] if inplace else [self.copy()]
 
+        if self.is_object and self.ndim == 2 and self.shape[0] != 1 and axis == 0:
+            # split improves performance in ndarray.copy()
+            return self.split_and_operate(
+                type(self).interpolate,
+                method,
+                axis,
+                index,
+                inplace,
+                limit,
+                limit_direction,
+                limit_area,
+                fill_value,
+                coerce,
+                downcast,
+                **kwargs,
+            )
+
         try:
             m = missing.clean_fill_method(method)
         except ValueError: