FEAT-#1936: avoid empty frame checks for lazy backend (#1937)

Signed-off-by: ienkovich <ilya.enkovich@intel.com>

modin/backends/base/query_compiler.py

@@ -45,6 +45,8 @@ def default_to_pandas(self, pandas_op, *args, **kwargs):
     # some of these abstract methods, but for the sake of generality they are
     # treated differently.
 
+    lazy_execution = False
+
     # Metadata modification abstract methods
     @abc.abstractmethod
     def add_prefix(self, prefix, axis=1):

modin/pandas/base.py

@@ -3438,7 +3438,7 @@ def __ge__(self, right):
         return self.ge(right)
 
     def __getitem__(self, key):
-        if len(self) == 0:
+        if not self._query_compiler.lazy_execution and len(self) == 0:
             return self._default_to_pandas("__getitem__", key)
         # see if we can slice the rows
         # This lets us reuse code in Pandas to error check
@@ -3574,7 +3574,7 @@ def __getattribute__(self, item):
             "_create_or_update_from_compiler",
             "_update_inplace",
         ]
-        if item not in default_behaviors:
+        if item not in default_behaviors and not self._query_compiler.lazy_execution:
             method = object.__getattribute__(self, item)
             is_callable = callable(method)
             # We default to pandas on empty DataFrames. This avoids a large amount of

modin/pandas/concat.py

@@ -106,7 +106,8 @@ def concat(
     list_of_objs = [
         obj._query_compiler
         for obj in list_of_objs
-        if len(obj.index) or len(obj.columns)
+        if (not obj._query_compiler.lazy_execution and len(obj.index))
+        or len(obj.columns)
     ]
     if keys is not None:
         if all_series:

modin/pandas/dataframe.py

@@ -1134,7 +1134,7 @@ def insert(self, loc, column, value, allow_duplicates=False):
             # TODO: Remove broadcast of Series
             value = value._to_pandas()
 
-        if len(self.index) == 0:
+        if not self._query_compiler.lazy_execution and len(self.index) == 0:
             try:
                 value = pandas.Series(value)
             except (TypeError, ValueError, IndexError):
@@ -2577,7 +2577,7 @@ def setitem_without_string_columns(df):
             if not isinstance(value, Series):
                 value = list(value)
 
-        if len(self.index) == 0:
+        if not self._query_compiler.lazy_execution and len(self.index) == 0:
             new_self = DataFrame({key: value}, columns=self.columns)
             self._update_inplace(new_self._query_compiler)
         else: