PERF: skip non-consolidatable blocks when checking consolidation (#32826)

Author: jorisvandenbossche

pandas/core/arrays/sparse/array.py

@@ -268,7 +268,6 @@ class SparseArray(PandasObject, ExtensionArray, ExtensionOpsMixin):
     Indices: array([2, 3], dtype=int32)
     """
 
-    _pandas_ftype = "sparse"
     _subtyp = "sparse_array"  # register ABCSparseArray
     _deprecations = PandasObject._deprecations | frozenset(["get_values"])
     _sparse_index: SparseIndex

pandas/core/internals/blocks.py

@@ -110,7 +110,6 @@ class Block(PandasObject):
     _can_consolidate = True
     _verify_integrity = True
     _validate_ndim = True
-    _ftype = "dense"
     _concatenator = staticmethod(np.concatenate)
 
     def __init__(self, values, placement, ndim=None):
@@ -322,14 +321,6 @@ def shape(self):
     def dtype(self):
         return self.values.dtype
 
-    @property
-    def ftype(self) -> str:
-        if getattr(self.values, "_pandas_ftype", False):
-            dtype = self.dtype.subtype
-        else:
-            dtype = self.dtype
-        return f"{dtype}:{self._ftype}"
-
     def merge(self, other):
         return _merge_blocks([self, other])
 
@@ -1956,10 +1947,6 @@ def where(
 
         return [self.make_block_same_class(result, placement=self.mgr_locs)]
 
-    @property
-    def _ftype(self):
-        return getattr(self.values, "_pandas_ftype", Block._ftype)
-
     def _unstack(self, unstacker_func, new_columns, n_rows, fill_value):
         # ExtensionArray-safe unstack.
         # We override ObjectBlock._unstack, which unstacks directly on the

pandas/core/internals/managers.py

@@ -676,8 +676,8 @@ def is_consolidated(self) -> bool:
         return self._is_consolidated
 
     def _consolidate_check(self) -> None:
-        ftypes = [blk.ftype for blk in self.blocks]
-        self._is_consolidated = len(ftypes) == len(set(ftypes))
+        dtypes = [blk.dtype for blk in self.blocks if blk._can_consolidate]
+        self._is_consolidated = len(dtypes) == len(set(dtypes))
         self._known_consolidated = True
 
     @property