DOC: Perf notes (#44101)

Author: jbrockmendel

doc/source/whatsnew/v1.4.0.rst

@@ -403,21 +403,46 @@ Performance improvements
 - Performance improvement in :meth:`.GroupBy.sample`, especially when ``weights`` argument provided (:issue:`34483`)
 - Performance improvement when converting non-string arrays to string arrays (:issue:`34483`)
 - Performance improvement in :meth:`.GroupBy.transform` for user-defined functions (:issue:`41598`)
-- Performance improvement in constructing :class:`DataFrame` objects (:issue:`42631`)
+- Performance improvement in constructing :class:`DataFrame` objects (:issue:`42631`, :issue:`43142`, :issue:`43147`, :issue:`43307`, :issue:`43144`)
 - Performance improvement in :meth:`GroupBy.shift` when ``fill_value`` argument is provided (:issue:`26615`)
 - Performance improvement in :meth:`DataFrame.corr` for ``method=pearson`` on data without missing values (:issue:`40956`)
-- Performance improvement in some :meth:`GroupBy.apply` operations (:issue:`42992`)
-- Performance improvement in :func:`read_stata` (:issue:`43059`)
+- Performance improvement in some :meth:`GroupBy.apply` operations (:issue:`42992`, :issue:`43578`)
+- Performance improvement in :func:`read_stata` (:issue:`43059`, :issue:`43227`)
+- Performance improvement in :func:`read_sas` (:issue:`43333`)
 - Performance improvement in :meth:`to_datetime` with ``uint`` dtypes (:issue:`42606`)
 - Performance improvement in :meth:`to_datetime` with ``infer_datetime_format`` set to ``True`` (:issue:`43901`)
 - Performance improvement in :meth:`Series.sparse.to_coo` (:issue:`42880`)
+- Performance improvement in indexing with a :class:`UInt64Index` (:issue:`43862`)
+- Performance improvement in indexing with a :class:`Float64Index` (:issue:`43705`)
+- Performance improvement in indexing with a non-unique Index (:issue:`43792`)
+- Performance improvement in indexing with a listlike indexer on a :class:`MultiIndex` (:issue:`43370`)
 - Performance improvement in indexing with a :class:`MultiIndex` indexer on another :class:`MultiIndex` (:issue:43370`)
-- Performance improvement in :meth:`GroupBy.quantile` (:issue:`43469`)
+- Performance improvement in :meth:`GroupBy.quantile` (:issue:`43469`, :issue:`43725`)
+- Performance improvement in :meth:`GroupBy.count` (:issue:`43730`, :issue:`43694`)
+- Performance improvement in :meth:`GroupBy.any` and :meth:`GroupBy.all` (:issue:`43675`, :issue:`42841`)
+- Performance improvement in :meth:`GroupBy.std` (:issue:`43115`, :issue:`43576`)
+- Performance improvement in :meth:`GroupBy.cumsum` (:issue:`43309`)
 - :meth:`SparseArray.min` and :meth:`SparseArray.max` no longer require converting to a dense array (:issue:`43526`)
 - Indexing into a :class:`SparseArray` with a ``slice`` with ``step=1`` no longer requires converting to a dense array (:issue:`43777`)
 - Performance improvement in :meth:`SparseArray.take` with ``allow_fill=False`` (:issue:`43654`)
 - Performance improvement in :meth:`.Rolling.mean` and :meth:`.Expanding.mean` with ``engine="numba"`` (:issue:`43612`)
 - Improved performance of :meth:`pandas.read_csv` with ``memory_map=True`` when file encoding is UTF-8 (:issue:`43787`)
+- Performance improvement in :meth:`RangeIndex.insert` (:issue:`43988`)
+- Performance improvement in :meth:`Index.insert` (:issue:`43953`)
+- Performance improvement in :meth:`DatetimeIndex.tolist` (:issue:`43823`)
+- Performance improvement in :meth:`DatetimeIndex.union` (:issue:`42353`)
+- Performance improvement in :meth:`Series.nsmallest` (:issue:`43696`)
+- Performance improvement in :meth:`DataFrame.insert` (:issue:`42998`)
+- Performance improvement in :meth:`DataFrame.dropna` (:issue:`43683`)
+- Performance improvement in :meth:`DataFrame.fillna` (:issue:`43316`)
+- Performance improvement in :meth:`DataFrame.values` (:issue:`43160`)
+- Performance improvement in :meth:`DataFrame.select_dtypes` (:issue:`42611`)
+- Performance improvement in :class:`DataFrame` reductions (:issue:`43185`, :issue:`43243`, :issue:`43311`, :issue:`43609`)
+- Performance improvement in :meth:`Series.unstack` and :meth:`DataFrame.unstack` (:issue:`43335`, :issue:`43352`, :issue:`42704`, :issue:`43025`)
+- Performance improvement in :meth:`Series.to_frame` (:issue:`43558`)
+- Performance improvement in :meth:`Series.mad` (:issue:`43010`)
+- Performance improvement in :func:`merge` (:issue:`43332`)
+- Performance improvement in :func:`concat` (:issue:`43354`)
 -
 
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