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Mike Bayer
053b84c56d
Changed the bulk INSERT strategy used for SQL Server "executemany" with pyodbc when ``fast_executemany`` is set to ``True`` by using ``fast_executemany`` / ``cursor.executemany()`` for bulk INSERT that does not include RETURNING, restoring the same behavior as was used in SQLAlchemy 1.4 when this parameter is set. For INSERT statements that use RETURNING, the "insertmanyvalues" strategy continues to be used as it is the only current strategy that supports RETURNING with bulk INSERT. Previously, SQLAlchemy 2.0 would use "insertmanyvalues" for all INSERT statements when ``use_insertmanyvalues`` was left at its default of ``False``, ignoring if ``fast_executemany`` was set. New performance details from end users have shown that ``fast_executemany`` is still much faster for very large datasets as it uses ODBC commands that can receive all rows in a single round trip, allowing for much larger datasizes than the batches that can be sent by the current "insertmanyvalues" strategy. Fixes: #9586 Change-Id: I85955a10ba77c26cdc0c22e362a827d7aaef2852