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| author | Mike Bayer <mike_mp@zzzcomputing.com> | 2023-04-05 19:27:10 -0400 |
|---|---|---|
| committer | Mike Bayer <mike_mp@zzzcomputing.com> | 2023-04-05 19:27:10 -0400 |
| commit | 582e4184ad2af8300fcf7742afb12db09c0a03c8 (patch) | |
| tree | 9d450f5367dc91da03f26f8c02bbfb39b6522a18 /doc | |
| parent | 7fb7365622ee751b264bbbd4e7394ef8e81d45c5 (diff) | |
| download | sqlalchemy-582e4184ad2af8300fcf7742afb12db09c0a03c8.tar.gz | |
revise changelog for #9586
this would be misleading due to #9603 disabling insertmanyvalues
across the board.
Change-Id: I0e746e13f8ad054207790644cb43eba101dde30c
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/build/changelog/unreleased_20/9586.rst | 17 |
1 files changed, 8 insertions, 9 deletions
diff --git a/doc/build/changelog/unreleased_20/9586.rst b/doc/build/changelog/unreleased_20/9586.rst index d8abe1a5f..4dce60d63 100644 --- a/doc/build/changelog/unreleased_20/9586.rst +++ b/doc/build/changelog/unreleased_20/9586.rst @@ -6,16 +6,15 @@ 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. + SQLAlchemy 1.4 when this parameter is 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. + datasizes than the batches that can be sent by "insertmanyvalues" + as was implemented for SQL Server. + + While this change was made such that "insertmanyvalues" continued to be + used for INSERT that includes RETURNING, as well as if ``fast_executemany`` + were not set, due to :ticket:`9603`, the "insertmanyvalues" strategy has + been disabled for SQL Server across the board in any case. |
