PERF: route setinputsizes through the native C++ execute pipeline

[Gaurav Sharma (bewithgaurav)]

Work Item / Issue Reference

GitHub Issue: #500

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Summary

move setinputsizes overrides into the native detect, bind, and execute path and remove DDBCSQLExecuteLegacy.

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Performance Results

macOS arm64, Python 3.13, SQL Server 2022, release build

Path	Median	Improvement
main legacy path	2.205s
this PR native path	1.686s	24% faster

the issue #500 workload runs 100 executions with 2,000 declared parameters each (1,000 INT/VARCHAR rows), calling setinputsizes() before every execute. results are the median of three runs and were confirmed with the base/PR execution order reversed.

Cross-platform CI

Platform	main	This PR	Raw improvement
Windows SQL2022	4.0770s	2.8424s	30.3% faster
Windows SQL2025	3.8320s	3.1110s	18.8% faster
macOS SQL2022	18.0371s	9.0534s	49.8% faster
macOS SQL2025	9.6811s	7.1356s	26.3% faster
Linux SQL2022	2.7965s	2.3523s	15.9% faster

main results are from build 171915. PR results are from build 172065, except macOS SQL2022, which is from the last completed run in build 171939; the rerun reached the 20-minute benchmark timeout before that scenario completed.

these are raw medians. the existing pyodbc-normalized score is not used here because the Windows pyodbc main baseline did not reproduce across hosted runners.

[Copilot]

Pull request overview

Moves setinputsizes handling into the native execute pipeline to reduce parameter-binding overhead.

Changes:

• Adds native input-size override handling, normalization, and numeric clamping.
• Removes DDBCSQLExecuteLegacy and routes execution through native bindings.
• Expands execute-path parity tests.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
mssql_python/cursor.py	Routes parameterized execution through the native path.
mssql_python/pybind/ddbc_bindings.cpp	Removes legacy execution and accepts input sizes natively.
mssql_python/pybind/param_detect.hpp	Applies native type overrides and value normalization.
mssql_python/pybind/py_type_cache.hpp	Simplifies access to initialized type caches.
tests/test_010_pybind_functions.py	Updates expected native exports.
tests/test_023_execute_path_parity.py	Tests native override behavior and edge cases.

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[github-actions]

📊 Code Coverage Report

🔥 Diff Coverage 90%

🎯 Overall Coverage 83%

📈 Total Lines Covered: 7776 out of 9321 📁 Project: mssql-python

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Diff Coverage

Diff: main...HEAD, staged and unstaged changes

• mssql_python/cursor.py (100%)
• mssql_python/pybind/ddbc_bindings.cpp (0.0%): Missing lines 1902
• mssql_python/pybind/param_detect.hpp (93.0%): Missing lines 188-189,200-201,214-215
• mssql_python/pybind/py_type_cache.hpp (70.0%): Missing lines 66-68

Summary

• Total: 104 lines
• Missing: 10 lines
• Coverage: 90%

mssql_python/pybind/ddbc_bindings.cpp

Lines 1898-1906

  1898 
  1899     // Run DetectParamTypes BEFORE SQLPrepare so that type-detection errors
  1900     // (unsupported type, NaN Decimal, precision overflow) don't leave the
  1901     // cursor in a half-prepared state.
! 1902     std::vector<ParamInfo> paramInfos = DetectParamTypes(params.ptr(), input_sizes.ptr());
  1903 
  1904     RETCODE rc;
  1905     bool already_prepared = is_stmt_prepared[0].cast<bool>();

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mssql_python/pybind/param_detect.hpp

Lines 184-193

  184 inline bool PyLongGreaterThan(PyObject* value, long long threshold) {
  185     int overflow = 0;
  186     long long result = PyLong_AsLongLongAndOverflow(value, &overflow);
  187     if (result == -1 && PyErr_Occurred()) {
! 188         throw py::error_already_set();
! 189     }
  190     return overflow > 0 || (overflow == 0 && result > threshold);
  191 }
  192 
  193 inline PyObject* FormatDecimalParam(PyObject* params, Py_ssize_t index, PyObject* value) {

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Lines 196-205

  196     if (!PyUnicode_Check(formatted.ptr())) {
  197         throw py::type_error("Decimal.__format__() must return a str");
  198     }
  199     if (PyList_SetItem(params, index, formatted.release().ptr()) != 0) {
! 200         throw py::error_already_set();
! 201     }
  202     return PyList_GET_ITEM(params, index);
  203 }
  204 
  205 inline void NormalizeTimeParam(PyObject* params, Py_ssize_t index, SQLULEN& columnSize) {

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Lines 210-219

  210         throw py::type_error("datetime.time.isoformat() must return a str");
  211     }
  212     columnSize = std::max<SQLULEN>(columnSize, PyUnicode_GET_LENGTH(formatted.ptr()));
  213     if (PyList_SetItem(params, index, formatted.release().ptr()) != 0) {
! 214         throw py::error_already_set();
! 215     }
  216 }
  217 
  218 inline void ApplyInputSizeOverride(PyObject* params, PyObject* inputSize, Py_ssize_t index,
  219                                    ParamInfo& info) {

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mssql_python/pybind/py_type_cache.hpp

Lines 62-72

  62     uuid_class     = uuid_cls.release().ptr();
  63     cache_initialized = true;
  64 }
  65 
! 66 inline PyObject* get_datetime_class() { return datetime_class; }
! 67 inline PyObject* get_date_class()     { return date_class; }
! 68 inline PyObject* get_time_class()     { return time_class; }
  69 inline PyObject* get_decimal_class()  { return decimal_class; }
  70 inline PyObject* get_uuid_class()     { return uuid_class; }
  71 
  72 inline py::object get_datetime_class_obj() { return borrow(datetime_class); }

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📋 Files Needing Attention

📉 Files with overall lowest coverage (click to expand)

mssql_python.pybind.logger_bridge.cpp: 58.9%
mssql_python.pybind.ddbc_bindings.h: 61.5%
mssql_python.pybind.logger_bridge.hpp: 70.8%
mssql_python.pybind.ddbc_bindings.cpp: 77.5%
mssql_python.__init__.py: 77.6%
mssql_python.row.py: 77.6%
mssql_python.pybind.connection.connection_pool.cpp: 81.6%
mssql_python.pybind.connection.connection.cpp: 84.4%
mssql_python.logging.py: 85.5%
mssql_python.connection.py: 85.9%

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[Copilot]

🔵 Needs a closer look

Native ODBC binding changes affect cross-platform type conversion, memory ownership, and DAE streaming and require final human validation.

Review details

• Files reviewed: 6/6 changed files
• Comments generated: 0 new
• Review effort level: Balanced

[gargsaumya]

LGTM