CHORE: TEST PR Performance Report control path

[Gaurav Sharma (bewithgaurav)]

Work Item / Issue Reference

ADO Work Item: AB#44819

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Summary

Disposable control canary for the merged PR Performance Report. This branch changes only an invisible README marker, so the report should complete across five environments without detecting a performance regression. This PR will not be merged.

[github-actions]

PR Performance Report

This PR has 4 consistent improvement signals across 2 database tasks and 2 environments.

Environment	Affected task	Before	After	Change
Unix / SQL Server 2022	Insertion with explicit input sizes	2411.298 ms	505.671 ms	-79.6%
Unix / SQL Server 2022	1.2-million-row fetching	5048.741 ms	3496.130 ms	-30.3%
Unix / SQL Server 2025	Insertion with explicit input sizes	2328.064 ms	428.398 ms	-80.4%
Unix / SQL Server 2025	1.2-million-row fetching	5284.211 ms	3450.084 ms	-34.0%

Coverage: 2 of 2 environments completed. Advisory result; does not block merging.

Environment	Status
Unix / SQL Server 2022	Completed
Unix / SQL Server 2025	Completed

Affected phases and call counts

Phase times are inclusive diagnostics and must not be added together. They identify where measured time changed, not why it changed.

Unix / SQL Server 2022

Insertion with explicit input sizes: py::execute::cpp_call -35.979 ms; ddbc::SQLExecute_wrap -35.461 ms; ddbc::BindParameters -9.503 ms.
1.2-million-row fetching: py::fetchall::row_wrap -1582.804 ms; ddbc::FetchAll_wrap -2.772 ms; ddbc::FetchBatchData -2.742 ms.

Unix / SQL Server 2025

Insertion with explicit input sizes: py::execute::cpp_call -39.267 ms; ddbc::SQLExecute_wrap -38.696 ms; ddbc::BindParameters -5.345 ms.
1.2-million-row fetching: py::fetchall::row_wrap -1810.841 ms; ddbc::FetchBatchData::construct_rows -3.903 ms; py::fetchall::cpp_call -2.775 ms.

All database tasks and timings

Unix / SQL Server 2022

Database task	Before	After	Paired change	Result
Connection opening	10.925 ms	10.990 ms	+2.0%	no signal
SELECT queries	1.275 ms	1.130 ms	-12.7%	no signal
Row insertion	36.756 ms	35.460 ms	-2.1%	no signal
Executemany inserts	160.941 ms	162.738 ms	+1.6%	no signal
Fetch-all queries	175.299 ms	141.961 ms	-17.6%	no signal
Row-by-row fetching	60.657 ms	57.011 ms	-5.9%	no signal
Batched row fetching	166.519 ms	143.123 ms	-14.5%	no signal
Transaction commit and rollback	119.579 ms	117.539 ms	-2.0%	no signal
Arrow row fetching	105.969 ms	96.170 ms	-7.9%	no signal
100,000-row insertion	457.800 ms	446.350 ms	-2.7%	no signal
Row fetching in batches of 100	225.292 ms	196.418 ms	-14.3%	no signal
Row fetching in batches of 10,000	185.132 ms	164.188 ms	-11.0%	no signal
Repeated positional queries	43.427 ms	42.910 ms	-1.0%	no signal
Repeated named-parameter queries	45.771 ms	45.653 ms	+0.2%	no signal
Legacy 100,000-row insertion	356.290 ms	358.249 ms	-0.2%	no signal
Insertion with explicit input sizes	2411.298 ms	505.671 ms	-79.6%	consistent improvement
Joined aggregation queries	177.387 ms	179.804 ms	+0.7%	no signal
Large joined-result fetching	209.943 ms	200.717 ms	-3.6%	no signal
1.2-million-row fetching	5048.741 ms	3496.130 ms	-30.3%	consistent improvement
Common table expression queries	5.448 ms	5.447 ms	-1.4%	no signal

Unix / SQL Server 2025

Database task	Before	After	Paired change	Result
Connection opening	95.121 ms	96.329 ms	+0.1%	no signal
SELECT queries	1.162 ms	1.073 ms	-6.3%	no signal
Row insertion	31.493 ms	31.860 ms	+1.2%	no signal
Executemany inserts	136.383 ms	132.519 ms	-4.6%	no signal
Fetch-all queries	167.269 ms	134.834 ms	-17.2%	no signal
Row-by-row fetching	52.529 ms	49.629 ms	-4.8%	no signal
Batched row fetching	151.910 ms	132.099 ms	-12.6%	no signal
Transaction commit and rollback	102.192 ms	106.721 ms	+4.2%	no signal
Arrow row fetching	88.260 ms	90.731 ms	+1.9%	no signal
100,000-row insertion	394.324 ms	398.276 ms	-1.5%	no signal
Row fetching in batches of 100	196.767 ms	172.517 ms	-12.6%	no signal
Row fetching in batches of 10,000	170.302 ms	155.479 ms	-10.7%	no signal
Repeated positional queries	38.226 ms	38.171 ms	-0.2%	no signal
Repeated named-parameter queries	40.615 ms	40.469 ms	-0.4%	no signal
Legacy 100,000-row insertion	304.356 ms	311.129 ms	+2.0%	no signal
Insertion with explicit input sizes	2328.064 ms	428.398 ms	-80.4%	consistent improvement
Joined aggregation queries	161.639 ms	166.686 ms	+3.4%	no signal
Large joined-result fetching	205.818 ms	191.456 ms	-6.7%	no signal
1.2-million-row fetching	5284.211 ms	3450.084 ms	-34.0%	consistent improvement
Common table expression queries	5.262 ms	5.314 ms	+0.7%	no signal

Build, commits and measurement details

ADO build 177007

PR head: e1141c58ecacb6c9ede12adf31f9886f847946d4
Base: f3e34e66bca6d6f45d7a2cbea070c40ebe4ba194
Measured merge: 3b24afef89ae57daad8c92ad9bec71b483a885c7

• Unix / SQL Server 2022: Python 3.12.3, x86_64, SQL 16.0.4295.3; 5 paired comparisons and 1 warmup.
• Unix / SQL Server 2025: Python 3.12.3, x86_64, SQL 17.0.5005.3; 5 paired comparisons and 1 warmup.

A consistent change requires more than 20% median paired movement, at least 1 ms between the median runtimes, and at least 80% of pairs exceeding the relative threshold in the same direction. A slowdown without enough pair agreement is reported as inconsistent.

The displayed change is the median of paired before-and-after ratios. It is not recalculated from the two displayed median runtimes.

Both revisions use profiling-enabled builds on the same agent and database, with alternating order and discarded warmups. Results are diagnostic and do not represent production-wheel latency.

Raw samples and logs are attached to the ADO run as profiler-* artifacts.

[Copilot]

🟢 Approval recommended

No unresolved issues; the change is limited to a non-rendered README marker.

Pull request overview

Adds an invisible README marker to validate the profiler report control path without changing product code.

Changes:

• Adds an HTML comment canary to README.md.

File summaries

File	Description
README.md	Adds the invisible profiler control marker.

Review details

• Files reviewed: 1/1 changed files
• Comments generated: 0
• Review effort level: Lite

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[github-actions]

📊 Code Coverage Report

🔥 Diff Coverage 93%

🎯 Overall Coverage 84%

📈 Total Lines Covered: 8767 out of 10412 📁 Project: mssql-python

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Diff Coverage

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

• mssql_python/connection.py (100%)
• mssql_python/cursor.py (100%)
• mssql_python/pybind/ddbc_bindings.cpp (83.3%): Missing lines 3634-3636,3650-3652,3655
• mssql_python/row.py (100%)

Summary

• Total: 103 lines
• Missing: 7 lines
• Coverage: 93%

mssql_python/pybind/ddbc_bindings.cpp

Lines 3630-3640

  3630             case SQL_SMALLINT: {
  3631                 SQLSMALLINT smallIntValue;
  3632                 SQLLEN indicator = 0;
  3633                 ret = SQLGetData_ptr(hStmt, i, SQL_C_SHORT, &smallIntValue, 0, &indicator);
! 3634                 if (SQL_SUCCEEDED(ret) && indicator == SQL_NULL_DATA) {
! 3635                     row.append(py::none());
! 3636                     break;
  3637                 }
  3638                 if (SQL_SUCCEEDED(ret)) {
  3639                     row.append(static_cast<int>(smallIntValue));
  3640                 } else {

---

Lines 3646-3659

  3646                 break;
  3647             }
  3648             case SQL_REAL: {
  3649                 SQLREAL realValue;
! 3650                 SQLLEN indicator = 0;
! 3651                 ret = SQLGetData_ptr(hStmt, i, SQL_C_FLOAT, &realValue, 0, &indicator);
! 3652                 if (SQL_SUCCEEDED(ret) && indicator == SQL_NULL_DATA) {
  3653                     row.append(py::none());
  3654                     break;
! 3655                 }
  3656                 if (SQL_SUCCEEDED(ret)) {
  3657                     row.append(realValue);
  3658                 } else {
  3659                     LOG("SQLGetData: Error retrieving SQL_REAL for column %d - "

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📋 Files Needing Attention

📉 Files with overall lowest coverage (click to expand)

mssql_python.pybind.performance_counter.hpp: 0.7%
mssql_python.pybind.logger_bridge.cpp: 57.9%
mssql_python.pybind.ddbc_bindings.h: 64.1%
mssql_python.pybind.logger_bridge.hpp: 70.8%
mssql_python.pybind.ddbc_bindings.cpp: 78.5%
mssql_python.pybind.connection.connection_pool.cpp: 82.3%
mssql_python.pybind.connection.connection.cpp: 82.5%
mssql_python.logging.py: 86.2%
mssql_python.pooling.py: 90.1%
mssql_python.pybind.py_type_cache.hpp: 91.6%

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🔗 Quick Links

⚙️ Build Summary	📋 Coverage Details
View Azure DevOps Build	Browse Full Coverage Report

[Copilot]

🟢 Approval recommended

No unresolved issues were identified.

Review details

• Files reviewed: 1/1 changed files
• Comments generated: 0 new
• Review effort level: Lite

[Copilot]

Copilot review overview

🟢 Approval recommended

No unresolved review issues were identified.

Review effort: Lite
Findings: None

Resolved since last review (1)

• Remove unconditional 5 ms delay from parameterized SELECTs

[Copilot]

Copilot review overview

🟡 Changes recommended

The PR scope does not match its stated canary purpose, and Row changes may break existing public API behavior.

Get a fresh assessment by requesting another Copilot review.

Review effort: Lite
Findings: 1

Open (1)

• PR scope includes unintended production behavior changes · New

[Copilot]

Copilot review overview

🟡 Changes recommended

Unresolved API compatibility, fetch-path performance, report coverage, and scope issues remain.

Get a fresh assessment by requesting another Copilot review.

Review effort: Lite
Findings: 1 · 1

Open (2)

• slots breaks Row metadata and weak-reference support · New
• PR scope includes unintended production behavior changes

[Copilot]

Copilot review overview

🟡 Changes recommended

The scope is not README-only, report coverage is incomplete, and the Row changes may break public API compatibility.

Get a fresh assessment by requesting another Copilot review.

Review effort: Lite
Findings: 1 · 1 · 1

Open (3)

• slots breaks Row metadata and weak-reference support
• Coverage badge cannot report five environments from two configured legs · New
• PR scope includes unintended production behavior changes

[Copilot]

Copilot review overview

🔵 Needs a closer look

Address the public Row API break, native reference leak, and mismatches between the stated canary scope and CI coverage.

Review effort: Lite
Findings: 1 · 1 · 1

Open (3)

• slots breaks Row metadata and weak-reference support
• Coverage badge cannot report five environments from two configured legs
• PR scope includes unintended production behavior changes

[Copilot]

Copilot review overview

🟡 Changes recommended

Critical CI coverage changes and unresolved fetch-performance and Row compatibility regressions must be addressed.

Get a fresh assessment by requesting another Copilot review.

Review effort: Lite
Findings: 2 · 1 · 1

Open (4)

• CodeQL is unconditionally disabled · New
• slots breaks Row metadata and weak-reference support
• Coverage badge cannot report five environments from two configured legs
• PR scope includes unintended production behavior changes

[Copilot]

Copilot review overview

🔵 Needs a closer look

Broad CI coverage is disabled, and the implementation scope conflicts with the README-only canary description.

Review effort: Lite
Findings: 2 · 1 · 1

Open (4)

• CodeQL is unconditionally disabled
• slots breaks Row metadata and weak-reference support
• Coverage badge cannot report five environments from two configured legs
• PR scope includes unintended production behavior changes