Optimization: Use Environment.TickCount for SqlStatistics execution timing

[SAY14489]

Description

This change optimizes the performance of SQL execution timing by replacing expensive DateTime operations with lightweight Environment.TickCount calls in SqlStatistics. The optimization targets the RequestExecutionTimer() and ReleaseAndUpdateExecutionTimer() methods, which are frequently called during database operations. This issue was exposed by profilers which showed that these two calling methods made up a significant portion of DateTime.UtcNow CPU usage.

Performance improvement:

Method	Mean	Error	StdDev	Ratio	RatioSD	Allocated	Alloc Ratio
DateTimeUtcNowToFileTimeUtc	57.243 ns	0.9307 ns	0.8250 ns	1.00	0.02	-	NA
EnvironmentTickCount	1.272 ns	0.0533 ns	0.1328 ns	0.02	0.00	-	NA

^ Done Through BenchmarkDotNet
Benchmarking shows an approximately 55x performance improvement (from ~57ns to ~1ns per timing operation) while maintaining adequate accuracy for database operation monitoring.

Changes made:

• Added ADP.FastTimerCurrent() method using Environment.TickCount
• Modified SqlStatistics execution timing methods to use the optimized timer
• Implemented wraparound handling for 32-bit integer overflow
• Updated timing units to maintain consistency with existing millisecond reporting

Backwards compatibility:

Fully maintained. All existing APIs, return values, and units remain unchanged. The optimization is internal implementation only.

Scope:

This change specifically optimizes execution timing measurement without affecting timeout logic or other timing-dependent functionality in the codebase.

Issues

Performance optimization. Addresses inefficient use of DateTime.UtcNow.ToFileTimeUtc() for high-frequency elapsed time measurements.

Testing

Manual testing performed:

• Created test application measuring timing accuracy across different durations (100ms to 2000ms)
• Verified timing accuracy using Stopwatch as baseline for actual elapsed time measurement and compared against DateTime.UtcNow.ToFileTimeUtc()
• Confirmed proper accumulation of execution times across multiple measurement periods

Accuracy results:

Testing showed the TickCount optimization maintains acceptable accuracy for duration timing, with error rates under 3% compared to StopWatch baseline for operations lasting 100ms or longer. It is a slight loss in accuracy compared to DateTime.UtcNow.ToFileTimeUtc(), which I believe is due to the lower precision, but for the use case and performance improvement of 55x, it seems like a worthwhile switch.

[Copilot]

Pull Request Overview

This PR optimizes SQL execution timing performance by replacing expensive DateTime.UtcNow operations with lightweight Environment.TickCount calls in SqlStatistics. The change provides approximately 55x performance improvement (from ~57ns to ~1ns per timing operation) while maintaining adequate accuracy for database operation monitoring.

Key changes:

• Added ADP.FastTimerCurrent() method using Environment.TickCount for high-frequency timing operations
• Modified SqlStatistics execution timing to use nullable timestamp and wraparound handling for 32-bit integer overflow
• Updated timing units in dictionary output to maintain consistency with existing millisecond reporting

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlStatistics.cs	Modified execution timing implementation to use nullable timestamps, added wraparound logic, and updated dictionary output format
src/Microsoft.Data.SqlClient/src/Microsoft/Data/Common/AdapterUtil.cs	Added FastTimerCurrent() method using Environment.TickCount for optimized timing operations

[paulmedynski]

/azp run

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Azure Pipelines successfully started running 2 pipeline(s).

[paulmedynski]

Questions about the wrapping algorithms and unit tests.

[SAY14489]

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[azure-pipelines]

Commenter does not have sufficient privileges for PR 3609 in repo dotnet/SqlClient

[paulmedynski]

Looks great!

[paulmedynski]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[paulmedynski]

@SAY14489 - Thank you for the great PR, especially your first contribution. Performance improvements like this that are isolated and easy to verify are always welcome!

[samsharma2700]

Great work!

[SAY14489]

Great work!

I’m trying to complete this PR. I just synced this branch with the up to date main since I couldn’t see the merge option, could you please start a pipeline run to fulfill the requirements? Thank You!

[paulmedynski]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[codecov]

Codecov Report

❌ Patch coverage is 81.81818% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 62.50%. Comparing base (fd16c6d) to head (6058ca0).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...ient/src/Microsoft/Data/SqlClient/SqlStatistics.cs	77.77%	2 Missing ⚠️

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HEAD has 4 uploads less than BASE

Flag	BASE (fd16c6d)	HEAD (6058ca0)
netfx	2	1
netcore	2	1
addons	2	0

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3609      +/-   ##
==========================================
- Coverage   70.67%   62.50%   -8.18%     
==========================================
  Files         277      271       -6     
  Lines       61686    61373     -313     
==========================================
- Hits        43598    38360    -5238     
- Misses      18088    23013    +4925     

Flag	Coverage Δ
addons	?
netcore	67.67% <81.81%> (-5.70%)	⬇️
netfx	60.86% <81.81%> (-8.72%)	⬇️

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