[5.1] Optimization: Use Environment.TickCount for SqlStatistics execution timing

[cheenamalhotra]

Ports #3609 to release/5.1 branch

Closes #3763

[Copilot]

Pull request overview

This PR optimizes SQL execution timing statistics by replacing the DateTime-based timer with Environment.TickCount for measuring ExecutionTime. This change reduces overhead while maintaining accuracy for performance statistics. The PR ports optimization work from #3609 to the release/5.1 branch.

Key changes:

• Replaced DateTime.UtcNow.ToFileTimeUtc() with Environment.TickCount for ExecutionTime measurements
• Added wraparound-safe elapsed time calculation to handle TickCount rolling over every ~24.9 days
• Removed unreliable timing comparison assertions that could fail due to timing precision differences

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
AdapterUtil.cs	Added FastTimerCurrent() to return Environment.TickCount and CalculateTickCountElapsed() to calculate elapsed time with wraparound handling
SqlStatistics.cs	Changed _startExecutionTimestamp to nullable long, updated ExecutionTime accumulation to use TickCount directly (already in milliseconds), removed TimerToMilliseconds conversion
TickCountElapsedTest.cs	New test file validating wraparound handling for TickCount elapsed time calculations
Microsoft.Data.SqlClient.Tests.csproj	Registered the new TickCountElapsedTest.cs test file
CopyAllFromReader.cs	Removed assertions comparing ConnectionTime/ExecutionTime/NetworkServerTime as these are no longer reliable with different timing mechanisms

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

[Copilot]

The test is duplicating the implementation logic instead of testing the actual ADP.CalculateTickCountElapsed method. This test should call ADP.CalculateTickCountElapsed directly to validate the real implementation, not a copy of it. Consider changing this to:

internal static uint CalculateTickCountElapsed(long startTick, long endTick) => ADP.CalculateTickCountElapsed(startTick, endTick);

[paulmedynski]

Agreed.

[codecov]

Codecov Report

❌ Patch coverage is 81.81818% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 70.76%. Comparing base (cc5c81a) to head (1f4edde).

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

Additional details and impacted files

@@               Coverage Diff               @@
##           release/5.1    #3831      +/-   ##
===============================================
- Coverage        71.51%   70.76%   -0.75%     
===============================================
  Files              293      293              
  Lines            61928    61931       +3     
===============================================
- Hits             44289    43828     -461     
- Misses           17639    18103     +464     

Flag	Coverage Δ
addons	92.38% <ø> (ø)
netcore	75.00% <81.81%> (-0.03%)	⬇️
netfx	68.78% <81.81%> (-1.14%)	⬇️

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[paulmedynski]

I agree with Copilot.