avoid Lock acquisition on ErrorCount/WarningCount when no errors exist#4157
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paulmedynski merged 4 commits intoMay 14, 2026
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- _hasErrorOrWarning marked volatile (line 278) -- the field was already read without a lock at line 1212, so this makes the existing pattern and the new fast paths correct across all memory models.
- ErrorCount fast path -- returns 0 immediately when _hasErrorOrWarning is false, skipping the lock. Safe because _hasErrorOrWarning is only set to false under the lock when _errors is also nulled.
- WarningCount fast path -- same treatment.
1. _hasErrorOrWarning marked volatile (line 278) -- the field was already read without a lock at line 1212, so this makes the existing pattern and the new fast paths correct across all memory models. 2. ErrorCount fast path -- returns 0 immediately when _hasErrorOrWarning is false, skipping the lock. Safe because _hasErrorOrWarning is only set to false under the lock when _errors is also nulled. 3. WarningCount fast path -- same treatment.
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Pull request overview
This PR optimizes error/warning counting on TdsParserStateObject by adding a lock-free fast path when no errors/warnings are present, using a volatile flag to make the existing lock-free reads safe across memory models.
Changes:
- Mark
_hasErrorOrWarningasvolatileto support safe lock-free reads. - Add early-return fast paths in
ErrorCountandWarningCountwhen_hasErrorOrWarningisfalse.
…arserStateObject.cs Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
…arserStateObject.cs Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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Have a look at the linked compiler errors.
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Codecov Report✅ All modified and coverable lines are covered by tests.
Additional details and impacted files@@ Coverage Diff @@
## main #4157 +/- ##
==========================================
- Coverage 74.37% 64.46% -9.92%
==========================================
Files 279 270 -9
Lines 42983 65785 +22802
==========================================
+ Hits 31969 42406 +10437
- Misses 11014 23379 +12365
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LGTM — clean optimization, volatile makes the existing lock-free read correct.
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#4157) * avoid Lock acquisition on ErrorCount/WarningCount when no errors exist 1. _hasErrorOrWarning marked volatile (line 278) -- the field was already read without a lock at line 1212, so this makes the existing pattern and the new fast paths correct across all memory models. 2. ErrorCount fast path -- returns 0 immediately when _hasErrorOrWarning is false, skipping the lock. Safe because _hasErrorOrWarning is only set to false under the lock when _errors is also nulled. 3. WarningCount fast path -- same treatment. * Update src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> * Update src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> * Update TdsParserStateObject.cs --------- Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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