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Fix Rule 3: CouldNotGenerateValidParallelPlan stays Warning #192

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Merged
erikdarlingdata merged 1 commit into from
Apr 7, 2026
Merged

Fix Rule 3: CouldNotGenerateValidParallelPlan stays Warning #192

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8 changes: 5 additions & 3 deletions src/PlanViewer.Core/Services/PlanAnalyzer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -141,14 +141,16 @@
_ => stmt.NonParallelPlanReason
};

// Only warn (not info) when the user explicitly forced serial execution
var isExplicit = stmt.NonParallelPlanReason is "MaxDOPSetToOne" or "QueryHintNoParallelSet";
// Warn when the user forced serial or something in the query blocks parallelism.
// Info only for passive reasons (cost below threshold, edition limitation).
var isActionable = stmt.NonParallelPlanReason is "MaxDOPSetToOne"
or "QueryHintNoParallelSet" or "CouldNotGenerateValidParallelPlan";

stmt.PlanWarnings.Add(new PlanWarning
{
WarningType = "Serial Plan",
Message = $"Query running serially: {reason}.",
Severity = isExplicit ? PlanWarningSeverity.Warning : PlanWarningSeverity.Info
Severity = isActionable ? PlanWarningSeverity.Warning : PlanWarningSeverity.Info
});
}

Expand Down Expand Up @@ -984,7 +986,7 @@
// Rule 28: Row Count Spool — NOT IN with nullable column
// Pattern: Row Count Spool with high rewinds, child scan has IS NULL predicate,
// and statement text contains NOT IN
if (!cfg.IsRuleDisabled(28) && node.PhysicalOp.Contains("Row Count Spool"))

Check warning on line 989 in src/PlanViewer.Core/Services/PlanAnalyzer.cs

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Dereference of a possibly null reference.

Check warning on line 989 in src/PlanViewer.Core/Services/PlanAnalyzer.cs

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GitHub Actions / build-and-test 

Dereference of a possibly null reference.
{
var rewinds = node.HasActualStats ? (double)node.ActualRewinds : node.EstimateRewinds;
if (rewinds > 10000 && HasNotInPattern(node, stmt))
Expand Down
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