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Release v1.7.0 — wait stats as warnings #245

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Merged
erikdarlingdata merged 1 commit into from
Apr 21, 2026
Merged

Release v1.7.0 — wait stats as warnings #245

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2 changes: 1 addition & 1 deletion src/PlanViewer.App/PlanViewer.App.csproj
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@
<ApplicationManifest>app.manifest</ApplicationManifest>
<ApplicationIcon>EDD.ico</ApplicationIcon>
<AvaloniaUseCompiledBindingsByDefault>true</AvaloniaUseCompiledBindingsByDefault>
<Version>1.6.0</Version>
<Version>1.7.0</Version>
<Authors>Erik Darling</Authors>
<Company>Darling Data LLC</Company>
<Product>Performance Studio</Product>
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63 changes: 63 additions & 0 deletions src/PlanViewer.Core/Services/BenefitScorer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -38,10 +38,73 @@ public static void Score(ParsedPlan plan)

if (stmt.WaitStats.Count > 0 && stmt.QueryTimeStats != null)
ScoreWaitStats(stmt);

if (stmt.WaitStats.Count > 0)
EmitWaitStatWarnings(stmt);
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@erikdarlingdata erikdarlingdata Apr 21, 2026

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EmitWaitStatWarnings runs even when QueryTimeStats == null (line 39's ScoreWaitStats is skipped in that case). With no WaitBenefits populated, benefitByType is empty and every wait gets severity = Info regardless of how dominant the wait is. That may be intentional (estimated/incomplete plans don't have elapsed to score against) but worth confirming — if it is, a one-line comment here saying "no QueryTimeStats → all severities pinned to Info" would save the next reader a trip through the lookup chain.

Also: the two adjacent if (stmt.WaitStats.Count > 0) blocks can collapse into a single guarded block, slightly cheaper and reads more clearly:

if (stmt.WaitStats.Count > 0)
{
    if (stmt.QueryTimeStats != null) ScoreWaitStats(stmt);
    EmitWaitStatWarnings(stmt);
}

Generated by Claude Code

}
}
}

/// <summary>
/// Emits a PlanWarning per wait stat entry, merging the per-wait benefit %
/// from ScoreWaitStats with the descriptive content from WaitStatsKnowledge.
/// The existing wait-stats chart/card stays as a complementary view.
/// </summary>
private static void EmitWaitStatWarnings(PlanStatement stmt)
{
// Lookup benefit % by wait type (populated by ScoreWaitStats)
var benefitByType = new Dictionary<string, double>(StringComparer.OrdinalIgnoreCase);
foreach (var wb in stmt.WaitBenefits)
benefitByType[wb.WaitType] = wb.MaxBenefitPercent;

foreach (var wait in stmt.WaitStats)
{
if (wait.WaitTimeMs <= 0) continue;
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@erikdarlingdata erikdarlingdata Apr 21, 2026

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The only filter on emitting a warning is WaitTimeMs <= 0. Every nonzero wait — including 1ms SOS_SCHEDULER_YIELD chatter on a 30s query — becomes a first-class PlanWarning in the expander. On busy real-world plans (10–30 distinct wait types) this can flood the Plan Warnings UI with low-signal Info rows and make the genuinely actionable ones harder to find.

Consider a minimum-relevance threshold, e.g. skip emission if wait.WaitTimeMs / elapsedMs < 0.005 and benefitPct < 1, or drop pure Info waits below some absolute floor.

Generated by Claude Code


var entry = WaitStatsKnowledge.Lookup(wait.WaitType);
double? benefitPct = benefitByType.TryGetValue(wait.WaitType, out var b) ? b : null;

var msg = new System.Text.StringBuilder();
msg.Append(wait.WaitType).Append(": ").Append(entry.Description);
msg.Append(" Observed ").Append(wait.WaitTimeMs.ToString("N0")).Append(" ms");
if (wait.WaitCount > 0)
msg.Append(" across ").Append(wait.WaitCount.ToString("N0")).Append(" wait").Append(wait.WaitCount == 1 ? "" : "s");
msg.Append('.');

if (entry.ShowEffectiveLatency && wait.WaitCount > 0)
{
var effLatency = (double)wait.WaitTimeMs / wait.WaitCount;
msg.Append(" Effective latency: ")
.Append(FormatLatency(effLatency))
.Append(" per wait.");
}

var severity = benefitPct switch
{
>= 50 => PlanWarningSeverity.Critical,
>= 10 => PlanWarningSeverity.Warning,
_ => PlanWarningSeverity.Info,
};

stmt.PlanWarnings.Add(new PlanWarning
{
WarningType = "Wait: " + wait.WaitType,
Message = msg.ToString(),
Severity = severity,
MaxBenefitPercent = benefitPct,
ActionableFix = entry.HowToFix
});
}
}

private static string FormatLatency(double ms)
{
if (ms >= 1000) return $"{ms / 1000:N2} s";
if (ms >= 10) return $"{ms:N0} ms";
if (ms >= 1) return $"{ms:N1} ms";
return $"{ms * 1000:N0} µs";
}

private static void ScoreStatementWarnings(PlanStatement stmt)
{
var elapsedMs = stmt.QueryTimeStats?.ElapsedTimeMs ?? 0;
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