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Fix Rule 2: eager table spools no longer flagged as eager index spools #160

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Merged
erikdarlingdata merged 1 commit into from
Mar 30, 2026
Merged

Fix Rule 2: eager table spools no longer flagged as eager index spools #160

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2 changes: 1 addition & 1 deletion src/PlanViewer.Core/Services/PlanAnalyzer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -460,7 +460,7 @@

// Rule 2: Eager Index Spools — optimizer building temporary indexes on the fly
if (!cfg.IsRuleDisabled(2) && node.LogicalOp == "Eager Spool" &&
node.PhysicalOp.Contains("Spool", StringComparison.OrdinalIgnoreCase))
node.PhysicalOp.Contains("Index", StringComparison.OrdinalIgnoreCase))
{
var message = "SQL Server is building a temporary index in TempDB at runtime because no suitable permanent index exists. This is expensive — it builds the index from scratch on every execution. Create a permanent index on the underlying table to eliminate this operator entirely.";
if (!string.IsNullOrEmpty(node.SuggestedIndex))
Expand Down Expand Up @@ -949,7 +949,7 @@
// 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 952 in src/PlanViewer.Core/Services/PlanAnalyzer.cs

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GitHub Actions / build-and-test 

Dereference of a possibly null reference.

Check warning on line 952 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))
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11 changes: 11 additions & 0 deletions tests/PlanViewer.Core.Tests/PlanAnalyzerTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,17 @@ public void Rule02_EagerIndexSpool_DetectedInLazySpoolPlan()
Assert.Contains(warnings, w => w.Message.Contains("temporary index in TempDB"));
}

[Fact]
public void Rule02_EagerIndexSpool_NotFiredForEagerTableSpool()
{
// Plan with Eager Table Spool (PhysicalOp="Table Spool", LogicalOp="Eager Spool")
// should NOT trigger the Eager Index Spool warning
var plan = PlanTestHelper.LoadAndAnalyze("eager_table_spool_plan.sqlplan");
var warnings = PlanTestHelper.WarningsOfType(plan, "Eager Index Spool");

Assert.Empty(warnings);
}

// ---------------------------------------------------------------
// Rule 3: Serial Plan
// ---------------------------------------------------------------
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