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Rule 15: Restore join ancestor check alongside Merge Interval #350

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Merged
erikdarlingdata merged 1 commit into from
Feb 27, 2026
Merged

Rule 15: Restore join ancestor check alongside Merge Interval #350

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23 changes: 20 additions & 3 deletions Dashboard/Services/PlanAnalyzer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -399,15 +399,16 @@
}
}

// Rule 15: Join OR clause (Concatenation + Constant Scan under Merge Interval)
// Pattern: Merge Interval → TopN Sort → Concatenation → Constant Scans
// Rule 15: Join OR clause (Concatenation + Constant Scan under join/Merge Interval)
// Best signal: Merge Interval → TopN Sort → Concatenation → Constant Scans
// Also fires under a join ancestor (broader catch)
if (node.PhysicalOp == "Concatenation")
{
var constantScanBranches = node.Children
.Count(c => c.PhysicalOp == "Constant Scan" ||
c.Children.Any(gc => gc.PhysicalOp == "Constant Scan"));

if (constantScanBranches >= 2 && HasMergeIntervalAncestor(node))
if (constantScanBranches >= 2 && (HasMergeIntervalAncestor(node) || HasJoinAncestor(node)))
{
node.Warnings.Add(new PlanWarning
{
Expand Down Expand Up @@ -463,7 +464,7 @@

// Rule 22: Table variables (Object name starts with @)
if (!string.IsNullOrEmpty(node.ObjectName) &&
node.ObjectName.Contains("@"))

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{
node.Warnings.Add(new PlanWarning
{
Expand Down Expand Up @@ -626,6 +627,22 @@
return false;
}

/// <summary>
/// Checks whether a node has any join ancestor.
/// </summary>
private static bool HasJoinAncestor(PlanNode node)
{
var ancestor = node.Parent;
while (ancestor != null)
{
if (ancestor.LogicalOp != null &&
ancestor.LogicalOp.Contains("Join", StringComparison.OrdinalIgnoreCase))
return true;
ancestor = ancestor.Parent;
}
return false;
}

/// <summary>
/// Finds Sort and Hash Match operators in the tree that consume memory.
/// </summary>
Expand Down
23 changes: 20 additions & 3 deletions Lite/Services/PlanAnalyzer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -399,15 +399,16 @@
}
}

// Rule 15: Join OR clause (Concatenation + Constant Scan under Merge Interval)
// Pattern: Merge Interval → TopN Sort → Concatenation → Constant Scans
// Rule 15: Join OR clause (Concatenation + Constant Scan under join/Merge Interval)
// Best signal: Merge Interval → TopN Sort → Concatenation → Constant Scans
// Also fires under a join ancestor (broader catch)
if (node.PhysicalOp == "Concatenation")
{
var constantScanBranches = node.Children
.Count(c => c.PhysicalOp == "Constant Scan" ||
c.Children.Any(gc => gc.PhysicalOp == "Constant Scan"));

if (constantScanBranches >= 2 && HasMergeIntervalAncestor(node))
if (constantScanBranches >= 2 && (HasMergeIntervalAncestor(node) || HasJoinAncestor(node)))
{
node.Warnings.Add(new PlanWarning
{
Expand Down Expand Up @@ -463,7 +464,7 @@

// Rule 22: Table variables (Object name starts with @)
if (!string.IsNullOrEmpty(node.ObjectName) &&
node.ObjectName.Contains("@"))

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{
node.Warnings.Add(new PlanWarning
{
Expand Down Expand Up @@ -626,6 +627,22 @@
return false;
}

/// <summary>
/// Checks whether a node has any join ancestor.
/// </summary>
private static bool HasJoinAncestor(PlanNode node)
{
var ancestor = node.Parent;
while (ancestor != null)
{
if (ancestor.LogicalOp != null &&
ancestor.LogicalOp.Contains("Join", StringComparison.OrdinalIgnoreCase))
return true;
ancestor = ancestor.Parent;
}
return false;
}

/// <summary>
/// Finds Sort and Hash Match operators in the tree that consume memory.
/// </summary>
Expand Down
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