Fix #283: columnstore icon routing + Parallelism subtype overlay

src/PlanViewer.App/Controls/PlanViewerControl.axaml.cs

@@ -495,13 +495,45 @@ private Border CreateNodeVisual(PlanNode node, int totalWarningCount = -1)
         var iconBitmap = IconHelper.LoadIcon(node.IconName);
         if (iconBitmap != null)
         {
-            iconRow.Children.Add(new Image
+            var iconImage = new Image
             {
                 Source = iconBitmap,
                 Width = 32,
                 Height = 32,
                 Margin = new Thickness(0, 0, 0, 2)
-            });
+            };
+
+            // Distinguish Parallelism subtypes (Repartition / Distribute / Gather Streams)
+            // by overlaying a small letter on the shared parallelism.png icon.
+            var parallelismGlyph = GetParallelismGlyph(node);
+            if (parallelismGlyph != null)
+            {
+                var iconGrid = new Grid { Margin = new Thickness(0, 0, 0, 2) };
+                iconGrid.Children.Add(iconImage);
+                iconImage.Margin = default;
+                iconGrid.Children.Add(new Border
+                {
+                    Width = 14, Height = 14,
+                    HorizontalAlignment = HorizontalAlignment.Right,
+                    VerticalAlignment = VerticalAlignment.Bottom,
+                    Background = new SolidColorBrush(Color.FromRgb(0x33, 0x33, 0x33)),
+                    CornerRadius = new CornerRadius(7),
+                    Child = new TextBlock
+                    {
+                        Text = parallelismGlyph,
+                        FontSize = 9,
+                        FontWeight = FontWeight.Bold,
+                        Foreground = Brushes.White,
+                        HorizontalAlignment = HorizontalAlignment.Center,
+                        VerticalAlignment = VerticalAlignment.Center
+                    }
+                });
+                iconRow.Children.Add(iconGrid);
+            }
+            else
+            {
+                iconRow.Children.Add(iconImage);
+            }
         }
 
         // Warning indicator badge (orange triangle with !)
@@ -3062,6 +3094,24 @@ private void UpdateInsightsHeader()
         InsightsHeader.Text = "  Plan Insights";
     }
 
+    /// <summary>
+    /// For Parallelism nodes, returns a single-letter glyph distinguishing
+    /// the three subtypes: R(epartition) / D(istribute) / G(ather) Streams.
+    /// Returns null for non-parallelism operators.
+    /// </summary>
+    private static string? GetParallelismGlyph(PlanNode node)
+    {
+        if (!string.Equals(node.PhysicalOp, "Parallelism", StringComparison.Ordinal))
+            return null;
+        return node.LogicalOp switch
+        {
+            "Repartition Streams" => "R",
+            "Distribute Streams" => "D",
+            "Gather Streams" => "G",
+            _ => null
+        };
+    }
+
     private static string GetWaitCategory(string waitType)
     {
         if (waitType.StartsWith("SOS_SCHEDULER_YIELD") ||

src/PlanViewer.Core/Services/PlanIconMapper.cs

@@ -178,9 +178,36 @@ public static class PlanIconMapper
 
     /// <summary>
     /// Returns the icon file name (without extension) for a given physical operator.
+    /// When <paramref name="storageType"/> is "ColumnStore" on a *Index Scan,
+    /// routes to the columnstore variant.
     /// </summary>
-    public static string GetIconName(string physicalOp)
+    public static string GetIconName(string physicalOp, string? storageType = null)
     {
+        // Columnstore scans surface as PhysicalOp="Clustered Index Scan" / "Index Scan"
+        // with Storage="ColumnStore" on the Object element. Route to the columnstore icon.
+        if (string.Equals(storageType, "ColumnStore", StringComparison.OrdinalIgnoreCase))
+        {
+            switch (physicalOp)
+            {
+                case "Clustered Index Scan":
+                case "Index Scan":
+                case "Columnstore Index Scan":
+                    return "columnstore_index_scan";
+                case "Clustered Index Delete":
+                case "Index Delete":
+                    return "columnstore_index_delete";
+                case "Clustered Index Insert":
+                case "Index Insert":
+                    return "columnstore_index_insert";
+                case "Clustered Index Update":
+                case "Index Update":
+                    return "columnstore_index_update";
+                case "Clustered Index Merge":
+                case "Index Merge":
+                    return "columnstore_index_merge";
+            }
+        }
+
         if (IconMap.TryGetValue(physicalOp, out var iconName))
             return iconName;
 

src/PlanViewer.Core/Services/ShowPlanParser.cs

@@ -667,8 +667,9 @@ private static PlanNode ParseRelOp(XElement relOpEl)
         }
 
 
-        // Map to icon
-        node.IconName = PlanIconMapper.GetIconName(node.PhysicalOp);
+        // Icon mapping is deferred until after StorageType is parsed below,
+        // so columnstore scans (which surface as Clustered/Index Scan with
+        // Storage="ColumnStore") can be routed to the columnstore icon.
 
         // Handle operator-specific element
         var physicalOpEl = GetOperatorElement(relOpEl);
@@ -1368,6 +1369,11 @@ private static PlanNode ParseRelOp(XElement relOpEl)
             }
         }
 
+        // Map to icon — done here so columnstore scans (which surface as
+        // Clustered/Index Scan with Storage="ColumnStore") can be routed to
+        // the columnstore icon.
+        node.IconName = PlanIconMapper.GetIconName(node.PhysicalOp, node.StorageType);
+
         // Recurse into child RelOps
         foreach (var childRelOp in FindChildRelOps(relOpEl))
         {