Add before/after comparison mode for query grids (#687)

Dashboard/Controls/QueryPerformanceContent.xaml.cs

@@ -60,6 +60,9 @@ private static (DateTime start, DateTime end) GetSlicerTimeRange(
         /// <summary>Raised when a drill-down needs the parent to set custom time pickers. Args: (fromUtc, toUtc)</summary>
         public event Action<DateTime, DateTime>? DrillDownTimeRangeRequested;
 
+        /// <summary>Fired when the Queries sub-tab changes, so the global Compare dropdown can update.</summary>
+        public event Action? SubTabChanged;
+
         private CancellationTokenSource? _actualPlanCts;
 
         /// <summary>Cancels the in-flight actual plan execution, if any.</summary>
@@ -157,7 +160,14 @@ public QueryPerformanceContent()
             SetupChartSaveMenus();
             Loaded += OnLoaded;
             Unloaded += OnUnloaded;
-            SubTabControl.SelectionChanged += (s, e) => { if (e.Source == SubTabControl) _isDrillDownActive = false; };
+            SubTabControl.SelectionChanged += (s, e) =>
+            {
+                if (e.Source == SubTabControl)
+                {
+                    _isDrillDownActive = false;
+                    SubTabChanged?.Invoke();
+                }
+            };
             Helpers.ThemeManager.ThemeChanged += OnThemeChanged;
 
             _queryDurationHover = new Helpers.ChartHoverHelper(QueryPerfTrendsQueryChart, "ms/sec");
@@ -723,6 +733,140 @@ public void RefreshGridBindings()
         /// </summary>
         public void SelectSubTab(int index) => SubTabControl.SelectedIndex = index;
 
+        private (DateTime From, DateTime To)? _comparisonRange;
+
+        public void SetComparisonRange((DateTime From, DateTime To)? range)
+        {
+            _comparisonRange = range;
+        }
+
+        public async Task RefreshComparisonAsync()
+        {
+            if (_databaseService == null) return;
+
+            try
+            {
+                var currentEnd = _queryStatsToDate ?? DateTime.UtcNow;
+                var currentStart = _queryStatsFromDate ?? currentEnd.AddHours(-_queryStatsHoursBack);
+
+                await RefreshQueryStatsComparisonAsync(currentStart, currentEnd);
+                await RefreshProcStatsComparisonAsync(currentStart, currentEnd);
+                await RefreshQueryStoreComparisonAsync(currentStart, currentEnd);
+            }
+            catch (Exception ex)
+            {
+                _statusCallback?.Invoke($"Comparison failed: {ex.Message}");
+            }
+        }
+
+        private void SetQueryStatsComparisonMode(bool active, (DateTime From, DateTime To)? baselineRange = null)
+        {
+            QueryStatsDataGrid.Visibility = active ? System.Windows.Visibility.Collapsed : System.Windows.Visibility.Visible;
+            QueryStatsComparisonGrid.Visibility = active ? System.Windows.Visibility.Visible : System.Windows.Visibility.Collapsed;
+            QueryStatsComparisonBanner.Visibility = active ? System.Windows.Visibility.Visible : System.Windows.Visibility.Collapsed;
+
+            if (active && baselineRange.HasValue)
+            {
+                var from = baselineRange.Value.From.ToString("yyyy-MM-dd HH:mm");
+                var to = baselineRange.Value.To.ToString("yyyy-MM-dd HH:mm");
+                QueryStatsComparisonBanner.Text = $"Comparing against baseline: {from} \u2192 {to}";
+            }
+        }
+
+        private async Task RefreshQueryStatsComparisonAsync(DateTime currentStart, DateTime currentEnd)
+        {
+            if (_comparisonRange == null)
+            {
+                SetQueryStatsComparisonMode(false);
+                return;
+            }
+
+            SetQueryStatsComparisonMode(true, _comparisonRange);
+
+            var items = await _databaseService!.GetQueryStatsComparisonAsync(
+                currentStart, currentEnd,
+                _comparisonRange.Value.From, _comparisonRange.Value.To);
+
+            var sorted = items
+                .OrderBy(x => x.SortGroup)
+                .ThenByDescending(x => x.SortableDurationDelta)
+                .ToList();
+
+            QueryStatsComparisonGrid.ItemsSource = sorted;
+        }
+
+        private void SetProcStatsComparisonMode(bool active, (DateTime From, DateTime To)? baselineRange = null)
+        {
+            ProcStatsDataGrid.Visibility = active ? System.Windows.Visibility.Collapsed : System.Windows.Visibility.Visible;
+            ProcStatsComparisonGrid.Visibility = active ? System.Windows.Visibility.Visible : System.Windows.Visibility.Collapsed;
+            ProcStatsComparisonBanner.Visibility = active ? System.Windows.Visibility.Visible : System.Windows.Visibility.Collapsed;
+
+            if (active && baselineRange.HasValue)
+            {
+                var from = baselineRange.Value.From.ToString("yyyy-MM-dd HH:mm");
+                var to = baselineRange.Value.To.ToString("yyyy-MM-dd HH:mm");
+                ProcStatsComparisonBanner.Text = $"Comparing against baseline: {from} \u2192 {to}";
+            }
+        }
+
+        private async Task RefreshProcStatsComparisonAsync(DateTime currentStart, DateTime currentEnd)
+        {
+            if (_comparisonRange == null)
+            {
+                SetProcStatsComparisonMode(false);
+                return;
+            }
+
+            SetProcStatsComparisonMode(true, _comparisonRange);
+
+            var items = await _databaseService!.GetProcedureStatsComparisonAsync(
+                currentStart, currentEnd,
+                _comparisonRange.Value.From, _comparisonRange.Value.To);
+
+            var sorted = items
+                .OrderBy(x => x.SortGroup)
+                .ThenByDescending(x => x.SortableDurationDelta)
+                .ToList();
+
+            ProcStatsComparisonGrid.ItemsSource = sorted;
+        }
+
+        private void SetQueryStoreComparisonMode(bool active, (DateTime From, DateTime To)? baselineRange = null)
+        {
+            QueryStoreDataGrid.Visibility = active ? System.Windows.Visibility.Collapsed : System.Windows.Visibility.Visible;
+            QueryStoreComparisonGrid.Visibility = active ? System.Windows.Visibility.Visible : System.Windows.Visibility.Collapsed;
+            QueryStoreComparisonBanner.Visibility = active ? System.Windows.Visibility.Visible : System.Windows.Visibility.Collapsed;
+
+            if (active && baselineRange.HasValue)
+            {
+                var from = baselineRange.Value.From.ToString("yyyy-MM-dd HH:mm");
+                var to = baselineRange.Value.To.ToString("yyyy-MM-dd HH:mm");
+                QueryStoreComparisonBanner.Text = $"Comparing against baseline: {from} \u2192 {to}";
+            }
+        }
+
+        private async Task RefreshQueryStoreComparisonAsync(DateTime currentStart, DateTime currentEnd)
+        {
+            if (_comparisonRange == null)
+            {
+                SetQueryStoreComparisonMode(false);
+                return;
+            }
+
+            SetQueryStoreComparisonMode(true, _comparisonRange);
+
+            var items = await _databaseService!.GetQueryStoreComparisonAsync(
+                currentStart, currentEnd,
+                _comparisonRange.Value.From, _comparisonRange.Value.To);
+
+            var sorted = items
+                .OrderBy(x => x.SortGroup)
+                .ThenByDescending(x => x.SortableDurationDelta)
+                .ToList();
+
+            QueryStoreComparisonGrid.ItemsSource = sorted;
+        }
+
         public void SetTimeRange(int hoursBack, DateTime? fromDate = null, DateTime? toDate = null)
         {
             _isDrillDownActive = false;

Dashboard/Controls/ResourceMetricsContent.xaml

@@ -29,18 +29,6 @@
         <!-- Server Trends Sub-Tab — Correlated Timeline Lanes -->
         <TabItem Header="Server Trends">
             <DockPanel>
-                <StackPanel DockPanel.Dock="Top" Orientation="Horizontal" Margin="8,4,8,0">
-                    <TextBlock Text="Compare:" VerticalAlignment="Center" Margin="0,0,4,0"
-                               Foreground="{DynamicResource ForegroundBrush}"/>
-                    <ComboBox x:Name="CompareToCombo" SelectedIndex="0" Width="150"
-                              SelectionChanged="CompareToCombo_SelectionChanged"
-                              ToolTip="Overlay a reference period on the timeline charts">
-                        <ComboBoxItem Content="None"/>
-                        <ComboBoxItem Content="Yesterday"/>
-                        <ComboBoxItem Content="Last week"/>
-                        <ComboBoxItem Content="Same day last week"/>
-                    </ComboBox>
-                </StackPanel>
                 <local:CorrelatedTimelineLanesControl x:Name="CorrelatedLanes"/>
             </DockPanel>
         </TabItem>

Dashboard/Controls/ResourceMetricsContent.xaml.cs

@@ -1025,33 +1025,15 @@ private async Task LoadFileIoThroughputChartsAsync()
 
         #region Server Trends Tab
 
-        private async void CompareToCombo_SelectionChanged(object sender, SelectionChangedEventArgs e)
-        {
-            if (!IsLoaded) return;
-            ComparisonRange = GetComparisonRange();
-            await RefreshServerTrendsAsync();
-        }
-
         private (DateTime From, DateTime To)? ComparisonRange { get; set; }
 
         /// <summary>
-        /// Computes the reference time range for the comparison overlay.
-        /// Returns null if "None" is selected.
+        /// Sets the comparison range from the global Compare dropdown and refreshes Server Trends.
         /// </summary>
-        private (DateTime From, DateTime To)? GetComparisonRange()
+        public async Task SetComparisonRangeAsync((DateTime From, DateTime To)? range)
         {
-            if (CompareToCombo == null || CompareToCombo.SelectedIndex <= 0) return null;
-
-            var currentEnd = _serverTrendsToDate ?? DateTime.UtcNow;
-            var currentStart = _serverTrendsFromDate ?? currentEnd.AddHours(-_serverTrendsHoursBack);
-
-            return CompareToCombo.SelectedIndex switch
-            {
-                1 => (currentStart.AddDays(-1), currentEnd.AddDays(-1)),   // Yesterday
-                2 => (currentStart.AddDays(-7), currentEnd.AddDays(-7)),   // Last week
-                3 => (currentStart.AddDays(-7), currentEnd.AddDays(-7)),   // Same day last week
-                _ => null
-            };
+            ComparisonRange = range;
+            await RefreshServerTrendsAsync();
         }
 
         private async Task RefreshServerTrendsAsync()

Dashboard/Models/ComparisonItemBase.cs

@@ -0,0 +1,80 @@
+using System.Windows.Media;
+
+namespace PerformanceMonitorDashboard.Models
+{
+    public abstract class ComparisonItemBase
+    {
+        public string DatabaseName { get; set; } = "";
+
+        // Current period
+        public long ExecutionCount { get; set; }
+        public double AvgDurationMs { get; set; }
+        public double AvgCpuMs { get; set; }
+        public double AvgReads { get; set; }
+
+        // Baseline period
+        public long BaselineExecutionCount { get; set; }
+        public double BaselineAvgDurationMs { get; set; }
+        public double BaselineAvgCpuMs { get; set; }
+        public double BaselineAvgReads { get; set; }
+
+        // Flags
+        public bool IsNew => ExecutionCount > 0 && BaselineExecutionCount == 0;
+        public bool IsGone => ExecutionCount == 0 && BaselineExecutionCount > 0;
+
+        // Delta percentages (null when baseline is zero or item is new/gone)
+        public double? DurationDeltaPct => ComputeDelta(AvgDurationMs, BaselineAvgDurationMs);
+        public double? CpuDeltaPct => ComputeDelta(AvgCpuMs, BaselineAvgCpuMs);
+        public double? ReadsDeltaPct => ComputeDelta(AvgReads, BaselineAvgReads);
+        public double? ExecutionDeltaPct => ComputeDelta(ExecutionCount, BaselineExecutionCount);
+
+        // Display helpers for grid binding
+        public string DurationDeltaDisplay => FormatDelta(DurationDeltaPct);
+        public string CpuDeltaDisplay => FormatDelta(CpuDeltaPct);
+        public string ReadsDeltaDisplay => FormatDelta(ReadsDeltaPct);
+        public string ExecutionDeltaDisplay => FormatDelta(ExecutionDeltaPct);
+
+        public string StatusBadge => IsNew ? "NEW" : IsGone ? "GONE" : "";
+
+        // Sort key: NEW at top (0), normal by delta (1), GONE at bottom (2)
+        public int SortGroup => IsNew ? 0 : IsGone ? 2 : 1;
+        public double SortableDurationDelta => DurationDeltaPct ?? (IsNew ? double.MaxValue : double.MinValue);
+
+        // Color brushes for delta columns (red = regression, green = improvement)
+        public Brush DurationDeltaBrush => GetDeltaBrush(DurationDeltaPct, 25);
+        public Brush CpuDeltaBrush => GetDeltaBrush(CpuDeltaPct, 25);
+        public Brush ReadsDeltaBrush => GetDeltaBrush(ReadsDeltaPct, 50, 25);
+        public Brush ExecutionDeltaBrush => GetDeltaBrush(ExecutionDeltaPct, 100, 50);
+
+        private static readonly Brush RedBrush = new SolidColorBrush(Color.FromRgb(0xFF, 0x6B, 0x6B));
+        private static readonly Brush GreenBrush = new SolidColorBrush(Color.FromRgb(0x4E, 0xC9, 0xB0));
+        private static readonly Brush NeutralBrush = Brushes.Transparent;
+
+        static ComparisonItemBase()
+        {
+            RedBrush.Freeze();
+            GreenBrush.Freeze();
+        }
+
+        private static Brush GetDeltaBrush(double? delta, double redThreshold, double greenThreshold = 25)
+        {
+            if (!delta.HasValue) return NeutralBrush;
+            if (delta.Value > redThreshold) return RedBrush;
+            if (delta.Value < -greenThreshold) return GreenBrush;
+            return NeutralBrush;
+        }
+
+        private static double? ComputeDelta(double current, double baseline)
+        {
+            if (baseline == 0) return null;
+            return (current - baseline) / baseline * 100.0;
+        }
+
+        private static string FormatDelta(double? delta)
+        {
+            if (!delta.HasValue) return "\u2014";
+            var sign = delta.Value >= 0 ? "+" : "";
+            return $"{sign}{delta.Value:N1}%";
+        }
+    }
+}

Dashboard/Models/ProcedureStatsComparisonItem.cs

@@ -0,0 +1,9 @@
+namespace PerformanceMonitorDashboard.Models
+{
+    public class ProcedureStatsComparisonItem : ComparisonItemBase
+    {
+        public string SchemaName { get; set; } = "";
+        public string ObjectName { get; set; } = "";
+        public string FullName => string.IsNullOrEmpty(SchemaName) ? ObjectName : $"{SchemaName}.{ObjectName}";
+    }
+}

Dashboard/Models/QueryStatsComparisonItem.cs

@@ -0,0 +1,11 @@
+namespace PerformanceMonitorDashboard.Models
+{
+    public class QueryStatsComparisonItem : ComparisonItemBase
+    {
+        public string QueryHash { get; set; } = "";
+        public string? ObjectName { get; set; }
+        public string? SchemaName { get; set; }
+        public string? ObjectType { get; set; }
+        public string QueryText { get; set; } = "";
+    }
+}

Dashboard/ServerTab.xaml

@@ -105,6 +105,16 @@
                         <ToggleButton x:Name="AutoRefreshToggle" Content="Auto-Refresh: Off" Click="AutoRefreshToggle_Click" Margin="8,0,2,0" Padding="12,5" MinWidth="130" ToolTip="Toggle auto-refresh on/off. Configure interval in Settings."/>
                         <Button Content="Edit Schedules" Click="EditSchedules_Click" Margin="8,0,2,0" Padding="12,5" Style="{DynamicResource AccentButton}" ToolTip="Edit collector schedules (frequency, retention, enabled/disabled)"/>
                         <TextBlock Text="|" VerticalAlignment="Center" Margin="8,0,4,0" Foreground="{DynamicResource ForegroundBrush}"/>
+                        <TextBlock Text="Compare:" VerticalAlignment="Center" Margin="0,0,4,0" Foreground="{DynamicResource ForegroundBrush}"/>
+                        <ComboBox x:Name="CompareToCombo" SelectedIndex="0" Width="130" Margin="0,0,8,0"
+                                  SelectionChanged="CompareToCombo_SelectionChanged"
+                                  ToolTip="Compare current period against a baseline">
+                            <ComboBoxItem Content="None"/>
+                            <ComboBoxItem Content="Yesterday"/>
+                            <ComboBoxItem Content="Last week"/>
+                            <ComboBoxItem Content="Same day last week"/>
+                        </ComboBox>
+                        <TextBlock Text="|" VerticalAlignment="Center" Margin="0,0,4,0" Foreground="{DynamicResource ForegroundBrush}"/>
                         <TextBlock Text="Times:" VerticalAlignment="Center" Margin="0,0,4,0" Foreground="{DynamicResource ForegroundBrush}"/>
                         <ComboBox x:Name="TimeDisplayModeBox" Width="120" SelectionChanged="TimeDisplayMode_SelectionChanged" ToolTip="How timestamps are displayed across all tabs">
                             <ComboBoxItem Content="Server Time" Tag="ServerTime"/>