Improve Health Monitoring service-detail query performance

HealthMonitoring/HealthMonitoring.Tests/Reporting/ObservationMetricsTests.cs

@@ -0,0 +1,24 @@
+using HealthMonitoring.Domain;
+using HealthMonitoring.Reporting;
+
+namespace HealthMonitoring.Tests.Reporting;
+
+public sealed class ObservationMetricsTests
+{
+    [Fact]
+    public void Uptime_percent_uses_all_observations_not_the_display_window()
+    {
+        var metrics = new ObservationMetrics(250, 225);
+
+        Assert.Equal(250, metrics.TotalCount);
+        Assert.Equal(90d, metrics.UptimePercent);
+    }
+
+    [Fact]
+    public void Uptime_percent_is_zero_when_no_observations_exist()
+    {
+        var metrics = new ObservationMetrics(0, 0);
+
+        Assert.Equal(0d, metrics.UptimePercent);
+    }
+}

HealthMonitoring/HealthMonitoring.Tests/Reporting/ServiceDetailLoadStateTests.cs

@@ -0,0 +1,36 @@
+using HealthMonitoring.Reporting;
+
+namespace HealthMonitoring.Tests.Reporting;
+
+public sealed class ServiceDetailLoadStateTests
+{
+    [Fact]
+    public void Loading_state_is_not_reported_as_not_found()
+    {
+        var state = ServiceDetailLoadState.Loading;
+
+        Assert.True(state.IsLoading);
+        Assert.False(state.IsNotFound);
+        Assert.Null(state.ErrorMessage);
+    }
+
+    [Fact]
+    public void Missing_state_is_reported_as_not_found()
+    {
+        var state = ServiceDetailLoadState.NotFound;
+
+        Assert.False(state.IsLoading);
+        Assert.True(state.IsNotFound);
+        Assert.Null(state.ErrorMessage);
+    }
+
+    [Fact]
+    public void Failed_state_exposes_error_without_being_reported_as_not_found()
+    {
+        var state = ServiceDetailLoadState.Failed("Database query failed.");
+
+        Assert.False(state.IsLoading);
+        Assert.False(state.IsNotFound);
+        Assert.Equal("Database query failed.", state.ErrorMessage);
+    }
+}

HealthMonitoring/HealthMonitoring/Components/Pages/ServiceDetail.razor

@@ -1,16 +1,25 @@
 @page "/services/{ServiceId}"
 @inject IDashboardQueryService Dashboard
+@inject ILogger<ServiceDetail> Logger
 
-<PageTitle>@(_model?.Service.Name ?? "Service") · Operational Support</PageTitle>
-@if (_model is null)
+<PageTitle>@(_loadState.Model?.Service.Name ?? "Service") · Operational Support</PageTitle>
+@if (_loadState.IsLoading)
+{
+    <p class="panel">Loading service details…</p>
+}
+else if (_loadState.ErrorMessage is not null)
+{
+    <p class="panel">Unable to load service details. Please try again later.</p>
+}
+else if (_loadState.IsNotFound)
 {
     <p class="panel">Service not found.</p>
 }
 else
 {
-<div class="page-heading"><div><p class="eyebrow">SERVICE DETAIL · @_model.Service.Environment</p><h1>@_model.Service.Name</h1><p class="muted">@MonitorDescription</p><p class="service-version-detail">Version: <strong>@(string.IsNullOrWhiteSpace(_model.Service.Version) ? "not reported" : _model.Service.Version)</strong></p></div><div><a class="button secondary" href="@($"/services/{ServiceId}/dependencies")">Manage dependency links</a> <a class="button secondary" href="/">Back to overview</a></div></div>
+<div class="page-heading"><div><p class="eyebrow">SERVICE DETAIL · @_model!.Service.Environment</p><h1>@_model.Service.Name</h1><p class="muted">@MonitorDescription</p><p class="service-version-detail">Version: <strong>@(string.IsNullOrWhiteSpace(_model.Service.Version) ? "not reported" : _model.Service.Version)</strong></p></div><div><a class="button secondary" href="@($"/services/{ServiceId}/dependencies")">Manage dependency links</a> <a class="button secondary" href="/">Back to overview</a></div></div>
     <div class="detail-status"><StatusBadge Status="@_model.Summary.Status" /> <span>Last checked @( _model.Summary.LastChecked?.ToLocalTime().ToString("dd MMM, HH:mm:ss") ?? "never")</span></div>
-    <div class="stat-grid three"><StatCard Label="Uptime (24 hours)" Value="@UptimeText" Class="healthy" /><StatCard Label="Observations" Value="@_model.Observations.Count" Class="neutral" /><StatCard Label="Response" Value="@ResponseText" Class="neutral" /></div>
+    <div class="stat-grid three"><StatCard Label="Uptime (24 hours)" Value="@UptimeText" Class="healthy" /><StatCard Label="Observations" Value="@_model.ObservationCount" Class="neutral" /><StatCard Label="Response" Value="@ResponseText" Class="neutral" /></div>
     <section class="panel"><h2>Status timeline</h2><div class="timeline">@foreach (var observation in TimelineObservationSelector.Select(_model.Observations)) { <span class="timeline-segment @observation.Status.ToString().ToLowerInvariant()" title="@observation.ObservedAtUtc.ToLocalTime()"></span> }</div></section>
     <section class="panel"><h2>Dependency details</h2>@if (_model.Checks.Count == 0) { <p class="muted">No dependency details have been returned.</p> } else { <div class="check-table"><div class="table-heading"><span>Check</span><span>Status</span><span>Duration</span><span>Details</span></div>@foreach (var check in LatestChecks) { var link = _model.DependencyLinks.FirstOrDefault(item => string.Equals(item.DependencyName.Trim(), check.Result.Name.Trim(), StringComparison.OrdinalIgnoreCase)); <div class="service-row"><div>@if (link is null) { <strong>@check.Result.Name</strong> } else { <a class="dependency-link" href="@($"/services/{link.TargetServiceId}")"><strong>@check.Result.Name</strong> ↗</a> }</div><div><StatusBadge Status="@check.Result.Status" /></div><div>@check.Result.Duration.TotalMilliseconds.ToString("0") ms</div><div>@(check.Result.Description ?? check.Result.Exception ?? "No detail")</div></div>}</div> }</section>
     <details class="panel raw"><summary>Latest raw health response</summary><pre>@(_model.Observations.FirstOrDefault()?.RawResponseJson ?? "No response recorded.")</pre></details>
@@ -19,6 +28,7 @@ else
 @code {
     [Parameter] public string ServiceId { get; set; } = string.Empty;
     private ServiceDetailModel? _model;
+    private ServiceDetailLoadState _loadState = ServiceDetailLoadState.Loading;
     private IEnumerable<ObservedCheck> LatestChecks => _model?.Observations
         .SelectMany(observation => observation.Checks.Select(check => new ObservedCheck(check, observation.ObservedAtUtc)))
         .GroupBy(item => item.Result.Name, StringComparer.OrdinalIgnoreCase)
@@ -32,7 +42,24 @@ else
         MonitorType.SqlServer => "SQL Server monitor",
         _ => _model?.Service.HealthUrl?.ToString() ?? "HTTP health monitor"
     } ?? "Service monitor";
-    protected override async Task OnParametersSetAsync() => _model = await Dashboard.GetServiceDetailAsync(ServiceId, TimeSpan.FromHours(24), CancellationToken.None);
+    protected override async Task OnParametersSetAsync()
+    {
+        _loadState = ServiceDetailLoadState.Loading;
+        _model = null;
+
+        try
+        {
+            _model = await Dashboard.GetServiceDetailAsync(ServiceId, TimeSpan.FromHours(24), CancellationToken.None);
+            _loadState = _model is null
+                ? ServiceDetailLoadState.NotFound
+                : ServiceDetailLoadState.Loaded(_model);
+        }
+        catch (Exception exception)
+        {
+            Logger.LogError(exception, "Unable to load service detail for {ServiceId}.", ServiceId);
+            _loadState = ServiceDetailLoadState.Failed("Service details could not be loaded.");
+        }
+    }
 
     private sealed record ObservedCheck(HealthCheckResult Result, DateTimeOffset ObservedAtUtc);
 }

HealthMonitoring/HealthMonitoring/Reporting/DashboardModels.cs

@@ -5,4 +5,4 @@ namespace HealthMonitoring.Reporting;
 public sealed record DashboardOverview(IReadOnlyList<ServiceDashboardRow> Services, int Healthy, int Degraded, int Unhealthy, int OpenIncidents);
 public sealed record ServiceDashboardRow(string ServiceId, string Name, string Environment, string? Version, HealthStatus Status, TimeSpan? ResponseDuration, double UptimePercent, DateTimeOffset? LastChecked, string? LastError);
 public sealed record ResolvedDependencyLink(string DependencyName, string TargetServiceId, string TargetServiceName);
-public sealed record ServiceDetailModel(MonitoredService Service, ServiceDashboardRow Summary, IReadOnlyList<HealthObservation> Observations, IReadOnlyList<ServiceIncident> Incidents, IReadOnlyList<HealthCheckResult> Checks, IReadOnlyList<ResolvedDependencyLink> DependencyLinks);
+public sealed record ServiceDetailModel(MonitoredService Service, ServiceDashboardRow Summary, int ObservationCount, IReadOnlyList<HealthObservation> Observations, IReadOnlyList<ServiceIncident> Incidents, IReadOnlyList<HealthCheckResult> Checks, IReadOnlyList<ResolvedDependencyLink> DependencyLinks);

HealthMonitoring/HealthMonitoring/Reporting/DashboardQueryService.cs

@@ -35,15 +35,21 @@ public async Task<DashboardOverview> GetOverviewAsync(TimeSpan range, Cancellati
         var service = await dbContext.MonitoredServices.AsNoTracking().SingleOrDefaultAsync(item => item.ServiceId == serviceId && item.ArchivedAtUtc == null, cancellationToken);
         if (service is null) return null;
         var from = DateTimeOffset.UtcNow.Subtract(range);
-        var observations = await dbContext.HealthObservations.AsNoTracking().Include(item => item.Checks).Where(item => item.MonitoredServiceId == service.Id && item.ObservedAtUtc >= from).OrderByDescending(item => item.ObservedAtUtc).ToListAsync(cancellationToken);
+        var observationQuery = dbContext.HealthObservations.AsNoTracking().Where(item => item.MonitoredServiceId == service.Id && item.ObservedAtUtc >= from);
+        var observationMetrics = await observationQuery
+            .GroupBy(_ => 1)
+            .Select(group => new ObservationMetrics(group.Count(), group.Count(item => item.Status == HealthStatus.Healthy)))
+            .SingleOrDefaultAsync(cancellationToken) ?? new ObservationMetrics(0, 0);
+        var observations = await observationQuery.AsSplitQuery().Include(item => item.Checks).OrderByDescending(item => item.ObservedAtUtc).Take(TimelineObservationSelector.MaximumSegments).ToListAsync(cancellationToken);
         var incidents = await dbContext.ServiceIncidents.AsNoTracking().Where(item => item.MonitoredServiceId == service.Id && (item.EndedAtUtc == null || item.EndedAtUtc >= from)).OrderByDescending(item => item.StartedAtUtc).ToListAsync(cancellationToken);
         var snapshot = await dbContext.ServiceStatusSnapshots.AsNoTracking().SingleOrDefaultAsync(item => item.MonitoredServiceId == service.Id, cancellationToken);
         var checks = observations.SelectMany(item => item.Checks).ToArray();
         var dependencyLinks = await dbContext.ServiceDependencyLinks.AsNoTracking()
             .Where(link => link.MonitoredServiceId == service.Id)
             .Join(dbContext.MonitoredServices.AsNoTracking(), link => link.TargetMonitoredServiceId, target => target.Id, (link, target) => new ResolvedDependencyLink(link.DependencyName, target.ServiceId, target.Name))
             .ToListAsync(cancellationToken);
-        return new ServiceDetailModel(service, ToRow(service, snapshot, observations), observations, incidents, checks, dependencyLinks);
+        var summary = ToRow(service, snapshot, observations) with { UptimePercent = observationMetrics.UptimePercent };
+        return new ServiceDetailModel(service, summary, observationMetrics.TotalCount, observations, incidents, checks, dependencyLinks);
     }
 
     private static ServiceDashboardRow ToRow(MonitoredService service, ServiceStatusSnapshot? snapshot, IReadOnlyList<HealthObservation> observations)

HealthMonitoring/HealthMonitoring/Reporting/ObservationMetrics.cs

@@ -0,0 +1,6 @@
+namespace HealthMonitoring.Reporting;
+
+public sealed record ObservationMetrics(int TotalCount, int HealthyCount)
+{
+    public double UptimePercent => TotalCount == 0 ? 0 : HealthyCount * 100d / TotalCount;
+}

HealthMonitoring/HealthMonitoring/Reporting/ServiceDetailLoadState.cs

@@ -0,0 +1,13 @@
+namespace HealthMonitoring.Reporting;
+
+public sealed record ServiceDetailLoadState(bool IsLoading, ServiceDetailModel? Model, string? ErrorMessage)
+{
+    public bool IsNotFound => !IsLoading && Model is null && ErrorMessage is null;
+
+    public static ServiceDetailLoadState Loading { get; } = new(true, null, null);
+    public static ServiceDetailLoadState NotFound { get; } = new(false, null, null);
+
+    public static ServiceDetailLoadState Loaded(ServiceDetailModel model) => new(false, model, null);
+
+    public static ServiceDetailLoadState Failed(string errorMessage) => new(false, null, errorMessage);
+}