Why should you care?

ShopNest Black Friday needs alerts when SQL dependency duration spikes or __EFMigrationsHistory lags on a pod.

See it live — copy this example

Paste into a .NET project with EF Core packages, then run with LocalDB/SQL Server (dotnet ef / dotnet run).

// Application Insights automatic dependency tracking captures SQL
builder.Services.AddApplicationInsightsTelemetry();

// Custom metric on SaveChanges:
public override async Task<int> SaveChangesAsync(CancellationToken ct = default)
{
    var sw = Stopwatch.StartNew();
    var count = await base.SaveChangesAsync(ct);
    _telemetry.TrackMetric("ShopNest.SaveChanges.DurationMs", sw.ElapsedMilliseconds);
    _telemetry.TrackMetric("ShopNest.SaveChanges.AffectedRows", count);
    return count;
}

What happened?

• Application Insights traces SQL dependencies per request.
• Custom metrics on SaveChanges highlight slow commits.
• Compare migration history table across environments in release checklist.

Practice next

1. Enable APM SQL dependency collection on ShopNest API.
2. Alert when p95 SQL dependency exceeds threshold.
3. Dashboard connection count and deadlock DMVs on SQL Server.
4. Add health check: db.Database.GetPendingMigrationsAsync() empty.
5. Log TagWith query names into App Insights custom properties.

Remember

APM tracks EF SQL dependencies. Custom metrics on SaveChanges optional. Migration drift checks part of deploy.

ShopNest ops dashboard

Pager fires when ShopNest SQL dependency p95 > 500ms during sale — runbook checks blocking DMVs.

Outcome: Incident resolved in 12 minutes with telemetry pinpointing category query regression.