DbEye 1.1.0

DbEye

DbEye is a lightweight middleware for ASP.NET Core that detects N+1 query problems and slow queries in Entity Framework Core applications — right in your development logs.

⚠️ DbEye is intended for development use only. It automatically disables itself outside of the Development environment.

Installation

dotnet add package DbEye

Setup

Add DbEye to your Program.cs:

builder.Services.AddDbEye();
builder.Services.AddDbContext<AppDbContext>((serviceProvider, options) =>
{
    options.AddInterceptors(serviceProvider.GetRequiredService<DbEyeInterceptor>());
});

app.UseDbEye();

Configuration

By default, queries taking longer than 500ms are flagged as slow. You can customize this threshold globally or per endpoint:

builder.Services.AddDbEye(options =>
{
    options.SlowQueryThresholdMs = 500;
    options.EndpointThresholds = new Dictionary<string, int>
    {
        { "/api/reports", 2000 },
        { "/api/comments", 200 }
    };
});

Endpoints not listed in EndpointThresholds fall back to SlowQueryThresholdMs.

How it works

DbEye hooks into EF Core via an interceptor and analyzes query patterns on each request. When a problem is detected, a warning is emitted through ASP.NET Core's standard logging pipeline — it shows up directly in your terminal or VS Code output panel. When everything looks healthy, it logs a confirmation instead.

• N+1 detection — identifies when multiple queries are fired in a loop that could be resolved with a single join or Include()
• Slow query detection — flags queries that exceed the configured threshold
• Environment-aware — automatically skips all logic outside of Development, zero overhead in production

No external dashboard, no extra dependencies to run — just clear warnings where you already look.

Example output

N+1 detected:

warn: DbEye[0]
      --------------------------------------------------
      ⚠️  N+1 detected at GET /api/posts
      Query repeated 5x - SELECT * FROM "Comments" WHERE "PostId" = ...
      --------------------------------------------------

Slow query detected:

warn: DbEye[0]
      --------------------------------------------------
      ⚠️  Slow query detected at GET /api/comments
      Duration: 732ms - SELECT * FROM "Comments"
      --------------------------------------------------

No issues:

info: DbEye[0]
      --------------------------------------------------
      ✅  GET /api/posts - no issues detected
      --------------------------------------------------

Try it out

The repository includes a demo project with a pre-configured Postgres database. Just clone and run:

git clone https://github.com/BrunoSync/DbEye
cd DbEye
docker compose up --build

The API will be available at http://localhost:5000. Watch the warnings in real time:

docker compose logs -f api

Triggering N+1

GET /api/posts without the include parameter fires one query per post to load comments:

curl http://localhost:5000/api/posts

To fix it, pass ?include=true — DbEye will stay silent:

curl http://localhost:5000/api/posts?include=true

Triggering a slow query

GET /api/comments with ?delay=true simulates a slow query:

curl http://localhost:5000/api/comments?delay=true

Other endpoints

Supported frameworks

Support

If DbEye saved you from a N+1 in production, consider buying me a coffee ☕

License

MIT