TypeORM query profiling

This tutorial shows how to add the TypeORM collector to profile SQL queries in a NestJS application that uses PostgreSQL via @nestjs/typeorm.

Prerequisites

• @eleven-labs/nest-profiler installed and configured
• @nestjs/typeorm and typeorm installed with a working DataSource

Step 1 — Install the package

pnpm add @eleven-labs/nest-profiler-typeorm

Step 2 — Register the collector

Add TypeOrmCollectorModule after TypeOrmModule in your root module:

import { TypeOrmModule } from '@nestjs/typeorm';
import { TypeOrmCollectorModule } from '@eleven-labs/nest-profiler-typeorm';

@Module({
  imports: [
    TypeOrmModule.forRootAsync({ ... }),
    ProfilerModule.forRoot({ isGlobal: true }),
    TypeOrmCollectorModule.forRoot({
      slowQueryThreshold: 100, // queries > 100ms are highlighted (default)
    }),
  ],
})
export class AppModule {}

No other configuration is needed — the collector injects the DataSource automatically via @InjectDataSource().

Step 3 — Instrument your services with spans

Use startSpan() to add meaningful labels to the Timeline panel alongside your TypeORM calls:

import { ProfilerService } from '@eleven-labs/nest-profiler';

@Injectable()
export class ProductsService {
  constructor(
    @InjectRepository(Product) private readonly repo: Repository<Product>,
    private readonly profiler: ProfilerService,
  ) {}

  async findAll(): Promise<Product[]> {
    const stop = this.profiler.startSpan('db.products.findAll');
    const result = await this.repo.find({ order: { createdAt: 'DESC' } });
    stop();
    return result;
  }
}

Step 4 — Test it

Start your application and make a request that triggers a database query:

curl -i http://localhost:3000/products

Copy the X-Debug-Token from the response headers, open /_profiler/{token}, and click the Database tab.

You will see:

• Each SQL query with its type badge (SELECT, INSERT, …)
• Duration per query with a bar chart indicator
• Slow queries highlighted in red
• Bound parameters

The Timeline panel shows the db.products.findAll span alongside other phases.

How it works

The collector patches dataSource.createQueryRunner() to wrap every QueryRunner.query() call with timing. The patch records entries directly into the CLS profile for the current request, then TypeOrmCollector.collect() reads and returns them.

This approach captures:

• All queries from TypeORM Repositories
• All queries from the EntityManager
• Raw queries via dataSource.query()

Queries executed outside a request context (e.g., during module initialization) are silently ignored since there is no active CLS profile.