/mikroorm-em-demo

Primary LanguageTypeScript

mikroorm-em-demo

This is a test repository for demonstrating memory leaks into the global EntityManager when using transactions.

Local development

For local development, it is necessary to execute the following commands:

npm install
docker-compose up -d --build
npm run orm migration:fresh -- --seed=InitialSeeder
npm run start:debug

How to reproduce the issue

  1. After launching NestJS in debug mode, it is necessary to open any Chromium engine-based browser, go to the link browser://inspect and open the required debugger;
  2. Next, you need to start memory recording while saving the timeline;
  3. Then, you need to go to the URL localhost:3000/update-entities?ids=1,2,3,4,5,6,7,8,9,10 (you can specify any entity identifiers, by default InitialSeeder creates 150 instances);
  4. After completing the update, end the recording, and you will be able to verify that the TestEntity is not cleared from memory.

Even with the presence of em.clear() on the 27th line in the file ./src/app.service.ts, TestEntity still remains in memory:

img.png

Why am I confident that it is preserved in the global context?

If you insert the clearing of the global context (this.#em.clear()) into the body of the updateEntities function before starting the transaction, then everything works correctly:

img_1.png