Query Engine keeps running even after the parent process is killed when using `migrate reset` or `db seed`

Bug description

The issue is in that the query engine processes keep the connection pool open even when the parent Node process crashes/is killed. This means massive memory and connection leaks in production if your application is known to crash and is restored automatically by some other entity. This usually results in too many open connections and your DB rejecting any additional connection requests and

On my MBP query-engine-darwin keeps running long after my NestJS app process is gone. It even happens after running some of the migrations related stuff, e.g. prisma migrate reset --preview-feature.

Caching the Prisma instance resolves this only for use cases described in #1983, e.g. hot reloading in Node apps such as NestJS.

How to reproduce

Run prisma migrate reset --preview-feature multiple times and check the running processes on your system. Make sure to have a seed file that establishes a connection to the database.

Expected behavior

All native processes should end after the parent Node process has quit.

Prisma information

Any schema connecting to the PostgreSQL DB in a container.

Environment & setup

• OS: macOS
• Database: PostgreSQL
• Node.js version: 14.16.1
• Prisma version: 2.22.1

prisma               : 2.22.1
@prisma/client       : 2.22.1
Current platform     : darwin
Query Engine         : query-engine 60cc71d884972ab4e897f0277c4b84383dddaf6c (at node_modules/@prisma/engines/query-engine-darwin)
Migration Engine     : migration-engine-cli 60cc71d884972ab4e897f0277c4b84383dddaf6c (at node_modules/@prisma/engines/migration-engine-darwin)
Introspection Engine : introspection-core 60cc71d884972ab4e897f0277c4b84383dddaf6c (at node_modules/@prisma/engines/introspection-engine-darwin)
Format Binary        : prisma-fmt 60cc71d884972ab4e897f0277c4b84383dddaf6c (at node_modules/@prisma/engines/prisma-fmt-darwin)
Default Engines Hash : 60cc71d884972ab4e897f0277c4b84383dddaf6c
Studio               : 0.379.0

[bencun]

@Jolg42 This doesn’t seem to be a seed issue only. Please, pay attention to the original comment: this is also relevant in any other use case, not just the seeding. In our case it was a NestJS app that had a proper $disconnect() call when an app is destroyed. That call did nothing on our end and, therefore, even after our app exits properly we still get a hanging query engine process. Mac only, on Windows there’s no such issue.

[bencun]

@janpio Yes, as described this also happens when I kill my app’s Node process with Ctrl+C (it’s a NestJS app) or even force quit it through the Activity Monitor. The Query Engine process keeps running.

Interestingly it doesn’t happen when I run prisma migrate dev but it does when running prisma migrate reset.

I’ll create a seed file that creates a reproducible case for the reset command very soon.