Can't reach database server when doing a large findMany query

Bug description

When I try the following query, I get the following error:

const users = await p.user.findMany({
  include: { quiz: true },
})

(node:7642) UnhandledPromiseRejectionWarning: Error:
Invalid `prisma.user.findMany()` invocation:

 Can't reach database server at `localhost`:`5432`

Please make sure your database server is running at `localhost`:`5432`.

With some initial testing, I noticed removing the include argument allows the query to run just fine.

// works
const users = await p.user.findMany({}) 

Also, I could leave the include in if I limited the number of rows with take. Roughly 32,000 seemed to be the limit.

// works
const users = await p.user.findMany({
  include: { quiz: true },
  take: 32000,
})

// error
const users = await p.user.findMany({
  include: { quiz: true },
  take: 40000,
})

I think this is a bug. But if it’s a known limitation, it would be good if there was a better error message. I initially spent a long time troubleshooting my connection to postgres.

EDIT: I just tested this with the app running on heroku with a heroku managed database. I get the exact same error, so it’s not an issue with my local db.

How to reproduce

Run:

p.user.findMany({
  include: { quiz: true },
})

Both user and quiz have about 100k rows.

Prisma information

model User {
  id       String    @default(uuid())
  email    String    @id @unique
  customer Boolean   @default(false)
  name     String?
  acDate   DateTime?
  quiz     Quiz?
}

model Quiz {
  id         String    @id @default(uuid())
  firstName  String?
  skill      String
  playstyle  String
  discipline String
  age        String
  gender     String
  racketNum  Int?
  date       DateTime?
  user       User      @relation(fields: [userEmail], references: [email], onDelete: Cascade)
  userEmail  String
}

Environment & setup

• OS: Windows 10 running WSL2 Ubunutu 20.04
• Database: A local postgres instance
• Node.js version: v14.5.0

Prisma Version

prisma                  : 3.0.2
@prisma/client          : 3.0.2
Current platform        : debian-openssl-1.1.x
Query Engine (Node-API) : libquery-engine 2452cc6313d52b8b9a96999ac0e974d0aedf88db (at node_modules/@prisma/engines/libquery_engine-debian-openssl-1.1.x.so.node)
Migration Engine        : migration-engine-cli 2452cc6313d52b8b9a96999ac0e974d0aedf88db (at node_modules/@prisma/engines/migration-engine-debian-openssl-1.1.x)
Introspection Engine    : introspection-core 2452cc6313d52b8b9a96999ac0e974d0aedf88db (at node_modules/@prisma/engines/introspection-engine-debian-openssl-1.1.x)
Format Binary           : prisma-fmt 2452cc6313d52b8b9a96999ac0e974d0aedf88db (at node_modules/@prisma/engines/prisma-fmt-debian-openssl-1.1.x)
Default Engines Hash    : 2452cc6313d52b8b9a96999ac0e974d0aedf88db
Studio                  : 0.423.0

[nwidynski]

This is directly related to #8878

[jkomyno]

We have closed the original issue in prisma@4.4.0, please see this comment.