Batching JoinMonster calls

[TuurDutoit]

Describe the problem you'd like to have solved

We have some GraphQL queries where the top-level field is resolved from a different source, but nested objects are resolved using Join Monster. For example:

query {
  courses {
    id
    title
    pool {
      id
      title
      views {
        id
        question
      }
    }
  }
}

In this case, we have a resolver on Query.courses that fetches data from a different API. Course.pool and Pool.views are using Join Monster to query our database (pools and views tables, respectively).
With this query, we run into an n+1 issue: as Query.courses returns a list of courses, and Course.pool calls Join Monster for each course, we're making a DB query for each course!

Describe the ideal solution

A solution that would allow us to batch the Join Monster calls, something like a DataLoader, would be very helpful.

Alternatives and current work-arounds

We tried using batchDelegateToSchema from graphql-tools, but had some problems to get it to work reliably.

Additional context