Are `lean` queries supported?

[SnidelyWhiplash]

As I understand it, queries return fully instantiated Mongoose models by default. But you can override this if you just need the raw data, and don't plan on calling any instance methods, etc by using the lean option...

In my (limited) testing, it doesn't seem like that is supported in resolvers here..? I've tried both Model.find({ query }, null, { lean: true }) and Model.find({ query }).lean() but it seems to prevent me from querying relational data. (It's been a while since I tested, I'm only just now circling back to this. I can provide fuller examples/errors if needed).

In the past, on REST projects, I've noticed significant performance impacts when querying for multiple documents without lean, and in my current GraphQL project I'm thinking this may also be the reason for slow query times.

Thanks for any insight!

[SnidelyWhiplash]

Is there any input on this please? cc @nodkz ?

[nodkz]

@SnidelyWhiplash sorry for late response. I was terribly busy with preparation for 2 conference talks and 2 active projects.

Let think what we can do with lean:

• Firstly it will be additional resolvers (cause lean breaks all virtual fields, hooks and custom logic from models)
• To move this feature, can you provide a test case 140-test.js via Pull Request in https://github.com/graphql-compose/graphql-compose-mongoose/tree/master/src/__tests__/guthub_issues folder? There are the bunch of other tests, which helps you to write a new one ;) We will resolve this feature inside your PR.

Thanks! Hope this problem is still actual for you.

[SnidelyWhiplash]

Hi @nodkz. This reply is incredibly delayed, sorry for that! We moved on to other issues, but now we're revisiting this.

I'll try to open a PR with a test, but I was curious if perhaps there has already been any movement on this feature? If my understanding is correct, using .lean(), especially when querying for multiple documents, is significantly faster than not (anywhere from 3 - 10 times faster).

Thanks!

references:
https://www.tothenew.com/blog/high-performance-find-query-using-lean-in-mongoose-2/
https://mongoosejs.com/docs/tutorials/lean.html

[jdbdnz]

@SnidelyWhiplash I found a workaround. Albeit not perfect as it isn't a query option but instead specified during composition.

tc.getResolver('findMany').wrapResolve(next => resolveParams => next({
  ...resolveParams,
  beforeQuery: (query) => query.lean(),
}))

Check out this file for more context about how it works src/resolvers/helpers/beforeQueryHelper.js

@nodkz a perfect solution IMO would be to add lean as a resolver argument.

[nodkz]

New lean-resolvers were added in 9.0.0-alpha.3.

[nodkz]

*Lean resolvers were removed in favor of { lean: true } config option in basic resolvers.

More details here: #263 (comment)