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We have a `user` GraphQL type. It has 200+ fields and resolvers into other data. Fortunately, clients don't need to pull everything. Well, within one of our fr

by 013a 6y ago

We have a `user` GraphQL type. It has 200+ fields and resolvers into other data. Fortunately, clients don't need to pull everything. Well, within one of our frontend apps, someone wrote a "GetUser" query fragment, wrapped it in a react hook to make it easy to use, and now anytime anyone anywhere wants to get a user, even with one field, they're getting 100+ fields they don't want. Anytime someone needs a new field on a user, they don't create a new query; they just add the field to that "GetUser" query. Now, I've told several GraphQL advocates that setup (in our local community and online), and unfailingly they balk at it. Well, you're doing GraphQL wrong, everyone makes mistakes, you should be more selective, etc etc etc. I think that's fair; being more specific sounds like a good pattern. Except, we are not certain the performance wouldn't suffer should we move everything to more selective queries. The issue is caching. If you have ten queries each requesting one field, the cache can't saturate until after ten network requests. But, one mega query, and now the remaining nine queries can just pull from the cache. Sure, the mega query takes longer than one mini-query, but its not longer than ten mini-queries. I only outline this to say: GraphQL is not a magic bullet. Every single thing you can do which would ruin a REST API is also possible in GraphQL. REST API responses naturally evolve into god objects. GraphQL APIs solve the god object issue server-side by saying "god objects are fine", then push the responsibility of not abusing it onto the client (and it should be obvious, the client is the worst place to solve almost every problem, but that's another topic). GraphQL is easier and better for some things, far harder for other things. At the end of the day, its no worse than REST. I don't recommend it, but that's only just because its new; unless a new technology offers some very easy to express, tactile benefits for your business, just wait for it to mature. When you get down to it, GraphQL's benefits are definitely not tactile, but they're still there, and I think over time it will evolve into something very interesting.

filoleg 6y ago
I agree with your point about caching, except, i think, it is missing one important detail that makes your argument less one-sided against GraphQL. What you described is absolutely correct, except it is only the case if we cache by query. If we cache by objects and fields, none of those issues you described become relevant, and caching by object/field (as opposed to caching by query) in general seems like a better practice imo, aside from certain very specific scenarios. In fact, it seems like the official GraphQL docs recommend that approach as well [0]. 0. https://graphql.org/learn/caching/ https://graphql.org/learn/caching/
- jtsiskin 6y ago
  Yes, caching is a pro FOR GraphQl, not against it.
- 013a 6y ago
  No, its still an issue. If you have QueryA which requests User { firstName } and QueryB which requests User { lastName }, those queries both have to request their data in order for both fields to be cached. If, instead, you have QueryC which does User { firstName, lastName }, but two usages of it (QueryC1/QueryC2), after QueryC1 requests, QueryC2 can use the cached results. This works whether you're doing Query/Operation level caching or Field/ID level caching. The former example works in neither. And QueryC is trivially faster than QueryA+QueryB because of network overhead. This isn't necessarily an issue with GraphQL (and, I thought I was clear about this, but: I'm not against GraphQL). Its a behavior of both typical REST implementations and GraphQL. And, to be clear, GraphQL's out-of-box caching story is more powerful than any REST implementation I've seen short of hyper-engineered FAANG companies, because it enables really powerful field/ID level caching across multiple queries. But it doesn't work in this case. The point is that its still very immature. Even the thought leaders (Apollo being the biggest one and worst offender) write these blog posts filled with Best Practices and Recommendations that often convey horrible advice and flat-out misrepresent GraphQL's actual advantages compared to REST. GraphQL solves a lot of REST's problems; it does NOT solve REST's "god-object" class of problems, like the grandparent comment suggests; and it introduces many new classes of problems that remain unsolved in the ecosystem because of how immature it is (one great example is OSI L7 inspection in many tertiary tools a typical SaaS app has. Many products like Datadog, CloudFront, AWS ALB, etc are capable of doing some really cool and powerful stuff out-of-the-box just by inspecting standard HTTP headers. REST is basically just standard HTTP; your resource is in the path, query parameters, http headers, its very standard. GraphQL is not, so many of these tools don't work out-of-box with GraphQL. People are catching up, but again, its immature).
  - filoleg 6y ago
    Thanks for clarifying, I genuinely appreciate comments like this one that go into actual details, without vague fluff or generalized claims. At this point, I am fully with you on this one.

by 013a 6y ago

filoleg 6y ago

I agree with your point about caching, except, i think, it is missing one important detail that makes your argument less one-sided against GraphQL. What you described is absolutely correct, except it is only the case if we cache by query. If we cache by objects and fields, none of those issues you described become relevant, and caching by object/field (as opposed to caching by query) in general seems like a better practice imo, aside from certain very specific scenarios. In fact, it seems like the official GraphQL docs recommend that approach as well [0]. 0. https://graphql.org/learn/caching/ https://graphql.org/learn/caching/

jtsiskin 6y ago
Yes, caching is a pro FOR GraphQl, not against it.
013a 6y ago
No, its still an issue. If you have QueryA which requests User { firstName } and QueryB which requests User { lastName }, those queries both have to request their data in order for both fields to be cached. If, instead, you have QueryC which does User { firstName, lastName }, but two usages of it (QueryC1/QueryC2), after QueryC1 requests, QueryC2 can use the cached results. This works whether you're doing Query/Operation level caching or Field/ID level caching. The former example works in neither. And QueryC is trivially faster than QueryA+QueryB because of network overhead. This isn't necessarily an issue with GraphQL (and, I thought I was clear about this, but: I'm not against GraphQL). Its a behavior of both typical REST implementations and GraphQL. And, to be clear, GraphQL's out-of-box caching story is more powerful than any REST implementation I've seen short of hyper-engineered FAANG companies, because it enables really powerful field/ID level caching across multiple queries. But it doesn't work in this case. The point is that its still very immature. Even the thought leaders (Apollo being the biggest one and worst offender) write these blog posts filled with Best Practices and Recommendations that often convey horrible advice and flat-out misrepresent GraphQL's actual advantages compared to REST. GraphQL solves a lot of REST's problems; it does NOT solve REST's "god-object" class of problems, like the grandparent comment suggests; and it introduces many new classes of problems that remain unsolved in the ecosystem because of how immature it is (one great example is OSI L7 inspection in many tertiary tools a typical SaaS app has. Many products like Datadog, CloudFront, AWS ALB, etc are capable of doing some really cool and powerful stuff out-of-the-box just by inspecting standard HTTP headers. REST is basically just standard HTTP; your resource is in the path, query parameters, http headers, its very standard. GraphQL is not, so many of these tools don't work out-of-box with GraphQL. People are catching up, but again, its immature).
- filoleg 6y ago
  Thanks for clarifying, I genuinely appreciate comments like this one that go into actual details, without vague fluff or generalized claims. At this point, I am fully with you on this one.