Question: query same Entity in two different sources?

[Juan Cazala]

If I have two exact subgraphs deployed on different chains, is it possible to query a single entity that returns a list of results from both sources?

The two sources have the same schema for the Entity, but the records don't share a unique identifier.

For examle, I have an entity Token on both subgraphs:

type Token @entity {
  id: ID! #address
  name: String
}

And this query when executed on each subgraph:

query {
  tokens {
    id
    name
  }
}

Return the following on the Ethereum subgraph:

{
  "tokens": [
    {
      "id": "0x1",
      "name": "FOO"
    }
  ]
}

And this on the Polygon one:

{
  "tokens": [
    {
      "id": "0x2",
      "name": "BAR"
    }
  ]
}

And I want to be able to run that same query and get this result:

{
  "tokens": [
    {
      "id": "0x1",
      "name": "FOO"
    },
    {
      "id": "0x2",
      "name": "BAR"
    }
  ]
}

And be able to apply sorting/filtering on top of it. Is that possible with the current state of the graph-client?

[Juan Cazala]

I tried this already using some of our Ethereum/Polygon subgraphs but I'm only getting results from the first source and the other one is completely ignored. If I comment the first one then I start getting the results from the other. I don't know if I'm missing some configuration to tell the graph mesh to treat both entities as the same (even tho they are already called the same).

[Dotan Simha]

It sounds like the cross-chain feature (see https://github.com/graphprotocol/graph-client/tree/main/examples/cross-chain-sdk), but with different sources?
I mean, it is possible to merge responses easily with Graph Client, and it is possible to orchestrate calls to 2 different Subgraphs, so I think it might be possible with some adjustments.
@ardatan what do you think?

[Arda TANRIKULU]

You can overwrite tokens as an additional resolver;

export const resolvers: Resolvers = {
   Query: {
      async tokens(root, args, context, info) {
         const tokensNonFlat = await Promise.all([
           context.Ethereum.Query.tokens({ root, args, context, info }),
           context.Polygon.Query.tokens({ root, args, context, info })
         ]);
         return tokenNonFlat.flat();
      }
   }
}

[Juan Cazala]

You can overwrite tokens as an additional resolver;

export const resolvers: Resolvers = {
   Query: {
      async tokens(root, args, context, info) {
         const tokensNonFlat = await Promise.all([
           context.Ethereum.Query.tokens({ root, args, context, info }),
           context.Polygon.Query.tokens({ root, args, context, info })
         ]);
         return tokenNonFlat.flat();
      }
   }
}

Thanks for the resposne @dotansimha @ardatan. Would that work for sorting/pagintation tho? Or would the results be ordered as [...ethereum, ...polygon]? Sorting/filtering/pagination of the results is key for our use case.

For example, if I'm fetching NFTs in a marketplace and sorting the results by price, and the Ethereum ones are an order of magnitude more expensive than the Polygon ones, if the results are always [...ethereum, ...polygon] even if I orderBy: price (from cheaper to more expensive) I will always see the Ethereum results in the first page even tho the Polygon results should show up first.

[Arda TANRIKULU]

const [ethResults, polygonResults] = await Promise.all([
           context.Ethereum.Query.tokens({ root, args, context, info }),
           context.Polygon.Query.tokens({ root, args, context, info })
         ]);
         return [...ethResults, ...polygonResults];
      }

You can do this to change priority (it is just JavaScript, nothing with Graph Client).
I don't think Graph Client can handle the pagination in total results but send the same arguments to them.
@dotansimha

[Dotan Simha]

You can do this to change priority (it is just JavaScript, nothing with Graph Client). I don't think Graph Client can handle the pagination in total results but send the same arguments to them. @dotansimha

Yeah, I agree that this is a tricky one to handle with a magic config...