Batching Arrays and Queries

What is Array Batching?

It's quite common for stitching to fetch supporting data for each record in an array. Given [1, 2, 5] as an array of record IDs, we could query a subschema for each of those records individually:

# product(id: Int!): Product

query { product(id: 1) { name } }
query { product(id: 2) { name } }
query { product(id: 5) { name } }

However, this is pretty inefficient (yes, this is absolutely an N+1 query). Each query must be delegated, resolved, and call the database individually. This would be significantly more efficient to resolve all of these records at once using an array service:

# products(ids: [Int!]!): [Product]!

query { products(ids: [1, 2, 5]) { name } }

That, in a nutshell, is array batching. Rather than performing single delegations on each of a list of records, we'd prefer to perform one delegation on behalf of the entire list that resolves everything at once.

What is Query Batching?

tktk