How to use batch loaders in SPQR

Hi! My question is connected with solving N+1 problem. I have a query: @GraphQLQuery public List<Contact> contactList(@GraphQLContext User user, @GraphQLArgument(name = "offset", defaultValue = "0") int offset, @GraphQLArgument(name = "limit", defaultValue = "50") int limit) { return ....<some database logic> } and it’s ok if i just want to retrieve one user, cause it costs me only 2 queries. But when I want to retrieve lets say 100 Users it becomes harder to compute. I found GraphQL DataLoader that potentially is able to solve the issue, but can’t make it work. I was tring to base my implementation on this but it didn’t work.

[slavap]

Just for reference if someone finds this issue by googling 😃 This solution works: https://github.com/graphql-java-kickstart/graphql-spring-boot/tree/master/example-request-scoped-dataloader

no need for CustomGraphQLContextBuilder, just enough the following (with graphql-spqr-spring-boot-starter):

    @Bean
    public DataLoaderRegistryFactory dataLoaderRegistryFactory() {
        return new DataLoaderRegistryFactory() {
            @Override
            public DataLoaderRegistry createDataLoaderRegistry() {
                return buildDataLoaderRegistry();
            }
        };
    }

In case no starter used, see https://github.com/graphql-java/graphql-java/issues/1254

The only thing you have to use:

@GraphQLEnvironment ResolutionEnvironment env
env.dataFetchingEnvironment

for getting fetching environment.

[kaqqao]

The latest graphql-java has a better organization. DataLoaderRegistry now goes into ExecutionInput and DataLoaderDispatcherInstrumentation is always registered. Also, DataFetchingEnvironment gives access to ``DataLoaderRegistry` directly.