batch-size.md

graphql-provider/Configure batch size

Graphql-provider automatically applies DataLoaders for all associated fields, the user can't cancel this behavior (because not using DataLoader is harmful and not beneficial), so graphql-provider does not have performance problems caused by N+1 query.

The only operation the user is allowed to do is to configure the batchSize of the DataLoader

1. Field level configuration

@Component
class BookMapper: EntityMapper<Book, UUID>() {

    override fun EntityTypeDSL<Book, UUID>.config() {
    
        list(Book::authors) {
            db { ... }
            graphql {
                batchSize = 16 // Here it is
            }
        }
        
        ... other configuration ...
    }
}

For EntityMapper's reference, list, connection, mappedReference, mappedList, mappedConnection and userImplementation configurations, allows users to configure batchSize in a code block named graphql.

2. Entity level configuration

If the user does not configure field-level batchSize, grapqhl-provider will look for entity-level batchSize configuration.

@Component
class BookMapper: EntityMapper<Book, UUID>() {

    override fun EntityTypeDSL<Book, UUID>.config() {
    
        graphql {
            defaultBatchSize = 128 // α
            defaultCollectionBatchSize = 16 // β
        }
        
        ... other configuration ...
    }
}

• α: Provides default batchSize for all associated fields mapped by reference and mappedReference in the current entity type
• β: Provides default batchSize for all associated fields mapped by list, connection, mappedList and mappedConnection in the current entity type

3. Global level configuration

When there is no batchSize related configuration at both the field level and entity level, graphql-provider will use the global level configuration.

You can configure global defaults in spring-boot's application.yml:

graphql:
    provider:
        defaultBatchSize: 128
        defaultCollectionBatchSize: 16

If the user does not configure the global batchSize in application.yml (or application.properties), the defaultBatchSize is 128, and the defaultCollectionBatchSize is 16.

---

< Previous: Map entities | Home | Next: Add arguments to query >