Class ExecutionBenchmark

src/jmh/java/benchmark/ExecutionBenchmark.java:58–427

Measures the graphql-java engine's core execution overhead (field resolution, type checking, result building) with a balanced, realistic workload while minimising data-fetching work. Schema: 20 object types across 4 depth levels (5 types per level). Query shape: ~530 queried fields, ~2000 result

 * DataLoader (child fields resolved via batched DataLoader calls).
 */
@Warmup(iterations = 2, time = 5)
@Measurement(iterations = 3)
@Fork(2)
public class ExecutionBenchmark {

    // 4 levels of object types below Query → total query depth = 5
    private static final int LEVELS = 4;
    // 5 types per level = 20 types total
    private static final int TYPES_PER_LEVEL = 5;
    // Intermediate types: 5 scalar fields + child_a + child_b = 7 selections
    private static final int SCALAR_FIELDS = 5;
    // Leaf types: 7 scalar fields
    private static final int LEAF_SCALAR_FIELDS = 7;
    // Query: 5 top-level fields (2 single + 3 list)
    private static final int QUERY_FIELDS = 5;
    private static final int QUERY_SINGLE_COUNT = 2;
    // List fields return 2 items each
    private static final int LIST_SIZE = 2;

    // Schema types shared by both variants: types[0] = L4 (leaf), types[LEVELS-1] = L1
    private static final GraphQLObjectType[][] schemaTypes = buildSchemaTypes();
    private static final GraphQLObjectType queryType = buildQueryType();
    static final String query = mkQuery();
    private static final String queryId = "exec-benchmark-query";

    // ---- Baseline variant (PropertyDataFetcher with embedded Maps) ----
    static final GraphQL graphQL = buildGraphQL();

    // ---- DataLoader variant ----
    // levelStores[i] holds all DTOs at schema level i+1 (index 0 = L1, 3 = L4)
    @SuppressWarnings("unchecked")
    private static final Map<String, Map<String, Object>>[] levelStores = new Map[LEVELS];
    static {
        for (int i = 0; i < LEVELS; i++) {
            levelStores[i] = new HashMap<>();
        }
    }
    static final GraphQL graphQLWithDL = buildGraphQLWithDataLoader();
    private static final ExecutorService batchLoadExecutor = Executors.newCachedThreadPool();
    private static final BatchLoader<String, Map<String, Object>> batchLoaderL2 =
            keys -> CompletableFuture.supplyAsync(
                    () -> keys.stream().map(k -> levelStores[1].get(k)).collect(Collectors.toList()),
                    batchLoadExecutor);
    private static final BatchLoader<String, Map<String, Object>> batchLoaderL3 =
            keys -> CompletableFuture.supplyAsync(
                    () -> keys.stream().map(k -> levelStores[2].get(k)).collect(Collectors.toList()),
                    batchLoadExecutor);
    private static final BatchLoader<String, Map<String, Object>> batchLoaderL4 =
            keys -> CompletableFuture.supplyAsync(
                    () -> keys.stream().map(k -> levelStores[3].get(k)).collect(Collectors.toList()),
                    batchLoadExecutor);

    // ================ Benchmark methods ================

    @Benchmark
    @BenchmarkMode(Mode.Throughput)
    @OutputTimeUnit(TimeUnit.SECONDS)
    public ExecutionResult benchmarkThroughput() {