Added ability to use a custom executor such as graphql-jit

.changeset/good-spies-share.md

@@ -0,0 +1,46 @@
+---
+'@apollo/server': minor
+---
+
+# Added ability to use a custom executor such as graphql-jit
+
+Apollo Server uses graphql-js behind the scenes when executing graphql queries.
+If you would like to use a custom executor, such as
+[graphql-jit](https://github.com/zalando-incubator/graphql-jit/tree/main),
+you can swap in a `customExecutor`. This can result in significant performance
+gains when used in combination with `staticOnly` cache control hints, especially with larger response sizes.
+
+Note that this cannot be used when using the `gateway` option.
+
+```ts
+import { compileQuery, isCompiledQuery } from 'graphql-jit';
+import { lru } from 'tiny-lru';
+
+const executor = (schema: GraphQLSchema, cacheSize = 2014, compilerOpts = {}) => {
+  const cache = lru(cacheSize);
+  return async ({ contextValue, document, operationName, request, queryHash }) => {
+    const prefix = operationName || 'NotParametrized';
+    const cacheKey = `${prefix}-${queryHash}`;
+    let compiledQuery = cache.get(cacheKey);
+    if (!compiledQuery) {
+      const compilationResult = compileQuery(schema, document, operationName || undefined, compilerOpts);
+      if (isCompiledQuery(compilationResult)) {
+        compiledQuery = compilationResult;
+        cache.set(cacheKey, compiledQuery);
+      } else {
+        // ...is ExecutionResult
+        return compilationResult;
+      }
+    }
+
+    return compiledQuery.query(undefined, contextValue, request.variables || {});
+  };
+};
+
+const schema = buildSubgraphSchema([{ typeDefs, resolvers }]);
+
+const server = new ApolloServer<BaseContext>({
+  schema,
+  customExecutor: executor(schema),
+});
+```

docs/source/api/apollo-server.mdx

@@ -421,6 +421,27 @@ You can also manually call `stop()` in other contexts. Note that `stop()` is asy
 </td>
 </tr>
 
+
+<tr>
+<td>
+
+###### `customExecutor`
+
+`Object`
+
+</td>
+<td>
+
+Apollo Server uses graphql-js behind the scenes when executing graphql queries.
+If you would like to use a [custom executor](/apollo-server/performance/custom-executor), such as
+[graphql-jit](https://github.com/zalando-incubator/graphql-jit/tree/main),
+you can swap in a `customExecutor`.
+
+Note that this cannot be used when using the `gateway` option.
+
+</td>
+</tr>
+
 <tr>
 <td colspan="2">
 

docs/source/config.json

@@ -45,7 +45,8 @@
       "Caching": "/performance/caching",
       "Cache Backends": "/performance/cache-backends",
       "Response Cache Eviction": "/performance/response-cache-eviction",
-      "Automatic Persisted Queries": "/performance/apq"
+      "Automatic Persisted Queries": "/performance/apq",
+      "Using a Custom Executor": "/performance/custom-executor"
     },
     "Security": {
       "Authentication and Authorization": "/security/authentication",

docs/source/performance/custom-executor.mdx

@@ -0,0 +1,49 @@
+---
+title: Using a Custom Executor
+description: How to configure Apollo Server to use a custom executor
+---
+
+Apollo Server uses graphql-js behind the scenes when executing graphql queries.
+If you would like to use a custom executor, such as
+[graphql-jit](https://github.com/zalando-incubator/graphql-jit/tree/main),
+you can swap in a `customExecutor`. This can result in significant performance
+gains when used in combination with `staticOnly` cache control hints, especially with larger response sizes.
+
+Note that this cannot be used when using the `gateway` option.
+
+![graph showing how Apollo Server performance with increasing payload size with various setups](graphqlhit.png)
+
+## Example using graphql-jit
+
+```ts
+import { compileQuery, isCompiledQuery } from 'graphql-jit';
+import { lru } from 'tiny-lru';
+
+const executor = (schema: GraphQLSchema, cacheSize = 2014, compilerOpts = {}) => {
+  const cache = lru(cacheSize);
+  return async ({ contextValue, document, operationName, request, queryHash }) => {
+    const prefix = operationName || 'NotParametrized';
+    const cacheKey = `${prefix}-${queryHash}`;
+    let compiledQuery = cache.get(cacheKey);
+    if (!compiledQuery) {
+      const compilationResult = compileQuery(schema, document, operationName || undefined, compilerOpts);
+      if (isCompiledQuery(compilationResult)) {
+        compiledQuery = compilationResult;
+        cache.set(cacheKey, compiledQuery);
+      } else {
+        // ...is ExecutionResult
+        return compilationResult;
+      }
+    }
+
+    return compiledQuery.query(undefined, contextValue, request.variables || {});
+  };
+};
+
+const schema = buildSubgraphSchema([{ typeDefs, resolvers }]);
+
+const server = new ApolloServer<BaseContext>({
+  schema,
+  customExecutor: executor(schema),
+});
+```