New isolate for the SDK index in the search instance.

app/lib/fake/server/fake_search_service.dart

@@ -39,7 +39,7 @@ class FakeSearchService {
         storage: _storage,
         cloudCompute: _cloudCompute,
         fn: () async {
-          registerSdkMemIndex(await createSdkMemIndex());
+          registerSdkIndex(await createSdkMemIndex());
           final handler = wrapHandler(_logger, searchServiceHandler);
           final server = await IOServer.bind('localhost', port);
           serveRequests(server.server, (request) async {

app/lib/search/backend.dart

@@ -619,18 +619,34 @@ class _CombinedSearchIndex implements SearchIndex {
   IndexInfo indexInfo() => _packageIndexHolder._index.indexInfo();
 
   @override
-  PackageSearchResult search(ServiceSearchQuery query) {
+  Future<PackageSearchResult> search(ServiceSearchQuery query) async {
     final combiner = SearchResultCombiner(
-      primaryIndex: _packageIndexHolder._index,
-      sdkMemIndex: sdkMemIndex,
+      primaryIndex: _packageIndexHolder,
+      sdkIndex: sdkIndex,
     );
-    return combiner.search(query);
+    return await combiner.search(query);
   }
 }
 
 /// Holds an immutable [InMemoryPackageIndex] that is the actual active search index.
-class PackageIndexHolder {
+class PackageIndexHolder implements SearchIndex {
   var _index = InMemoryPackageIndex(documents: const []);
+
+  @override
+  bool isReady() => indexInfo().isReady;
+
+  @override
+  IndexInfo indexInfo() => _index.indexInfo();
+
+  @override
+  PackageSearchResult search(ServiceSearchQuery query) {
+    return _index.search(query);
+  }
+
+  /// Updates the active package index with [newIndex].
+  void updatePackageIndex(InMemoryPackageIndex newIndex) {
+    _index = newIndex;
+  }
 }
 
 /// Updates the active package index with [newIndex].

app/lib/search/result_combiner.dart

@@ -2,36 +2,51 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'dart:async';
+
 import 'package:_pub_shared/search/tags.dart';
 import 'package:collection/collection.dart';
 
-import 'mem_index.dart';
 import 'sdk_mem_index.dart';
 import 'search_service.dart';
 
 /// Combines the results from the primary package index and the optional Dart
 /// SDK index.
-class SearchResultCombiner {
-  final InMemoryPackageIndex primaryIndex;
-  final SdkMemIndex? sdkMemIndex;
+class SearchResultCombiner implements SearchIndex {
+  final SearchIndex primaryIndex;
+  final SdkIndex? sdkIndex;
 
   SearchResultCombiner({
     required this.primaryIndex,
-    required this.sdkMemIndex,
+    required this.sdkIndex,
   });
 
-  PackageSearchResult search(ServiceSearchQuery query) {
-    final primaryResult = primaryIndex.search(query);
-    if (!query.includeSdkResults) {
-      return primaryResult;
+  @override
+  FutureOr<IndexInfo> indexInfo() async {
+    return await primaryIndex.indexInfo();
+  }
+
+  @override
+  FutureOr<bool> isReady() async {
+    return await primaryIndex.isReady();
+  }
+
+  @override
+  Future<PackageSearchResult> search(ServiceSearchQuery query) async {
+    if (sdkIndex == null || !query.includeSdkResults) {
+      return await primaryIndex.search(query);
     }
 
     final queryFlutterSdk = query.tagsPredicate.hasNoTagPrefix('sdk:') ||
         query.tagsPredicate.hasTag(SdkTag.sdkFlutter);
-    final sdkLibraryHits = sdkMemIndex
-            ?.search(query.query!, limit: 2, skipFlutter: !queryFlutterSdk)
-            .toList() ??
-        <SdkLibraryHit>[];
+    final results = await Future.wait([
+      Future(() => primaryIndex.search(query)),
+      Future(() => sdkIndex!
+          .search(query.query!, limit: 2, skipFlutter: !queryFlutterSdk)),
+    ]);
+    final primaryResult = results[0] as PackageSearchResult;
+    final sdkLibraryHits = results[1] as List<SdkLibraryHit>;
+
     if (sdkLibraryHits.isNotEmpty) {
       // Do not display low SDK scores if the package hits are more relevant on the page.
       //

app/lib/search/sdk_mem_index.dart

@@ -17,15 +17,15 @@ import 'token_index.dart';
 
 export 'package:pana/src/dartdoc/dartdoc_index.dart';
 
-/// Sets the SDK in-memory index.
-void registerSdkMemIndex(SdkMemIndex? index) {
+/// Sets the SDK index.
+void registerSdkIndex(SdkIndex? index) {
   if (index != null) {
-    ss.register(#_sdkMemIndex, index);
+    ss.register(#_sdkIndex, index);
   }
 }
 
 /// The active SDK in-memory index.
-SdkMemIndex? get sdkMemIndex => ss.lookup(#_sdkMemIndex) as SdkMemIndex?;
+SdkIndex? get sdkIndex => ss.lookup(#_sdkIndex) as SdkIndex?;
 
 /// Results from these libraries are ranked with lower score and
 /// will be displayed only if the query has the library name, or

app/lib/service/entrypoint/_isolate.dart

@@ -176,10 +176,11 @@ Future<IsolateRunner> startWorkerIsolate({
 Future<IsolateRunner> startQueryIsolate({
   required Logger logger,
   required Uri spawnUri,
+  required String kind,
 }) async {
   final worker = IsolateRunner.uri(
     logger: logger,
-    kind: 'query',
+    kind: kind,
     spawnUri: spawnUri,
   );
   await worker.start(1);

app/lib/service/entrypoint/search.dart

@@ -8,6 +8,8 @@ import 'dart:math';
 import 'package:args/command_runner.dart';
 import 'package:gcloud/service_scope.dart';
 import 'package:logging/logging.dart';
+import 'package:pub_dev/search/result_combiner.dart';
+import 'package:pub_dev/service/entrypoint/sdk_isolate_index.dart';
 import 'package:pub_dev/service/entrypoint/search_index.dart';
 
 import '../../search/backend.dart';
@@ -36,14 +38,29 @@ class SearchCommand extends Command {
 
     envConfig.checkServiceEnvironment(name);
     await withServices(() async {
-      final index = await startQueryIsolate(
+      final packageIsolate = await startQueryIsolate(
         logger: _logger,
+        kind: 'package',
         spawnUri:
             Uri.parse('package:pub_dev/service/entrypoint/search_index.dart'),
       );
-      registerScopeExitCallback(index.close);
+      registerScopeExitCallback(packageIsolate.close);
 
-      registerSearchIndex(LatencyAwareSearchIndex(IsolateSearchIndex(index)));
+      final sdkIsolate = await startQueryIsolate(
+        logger: _logger,
+        kind: 'sdk',
+        spawnUri: Uri.parse(
+            'package:pub_dev/service/entrypoint/sdk_isolate_index.dart'),
+      );
+      registerScopeExitCallback(sdkIsolate.close);
+
+      registerSearchIndex(
+        SearchResultCombiner(
+          primaryIndex:
+              LatencyAwareSearchIndex(IsolateSearchIndex(packageIsolate)),
+          sdkIndex: SdkIsolateIndex(sdkIsolate),
+        ),
+      );
 
       void scheduleRenew() {
         scheduleMicrotask(() async {
@@ -53,7 +70,7 @@ class SearchCommand extends Command {
           await Future.delayed(delay);
 
           // create a new index and handover with a 2-minute maximum wait
-          await index.renew(count: 1, wait: Duration(minutes: 2));
+          await packageIsolate.renew(count: 1, wait: Duration(minutes: 2));
 
           // schedule the renewal again
           scheduleRenew();

app/lib/service/entrypoint/search_index.dart

@@ -8,7 +8,6 @@ import 'dart:convert';
 import 'package:gcloud/service_scope.dart';
 import 'package:logging/logging.dart';
 import 'package:pub_dev/search/backend.dart';
-import 'package:pub_dev/search/sdk_mem_index.dart';
 import 'package:pub_dev/search/search_service.dart';
 import 'package:pub_dev/search/updater.dart';
 import 'package:pub_dev/service/entrypoint/_isolate.dart';
@@ -35,7 +34,6 @@ Future<void> main(List<String> args, var message) async {
   }
   await fork(() async {
     await servicesWrapperFn(() async {
-      registerSdkMemIndex(await createSdkMemIndex());
       await indexUpdater.init();
 
       await runIsolateFunctions(

app/test/search/result_combiner_test.dart

@@ -5,6 +5,7 @@
 import 'dart:convert';
 
 import 'package:_pub_shared/search/search_form.dart';
+import 'package:pub_dev/search/backend.dart';
 import 'package:pub_dev/search/mem_index.dart';
 import 'package:pub_dev/search/result_combiner.dart';
 import 'package:pub_dev/search/sdk_mem_index.dart';
@@ -13,7 +14,7 @@ import 'package:test/test.dart';
 
 void main() {
   group('ResultCombiner', () {
-    final primaryIndex = InMemoryPackageIndex(
+    final packageIndex = InMemoryPackageIndex(
       documents: [
         PackageDocument(
           package: 'stringutils',
@@ -27,9 +28,10 @@ void main() {
         ),
       ],
     );
+    final primaryIndex = PackageIndexHolder()..updatePackageIndex(packageIndex);
     final combiner = SearchResultCombiner(
       primaryIndex: primaryIndex,
-      sdkMemIndex: SdkMemIndex(
+      sdkIndex: SdkMemIndex(
         dartIndex: DartdocIndex.fromJsonList([
           {
             'name': 'dart:core',
@@ -73,7 +75,7 @@ void main() {
     );
 
     test('non-text ranking', () async {
-      final results = combiner
+      final results = await combiner
           .search(ServiceSearchQuery.parse(order: SearchOrder.downloads));
       expect(json.decode(json.encode(results.toJson())), {
         'timestamp': isNotNull,
@@ -87,7 +89,7 @@ void main() {
 
     test('no actual text query', () async {
       final results =
-          combiner.search(ServiceSearchQuery.parse(query: 'package:s'));
+          await combiner.search(ServiceSearchQuery.parse(query: 'package:s'));
       expect(json.decode(json.encode(results.toJson())), {
         'timestamp': isNotNull,
         'totalCount': 1,
@@ -100,7 +102,7 @@ void main() {
 
     test('search: substring', () async {
       final results =
-          combiner.search(ServiceSearchQuery.parse(query: 'substring'));
+          await combiner.search(ServiceSearchQuery.parse(query: 'substring'));
       expect(json.decode(json.encode(results.toJson())), {
         'timestamp': isNotNull,
         'totalCount': 1,

app/test/service/entrypoint/search_index_test.dart

@@ -34,7 +34,7 @@ void main() {
       final rs =
           await searchIndex.search(ServiceSearchQuery.parse(query: 'json'));
       expect(rs.errorMessage, isNull);
-      expect(rs.sdkLibraryHits, isNotEmpty);
+      expect(rs.sdkLibraryHits, isEmpty);
       expect(rs.packageHits, isEmpty);
     }, timeout: Timeout(Duration(minutes: 5)));
   });