Merge "Always use a thread pool for interactive indexing"

gerrit-server/src/main/java/com/google/gerrit/server/index/IndexModule.java

@@ -140,7 +140,7 @@ public class IndexModule extends LifecycleModule {
       threads = config.getInt("index", null, "threads", 0);
     }
     if (threads <= 0) {
-      return MoreExecutors.newDirectExecutorService();
+      threads = Runtime.getRuntime().availableProcessors() / 2 + 1;
     }
     return MoreExecutors.listeningDecorator(
         workQueue.createQueue(threads, "Index-Interactive"));