diff --git a/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexProjectHandler.java b/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexProjectHandler.java
index c3ce6433c228..c79aca0c1aaf 100644
--- a/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexProjectHandler.java
+++ b/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexProjectHandler.java
@@ -22,7 +22,9 @@ package com.intellij.util.indexing;
 import com.intellij.ide.IdeBundle;
 import com.intellij.ide.caches.FileContent;
 import com.intellij.ide.startup.StartupManagerEx;
+import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.components.AbstractProjectComponent;
+import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.fileTypes.FileTypeManager;
 import com.intellij.openapi.progress.ProgressIndicator;
 import com.intellij.openapi.project.*;
@@ -42,6 +44,7 @@ import org.jetbrains.annotations.Nullable;
 import java.util.Collection;
 
 public class FileBasedIndexProjectHandler extends AbstractProjectComponent implements IndexableFileSet {
+  private static final Logger LOG = Logger.getInstance("#com.intellij.util.indexing.FileBasedIndexProjectHandler");
   private final FileBasedIndexImpl myIndex;
   private final ProjectRootManagerEx myRootManager;
   private final FileTypeManager myFileTypeManager;
@@ -52,6 +55,18 @@ public class FileBasedIndexProjectHandler extends AbstractProjectComponent imple
     myRootManager = rootManager;
     myFileTypeManager = ftManager;
 
+    if (ApplicationManager.getApplication().isInternal()) {
+      project.getMessageBus().connect().subscribe(DumbService.DUMB_MODE, new DumbService.DumbModeListener() {
+
+        public void enteredDumbMode() {
+        }
+
+        public void exitDumbMode() {
+          LOG.info("Has changed files: " + (createChangedFilesIndexingTask(project) != null) + "; project=" + project);
+        }
+      });
+    }
+
     final StartupManagerEx startupManager = (StartupManagerEx)StartupManager.getInstance(project);
     if (startupManager != null) {
       startupManager.registerPreStartupActivity(new Runnable() {
diff --git a/platform/platform-impl/src/com/intellij/ide/startup/impl/StartupManagerImpl.java b/platform/platform-impl/src/com/intellij/ide/startup/impl/StartupManagerImpl.java
index 1eae4c287c1d..eb64c824b801 100644
--- a/platform/platform-impl/src/com/intellij/ide/startup/impl/StartupManagerImpl.java
+++ b/platform/platform-impl/src/com/intellij/ide/startup/impl/StartupManagerImpl.java
@@ -262,10 +262,17 @@ public class StartupManagerImpl extends StartupManagerEx {
               }
             });
           }
+
+          @Override
+          public String toString() {
+            return "initial refresh";
+          }
         });
       }
 
-      dumbService.queueCacheUpdateInDumbMode(myCacheUpdaters);
+      if (!myCacheUpdaters.isEmpty()) {
+        dumbService.queueCacheUpdateInDumbMode(myCacheUpdaters);
+      }
     }
     catch (ProcessCanceledException e) {
       throw e;
diff --git a/platform/platform-impl/src/com/intellij/openapi/project/CacheUpdateRunner.java b/platform/platform-impl/src/com/intellij/openapi/project/CacheUpdateRunner.java
index 7866cdec5da5..25c312a08131 100644
--- a/platform/platform-impl/src/com/intellij/openapi/project/CacheUpdateRunner.java
+++ b/platform/platform-impl/src/com/intellij/openapi/project/CacheUpdateRunner.java
@@ -34,6 +34,7 @@ import com.intellij.util.Consumer;
 import gnu.trove.THashSet;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Set;
 import java.util.concurrent.Future;
@@ -52,6 +53,11 @@ public class CacheUpdateRunner {
     myUpdaters = updaters;
   }
 
+  @Override
+  public String toString() {
+    return new ArrayList<CacheUpdater>(myUpdaters).toString();
+  }
+
   public int queryNeededFiles(@NotNull ProgressIndicator indicator) {
     // can be queried twice in DumbService  
     return getSession(indicator).getFilesToUpdate().size();
diff --git a/platform/platform-impl/src/com/intellij/openapi/project/DumbServiceImpl.java b/platform/platform-impl/src/com/intellij/openapi/project/DumbServiceImpl.java
index 4cd56c52b548..f71eb5fef698 100644
--- a/platform/platform-impl/src/com/intellij/openapi/project/DumbServiceImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/project/DumbServiceImpl.java
@@ -97,6 +97,11 @@ public class DumbServiceImpl extends DumbService {
       public void canceled() {
 
       }
+
+      @Override
+      public String toString() {
+        return task.toString();
+      }
     };
     queueCacheUpdateInDumbMode(Arrays.asList(wrapper));
   }
@@ -258,6 +263,8 @@ public class DumbServiceImpl extends DumbService {
     myDumb = false;
     if (myProject.isDisposed()) return;
 
+    if (ApplicationManager.getApplication().isInternal()) LOG.info("updateFinished");
+
     try {
       myPublisher.exitDumbMode();
       FileEditorManagerEx.getInstanceEx(myProject).refreshIcons();
@@ -425,6 +432,7 @@ public class DumbServiceImpl extends DumbService {
         private void runAction(ProgressIndicator indicator, CacheUpdateRunner updateRunner) {
           while (updateRunner != null) {
             try {
+              if (ApplicationManager.getApplication().isInternal()) LOG.info("Running dumb mode task: " + updateRunner);
               indicator.checkCanceled();
               indicator.setIndeterminate(true);
               indicator.setText(IdeBundle.message("progress.indexing.scanning"));
diff --git a/platform/platform-impl/src/com/intellij/openapi/project/impl/ProjectManagerImpl.java b/platform/platform-impl/src/com/intellij/openapi/project/impl/ProjectManagerImpl.java
index 63cfad0e25f9..8fd90f6b8215 100644
--- a/platform/platform-impl/src/com/intellij/openapi/project/impl/ProjectManagerImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/project/impl/ProjectManagerImpl.java
@@ -419,6 +419,11 @@ public class ProjectManagerImpl extends ProjectManagerEx implements NamedJDOMExt
       public void performInDumbMode(@NotNull ProgressIndicator indicator) {
         waitForFileWatcher(indicator);
       }
+
+      @Override
+      public String toString() {
+        return "wait for file watcher";
+      }
     });
 
     final StartupManagerImpl startupManager = (StartupManagerImpl)StartupManager.getInstance(project);