diff --git a/src/util/oddbapp.rb b/src/util/oddbapp.rb
index bfb9fa0..5b9ce46 100644
--- a/src/util/oddbapp.rb
+++ b/src/util/oddbapp.rb
@@ -1,7 +1,14 @@
 #!/usr/bin/env ruby
+# encoding: utf-8
 # OddbApp -- oddb.org -- 10.10.2011 -- mhatakeyama@ywesee.com
 # OddbApp -- oddb.org -- 21.06.2010 -- hwyss@ywesee.com
 
+require 'pp'
+class NilClass
+  def odba_store
+  end
+end
+
 require 'odba'
 require 'odba/index_definition'
 require 'odba/drbwrapper'
@@ -1776,9 +1783,13 @@ module ODDB
       _migrate_to_utf8([object], {}, iconv)
     end
     def migrate_to_utf8
+
+      @migrate_mutex = Mutex.new
+
       iconv = ::Iconv.new 'UTF-8//TRANSLIT//IGNORE', 'ISO-8859-1'
       ODBA.cache.retire_age = 5
-      ODBA.cache.cleaner_step = 100000
+#      ODBA.cache.cleaner_step = 100000
+      ODBA.cache.cleaner_step = 1
       system = @system.odba_instance
       table = { system.odba_id => true, :serialized => {} }
       table.store :finalizer, proc { |object_id|
@@ -1794,7 +1805,11 @@ module ODDB
       end
     end
     def _migrate_to_utf8 queue, table, iconv, opts={}
+
+      @migrate_mutex ||= Mutex.new
+
       obj = queue.shift
+
       if obj.is_a?(Numeric)
         begin
           obj = ODBA.cache.fetch obj
@@ -1804,19 +1819,40 @@ module ODDB
       else
         obj = obj.odba_instance
       end
-      _migrate_obj_to_utf8 obj, queue, table, iconv, opts
-      obj.odba_store unless obj.odba_unsaved?
+      #_migrate_obj_to_utf8 obj, queue, table, iconv, opts
+      obj = _migrate_obj_to_utf8 obj, queue, table, iconv, opts
+
+# save object here
+      @migrate_mutex.synchronize {
+      if obj
+        @start_time ||= Time.now
+        @count ||= 0
+          obj.odba_store unless obj.odba_unsaved?
+        print "saved: ", @count+=1, "\todba_id:%15s" % obj.odba_id, "\tclass:%20s" % obj.class.to_s, "\t%.2f" % ((Time.now - @start_time)/3600), " [h]\n"
+      end
+      }
     end
     def _migrate_obj_to_utf8 obj, queue, table, iconv, opts={}
-      obj.instance_variables.each do |name|
+      #obj.instance_variables.each do |name|
+      obj.instance_variables.sort.each do |name|
         child = obj.instance_variable_get name
+      begin
         if child.respond_to?(:odba_unsaved?) && !child.odba_unsaved? \
           && obj.respond_to?(:odba_serializables) \
           && obj.odba_serializables.include?(name)
           child.instance_variable_set '@odba_persistent', nil
         end
+
+# recursive 
         child = _migrate_child_to_utf8 child, queue, table, iconv, opts
-        obj.instance_variable_set name, child
+
+# save children (instance_variables) 
+        #obj.instance_variable_set name, child 
+        obj.instance_variable_set name, child if child
+      rescue => e
+        p e
+      end
+
       end
       if obj.is_a?(Array)
         obj.collect! do |child|
@@ -1831,6 +1867,7 @@ module ODDB
           obj.default = _migrate_child_to_utf8 obj.default, queue, table, iconv, opts
         end
       end
+
       obj
     end
     def _migrate_child_to_utf8 child, queue, table, iconv, opts={}
@@ -1849,7 +1886,8 @@ module ODDB
           end
         end
       when String
-        child = iconv.iconv(child)
+#        child = iconv.iconv(child)
+        child.force_encoding('utf-8')
       when ODDB::Text::Section, ODDB::Text::Paragraph, ODDB::PatinfoDocument,
            ODDB::PatinfoDocument2001, ODDB::Text::Table, ODDB::Text::Cell,
            ODDB::Analysis::Permission, ODDB::Interaction::AbstractLink,