diff --git a/CMakeLists.txt b/CMakeLists.txt
index 27c29861..f5dcd324 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -56,6 +56,8 @@ if (BUILD_PEERPLAYS_TESTNET)
    set(GRAPHENE_EGENESIS_JSON "${CMAKE_CURRENT_SOURCE_DIR}/genesis-testnet.json" CACHE PATH "location of the genesis.json to embed in the executable" )
    #add_compile_definitions(BUILD_PEERPLAYS_TESTNET=1)
    add_definitions(-DBUILD_PEERPLAYS_TESTNET=1)
+   add_definitions(-DBOOST_MULTI_INDEX_ENABLE_INVARIANT_CHECKING=1)
+   add_definitions(-DBOOST_MULTI_INDEX_ENABLE_SAFE_MODE=1)
    message ("\n====================\nBuilding for Testnet\n====================\n")
 else (BUILD_PEERPLAYS_TESTNET)
    set(GRAPHENE_EGENESIS_JSON "${CMAKE_CURRENT_SOURCE_DIR}/genesis-mainnet.json" CACHE PATH "location of the genesis.json to embed in the executable" )
diff --git a/libraries/app/application.cpp b/libraries/app/application.cpp
index 19f1ed10..4fcd22e7 100644
--- a/libraries/app/application.cpp
+++ b/libraries/app/application.cpp
@@ -853,9 +853,10 @@ application::~application() {
       my->_p2p_network->close();
       my->_p2p_network.reset();
    }
-   if (my->_chain_db) {
-      my->_chain_db->close();
-   }
+   //if (my->_chain_db) {
+   //   my->_chain_db->close();
+   //   my->_chain_db.reset();
+   //}
 }
 
 void application::set_program_options(boost::program_options::options_description &cli,
@@ -1010,8 +1011,10 @@ void application::shutdown_plugins() {
 void application::shutdown() {
    if (my->_p2p_network)
       my->_p2p_network->close();
-   if (my->_chain_db)
+   if (my->_chain_db){
       my->_chain_db->close();
+      my->_chain_db.reset();
+   }
 }
 
 void application::initialize_plugins(const boost::program_options::variables_map &options) {
diff --git a/libraries/chain/db_init.cpp b/libraries/chain/db_init.cpp
index 724cad85..f1a74612 100644
--- a/libraries/chain/db_init.cpp
+++ b/libraries/chain/db_init.cpp
@@ -332,7 +332,7 @@ void database::initialize_evaluators()
 void database::initialize_indexes()
 {
    reset_indexes();
-   _undo_db.set_max_size( GRAPHENE_MIN_UNDO_HISTORY );
+   _undo_db.set_max_size( 100 /*GRAPHENE_MIN_UNDO_HISTORY*/ );
 
    //Protocol object indexes
    add_index< primary_index<asset_index, 13> >(); // 8192 assets per chunk
diff --git a/libraries/db/include/graphene/db/index.hpp b/libraries/db/include/graphene/db/index.hpp
index 1bc593f4..93b49fab 100644
--- a/libraries/db/include/graphene/db/index.hpp
+++ b/libraries/db/include/graphene/db/index.hpp
@@ -110,6 +110,7 @@ namespace graphene { namespace db {
          const object&              get( object_id_type id )const
          {
             auto maybe_found = find( id );
+	    ilog("get ID is ${id}", ("id", id));
             FC_ASSERT( maybe_found != nullptr, "Unable to find Object", ("id",id) );
             return *maybe_found;
          }
diff --git a/libraries/db/include/graphene/db/undo_database.hpp b/libraries/db/include/graphene/db/undo_database.hpp
index 0eb00f55..c7bb2de7 100644
--- a/libraries/db/include/graphene/db/undo_database.hpp
+++ b/libraries/db/include/graphene/db/undo_database.hpp
@@ -25,6 +25,9 @@
 #include <graphene/db/object.hpp>
 #include <deque>
 #include <fc/exception/exception.hpp>
+#include <fc/thread/spin_yield_lock.hpp>
+#include <fc/fwd.hpp>
+#include <fc/thread/unique_lock.hpp>
 
 namespace graphene { namespace db {
 
@@ -132,6 +135,8 @@ namespace graphene { namespace db {
          std::deque<undo_state>  _stack;
          object_database&        _db;
          size_t                  _max_size = 256;
+
+	 mutable fc::spin_yield_lock     _spin_yield;
    };
 
 } } // graphene::db
diff --git a/libraries/db/undo_database.cpp b/libraries/db/undo_database.cpp
index bffd761d..ee3fc11b 100644
--- a/libraries/db/undo_database.cpp
+++ b/libraries/db/undo_database.cpp
@@ -25,6 +25,8 @@
 #include <graphene/db/undo_database.hpp>
 #include <fc/reflect/variant.hpp>
 
+#include <fc/thread/spin_yield_lock.hpp>
+
 namespace graphene { namespace db {
 
 void undo_database::enable()  { _disabled = false; }
@@ -44,6 +46,8 @@ undo_database::session::~session() {
 
 undo_database::session undo_database::start_undo_session( bool force_enable )
 {
+   synchronized(_spin_yield)
+
    if( _disabled && !force_enable ) return session(*this);
    bool disable_on_exit = _disabled  && force_enable;
    if( force_enable ) 
@@ -58,6 +62,8 @@ undo_database::session undo_database::start_undo_session( bool force_enable )
 }
 void undo_database::on_create( const object& obj )
 {
+   synchronized(_spin_yield)
+
    if( _disabled ) return;
 
    if( _stack.empty() )
@@ -73,6 +79,8 @@ void undo_database::on_modify( const object& obj )
 {
    if( _disabled ) return;
 
+   synchronized(_spin_yield)
+
    if( _stack.empty() )
       _stack.emplace_back();
    auto& state = _stack.back();
@@ -86,6 +94,8 @@ void undo_database::on_remove( const object& obj )
 {
    if( _disabled ) return;
 
+   synchronized(_spin_yield)
+
    if( _stack.empty() )
       _stack.emplace_back();
    undo_state& state = _stack.back();
@@ -105,7 +115,9 @@ void undo_database::on_remove( const object& obj )
 }
 
 void undo_database::undo()
-{ try {
+{ 
+  synchronized(_spin_yield)
+  try {
    FC_ASSERT( !_disabled );
    FC_ASSERT( _active_sessions > 0 );
    disable();
@@ -136,6 +148,8 @@ void undo_database::undo()
 
 void undo_database::merge()
 {
+   synchronized(_spin_yield)
+
    FC_ASSERT( _active_sessions > 0 );
    if( _active_sessions == 1 && _stack.size() == 1 )
    {
@@ -256,12 +270,16 @@ void undo_database::merge()
 }
 void undo_database::commit()
 {
+   synchronized(_spin_yield)
+
    FC_ASSERT( _active_sessions > 0 );
    --_active_sessions;
 }
 
 void undo_database::pop_commit()
 {
+   synchronized(_spin_yield)
+
    FC_ASSERT( _active_sessions == 0 );
    FC_ASSERT( !_stack.empty() );
 
@@ -299,6 +317,8 @@ void undo_database::pop_commit()
 }
 const undo_state& undo_database::head()const
 {
+   synchronized(_spin_yield)
+
    FC_ASSERT( !_stack.empty() );
    return _stack.back();
 }
diff --git a/libraries/fc b/libraries/fc
index 6171e973..711b04fb 160000
--- a/libraries/fc
+++ b/libraries/fc
@@ -1 +1 @@
-Subproject commit 6171e973c7fcfc9e0a39eaee2f05da84416a90e6
+Subproject commit 711b04fb4f21bcaf8fdf00f51f4d6410849bec92