diff --git a/src/odbc/ejabberd_odbc.erl b/src/odbc/ejabberd_odbc.erl
index 09a0ec8c9..046690cda 100644
--- a/src/odbc/ejabberd_odbc.erl
+++ b/src/odbc/ejabberd_odbc.erl
@@ -70,8 +70,8 @@ start_link(Host, StartInterval) ->
     gen_server:start_link(ejabberd_odbc, [Host, StartInterval], []).
 
 sql_query(Host, Query) ->
-    gen_server:call(ejabberd_odbc_sup:get_random_pid(Host),
-		    {sql_query, Query}, ?TRANSACTION_TIMEOUT).
+    Msg = {sql_query, Query},
+    sql_call(Host, Msg,).
 
 %% SQL transaction based on a list of queries
 %% This function automatically
@@ -85,13 +85,24 @@ sql_transaction(Host, Queries) when is_list(Queries) ->
     sql_transaction(Host, F);
 %% SQL transaction, based on a erlang anonymous function (F = fun)
 sql_transaction(Host, F) ->
-    gen_server:call(ejabberd_odbc_sup:get_random_pid(Host),
-		    {sql_transaction, F}, ?TRANSACTION_TIMEOUT).
+    Msg = {sql_transaction, F},
+    sql_call(Host, Msg).
 
 %% SQL bloc, based on a erlang anonymous function (F = fun)
 sql_bloc(Host, F) ->
-    gen_server:call(ejabberd_odbc_sup:get_random_pid(Host),
-		    {sql_bloc, F}, ?TRANSACTION_TIMEOUT).
+    Msg = {sql_bloc, F},
+    sql_call(Host, Msg).
+
+sql_call(Host, Msg) ->
+    case get(?STATE_KEY) of
+        undefined ->
+            gen_server:call(ejabberd_odbc_sup:get_random_pid(Host),
+                            Msg, ?TRANSACTION_TIMEOUT);
+        State ->
+            %% Query, Transaction or Bloc nested inside transaction
+            nested_op(Msg, State)
+    end.
+
 
 %% This function is intended to be used from inside an sql_transaction:
 sql_query_t(Query) ->
@@ -173,42 +184,8 @@ init([Host, StartInterval]) ->
 %%          {stop, Reason, Reply, State}   | (terminate/2 is called)
 %%          {stop, Reason, State}            (terminate/2 is called)
 %%----------------------------------------------------------------------
-handle_call({sql_query, Query}, _From, State) ->
-    case sql_query_internal(State, Query) of
-	% error returned by MySQL driver
-	{error, "query timed out"} = Reply ->
-	    {stop, timeout, Reply, State};
-	% error returned by MySQL driver
-	{error, "Failed sending data on socket"++_} = Reply ->
-	    {stop, closed, Reply, State};
-	Reply ->
-	    {reply, Reply, State}
-    end;
-handle_call({sql_transaction, F}, _From, State) ->
-    case execute_transaction(State, F, ?MAX_TRANSACTION_RESTARTS, "") of
-	% error returned by MySQL driver
-	{error, "query timed out"} ->
-	    {stop, timeout, State};
-	% error returned by MySQL driver
-	{error, "Failed sending data on socket"++_} = Reply ->
-	    {stop, closed, Reply, State};
-	Reply ->
-	    {reply, Reply, State}
-    end;
-handle_call({sql_bloc, F}, _From, State) ->
-    case execute_bloc(State, F) of
-	% error returned by MySQL driver
-	{error, "query timed out"} ->
-	    {stop, timeout, State};
-	% error returned by MySQL driver
-	{error, "Failed sending data on socket"++_} = Reply ->
-	    {stop, closed, Reply, State};
-	Reply ->
-	    {reply, Reply, State}
-    end;
-handle_call(_Request, _From, State) ->
-    Reply = ok,
-    {reply, Reply, State}.
+handle_call(Command, _From, State) ->
+    dispatch_sql_command(Command, State).
 
 %%----------------------------------------------------------------------
 %% Func: handle_cast/2
@@ -256,14 +233,36 @@ terminate(_Reason, State) ->
 %%%----------------------------------------------------------------------
 %%% Internal functions
 %%%----------------------------------------------------------------------
+dispatch_sql_command({sql_query, Query}, State) ->
+    abort_on_driver_error(sql_query_internal(State, Query), State);
+dispatch_sql_command({sql_transaction, F}, State) ->
+    abort_on_driver_error(
+      execute_transaction(State, F, ?MAX_TRANSACTION_RESTARTS, ""), State);
+dispatch_sql_command({sql_bloc, F}, State) ->
+    abort_on_driver_error(execute_bloc(State, F), State);
+dispatch_sql_command(Request, State) ->
+    ?WARNING_MSG("Unexpected call ~p.", [Request]),
+    {reply, ok, State}.
+
 sql_query_internal(State, Query) ->
-    case State#state.db_type of
-	odbc ->
-	    odbc:sql_query(State#state.db_ref, Query);
-	pgsql ->
-	    pgsql_to_odbc(pgsql:squery(State#state.db_ref, Query));
-	mysql ->
-	    mysql_to_odbc(mysql_conn:fetch(State#state.db_ref, Query, self()))
+    Nested = case get(?STATE_KEY) of
+		 undefined -> put(?STATE_KEY, State), false;
+		 _State -> true
+	     end,
+    Result = case State#state.db_type of
+		 odbc ->
+		     odbc:sql_query(State#state.db_ref, Query);
+		 pgsql ->
+		     pgsql_to_odbc(pgsql:squery(State#state.db_ref, Query));
+		 mysql ->
+		     ?DEBUG("MySQL, Send query~n~p~n", [Query]),
+		     R = mysql_to_odbc(mysql_conn:fetch(State#state.db_ref, Query, self())),
+		     ?INFO_MSG("MySQL, Received result~n~p~n", [R]),
+		     R
+	     end,
+    case Nested of
+	true -> Result;
+	false -> erase(?STATE_KEY), Result
     end.
 
 execute_transaction(State, _F, 0, Reason) ->
@@ -277,30 +276,69 @@ execute_transaction(State, _F, 0, Reason) ->
     sql_query_internal(State, "rollback;"),
     {aborted, restarts_exceeded};
 execute_transaction(State, F, NRestarts, _Reason) ->
-    put(?STATE_KEY, State),
-    sql_query_internal(State, "begin;"),
-    case catch F() of
-	{aborted, Reason} ->
-	    execute_transaction(State, F, NRestarts - 1, Reason);
-	{'EXIT', Reason} ->
-	    sql_query_internal(State, "rollback;"),
-	    {aborted, Reason};
-	Res ->
-	    sql_query_internal(State, "commit;"),
-	    {atomic, Res}
+    Nested = case get(?STATE_KEY) of
+		 undefined ->
+		     put(?STATE_KEY, State),
+		     sql_query_internal(State, "begin;"),
+		     false;
+		 _State ->
+		     true
+	     end,
+    Result = case catch F() of
+		 {aborted, Reason} ->
+		     execute_transaction(State, F, NRestarts - 1, Reason);
+		 {'EXIT', Reason} ->
+		     sql_query_internal(State, "rollback;"),
+		     {aborted, Reason};
+		 Res  ->
+		     {atomic, Res}
+			     end,
+    case Nested of
+	true -> Result;
+	false -> sql_query_internal(State, "commit;"), erase(?STATE_KEY), Result
     end.
 
 execute_bloc(State, F) ->
-    put(?STATE_KEY, State),
-    case catch F() of
-	{aborted, Reason} ->
-	    {aborted, Reason};
-	{'EXIT', Reason} ->
-	    {aborted, Reason};
-	Res ->
-	    {atomic, Res}
+    Nested = case get(?STATE_KEY) of
+		 undefined -> put(?STATE_KEY, State), false;
+		 _State -> true
+	     end,
+    Result = case catch F() of
+		 {aborted, Reason} ->
+		     {aborted, Reason};
+		 {'EXIT', Reason} ->
+		     {aborted, Reason};
+		 Res ->
+		     {atomic, Res}
+	     end,
+    case Nested of
+	true -> Result;
+	false -> erase(?STATE_KEY), Result
     end.
 
+nested_op(Op, State) ->
+    case dispatch_sql_command(Op, State) of
+	{reply, Res, NewState} ->
+	    put(?STATE_KEY, NewState),
+	    Res;
+	{stop, _Reason, Reply, NewState} ->
+	    put(?STATE_KEY, NewState),
+	    throw({aborted, Reply});
+	{noreply, NewState} ->
+	    put(?STATE_KEY, NewState),
+	    exit({bad_op_in_nested_txn, Op})
+    end.
+
+abort_on_driver_error({error, "query timed out"} = Reply, State) ->
+    %% mysql driver error
+    {stop, timeout, Reply, State};
+abort_on_driver_error({error, "Failed sending data on socket"++_} = Reply, State) ->
+    %% mysql driver error
+    {stop, closed, Reply, State};
+abort_on_driver_error(Reply, State) ->
+    {reply, Reply, State}.
+
+
 %% == pure ODBC code
 
 %% part of init/1