anchor.diff:  	    {reply, {error, {no_connection_in_pool, PoolId}}, State}
       end.
   
  -call_server(Msg, Timeout) ->
  +call_server(ServerName, Msg, Timeout) ->
   	%%修改第三个参数Timeout 为，增加超时时间设置(默认超时时间为5秒)
   	Timeout1 = 20000,
       if Timeout == undefined ->
  -	    gen_server:call(?SERVER, Msg, Timeout1);
  +	    gen_server:call(ServerName, Msg, Timeout1);
          true ->
  -	    gen_server:call(?SERVER, Msg, Timeout1)
  +	    gen_server:call(ServerName, Msg, Timeout1)
       end.
   
   add_conn(Conn, State) ->
  
positive.code: %%
  %% @spec transaction(PoolId::atom(), Fun::function()) ->
  %%   {atomic, Result} | {aborted, {Reason, {rollback_result, Result}}}
  transaction(PoolId, Fun) ->
      transaction(PoolId, Fun, undefined).
  
  transaction(PoolId, Fun, Timeout) ->
      case get(?STATE_VAR) of
  	undefined ->
  	    call_server({transaction, PoolId, Fun}, Timeout);
  	State ->
  	    case mysql_conn:get_pool_id(State) of
  		PoolId ->
  
negative.code: 			Other -> {atomic, Other}
  		    end;
  		_Other ->
  		    call_server(ServerName, {transaction, PoolId, Fun}, Timeout)
  	    end
      end.
  
  