API-Method seem to be very slow

I just want to get all the data of a row, by mouseenter on special cells, for saving it in an array for easy access.
But this takes about 2,5 seconds, what is too much for opening popups with detailed informations.

Am I doing something wrong ?

    $('#'+tabellenname+' tbody .showTooltip').on('mouseenter', function(event)
    {
        // Daten der Zelle, Zeile und Spalte auslesen
        var columnIndex =   tableApi.cell( this ).index().column;
        var rowIndex =  tableApi.cell( this ).index().row;
        var spalte =        $(tableApi.column( columnIndex ).header()).text();
        var data = new Array();

        for(var index = 0; index < spaltenArray[tabellenname].length; index++)
        {
            var title = spaltenArray[tabellenname][index];
            if(tableApi.row(rowIndex).data() !== undefined)
            {
                data[title] = tableApi.row(rowIndex).data()[index];
            }
        }
    });