Hi All, i suffered the export module(https://marketplace.mendix.com/link/component/726) performance issue for many days, here i record the investigation and solutions base on my fixing. hope this topic will help others to save the investigation time. 2 performance issue found at least: 1st: the excel export module used single thread to export data, which is really slow if big data need to be exported. fixing: using muti-thread to handle the data(but be careful on creating excel rows, you need to use lock for creating row method) 2nd: the module used POI to write excel data, for setting sheet preference, POI interface sheet.autoSizeColumn will check all cells to get proper width, this line is very costly. workaround: using the cell values to calculate the proper width and then directly use sheet.setColumnWidth method instead.