We are now working on making a new SAPUI5 List Report APP, the objective is to let users to run a CDS View report on this SAPUI5 List Report APP, and download the data as MS Excel file.
When we finished the development and started the test, we have found that the "export Excel" speed is not fast enough with our users' expectation.
And based on some rough search on the documents, we have found that we can set the Export Excel to either generating them from the "frontend" or "backend" by changing the "exportType" value between "UI5Client" and "GW", we were expecting loading from "backend" (GW) should be faster than "frontend" (UI5Client), but the test result shown that loading the Excel file from "frontend" is in fact faster than "backend".
So the questions we would like to know are:
1. Based on the SAP design, which ("frontend" or "backend") should be generating the Excel file faster?
2. Isn't that "backend" should be faster because the data is generated directly inside the server, compared to multiple "batch calls" when we use "frontend"?
3. If the performance varies between different conditions, please kindly advise in which situation "frontend" is faster? In which situation "backend" is faster?