Why is fetching data so slow?

[Master_T]

Hello

I'm trying to develop a custom visual that needs a lot of data (about 500k rows).

I know from the documentation that fetching data from PowerBI is limited to 30k rows, but you can fetch more with a call to the fetchMoreData() api.

That approach works, but it's extremely slow. In my tests, every call to fetchMoreData(), which retrieves 30k rows of data at a time, takes 15-20 seconds for a table with 10 columns.... is such low performance normal? Or do you think there's something wrong on my end?

[Master_T]

I've done some additional tests, and the thing that is even weirder is that the time required to fetch the next batch of rows using the fetchModerData() api seems completely unrelated to the amount of data that is retrieved. I've tried to set the dataViaMapping's window size to 3000 instead of 30000, and every fetch requires exactly the same time: about 20 seconds.

What is going on here? Is this an artificial limit imposed by PowerBI? Why is fetching data so absurdly slow??