I've created an interactive grid report using a complex sql query.
This is a very fine-tuned SQL query. And loads Millions of data in 2-3 seconds on apex as well. But usually filtered record count will be between 150k - 300k.
When it comes to download the data, when clicked on download button, there was a delay of 2-3 mins till the download gets started.
Between this period there is no update in console or network as well.
Initially I though at click on download it may have to process data again. And thus, I've created a temporary table in which I stored the data and then get it into IG. I thought it could speed up the process since it has to get data from single table only. But no use. It still taking time to start downloading process.
So, is there any way to quickly start this process? Or at least any way to add a spinner when clicked on downlaod?