I am trying to use slots to run my queries, so I asked from BigQuery to increase my quota after my request got approval (5 days!) I pressed on "buy slots" and select 400 (i have 500 available) and I thought that will be enough to make sure that my queries will run on those 400 slots and not on the "on-demand-serverless" method. unfortunately, I got the bill for my queries the day after and I saw they charged me for the "on-demand" charging method. I tried to use BigQuery chat support to understand how to use those 400 slots and guarantee that my queries will run on those slots but I didn't get any useful answer!
does someone know how can I use those slots to run my query? what I did wrong? thanks,