S/4HANA Fiori Overview Pages provide important analytical insights about transaction data, but they can not stand on the way of transaction data changes. In some cases Fiori Overview Page application might occupy multiple application server processes and put heavy load on HANA DB, causing system performance issues. In my blog I explain how to prevent that.
Typical Fiori Overview Page has a number of cards.

Usually one OData service populates all cards. HTTP requests for all these cards are batched into one request, but SAP Gateway, by default, process them in parallel at back-end. Parallel processing means consumption as many dialog process as there are Overview Page cards or available system dialog processes (the least of two).

If Overview Page is used often and simultaneously by number of user then system might run out application server processes and spike HANA DB utilization. To prevent that you might need to switch off Parallelization of Batch Requests.
To do that you need to need to open OData service in Maintain Service transaction /IWBEP/REG_SERVICE, then click Display

On next screen click on Configure button

And finally check Deactivate Parallelization of Batch Requests checkbox

After the change batched requests are executed sequentially occupying only one process .

Voilà
See my book
SAP S/4HANA Analytical Applications with Fiori Elements for more Fiori Elements tips and tricks