Hi , 

In our application , we do have few custom search property for a case type  and dedicated Index for that .

For example , we have added one embedded property say VendorName ( pyWorkPage.Vendor.VendorName) as custom search  property for our work class .  There are few cases present, where we have observed say "Test123" is the value for VendorName property in clipboard .

When I search, "Test123" , in OOTB , case search and trace -->

1. I can see , in background pxRetrieveSearchData activity is getting called , with below parameter ( have given few key parameter alone) :-
   1.  pySearchString:- pyLabel:(Test123)^5 OR (Test123);
   2. pyReportName:-pyWorkSearch;
   3. pyReportClassName:- Work- 
2. pzSearch activity , which internally invoke getSearcherAPI and post that , we are able to see , intended results has been retrieved. 

In pyWorkSearch , Report defination rule ,we can see , Database is selected as Default option for data access which means there is no Elastic  search will be invoked from this RD .We have observed , if we update few OOTB  filter criteria like case Status , then the result is getting updated and pyWorkSearch , RD is having those filter in it .

Can someone pls explain here what exactly PEGA is using in background -- like SQL or Elastic search or Both in this case , to retrieve the result set ?

Note :- We are in PEGA Cloud 8.7.5.