Symptom
You get warning message as "Query not optimized for large quantities of data (N hits); Consider using a query defined on SADL or via the QueryBuilder." Here,N is number of hits.
Environment
SAP Cloud For Customer
SAP Business ByDesign
SAP Cloud Application Studio
Cause
You are getting the warning message because system cannot show all the instances from the system. This is to maintain the performance of the system.A SADL query is a type of query that targets the database directly, and exposes all the required information to the UI. So as do a query for large quantities of data it takes time to fetch the data back from database and display it to the UI and this may decrease the performance of the system and you will observe slowness.
Resolution
You would need to build a SADL query in order to avoid this warning message.
See Also
https://blogs.sap.com/2016/08/01/how-to-create-an-advanced-search-filter-in-custom-owl-screen-using-sadl-query/
Keywords
SADL query ,QueryBuilder, PDI , KBA , AP-RC-BDS-LM , ByDesign Studio Lifecycle Management , Problem