Multiple schema best practice clarification

Question

docs.appian.com/.../appian-cloud-database-administration.html 
 Does anyone have additional context on the reasoning behind these recommendations? My client has hard data segregation needs and plans to use multiple schemas to address them, but we want to know more about what problems we might expect to run into. We're using the cloud database. 
 The biggest issue reported to me so far had to do was a problem around using compare and deploy to update stored procedures (ones that reference multiple schemas), but they found a manual workaround to mitigate that issue. I'm curious if there's any other notable issues that can be expected or if there's any loss of other capabilities we're unaware of at this time. 
 Thanks

Shubham Aware · Answer

Additional issues include complexity in cross-schema joins causing permission and performance problems, intermittent stored procedure failures, sync limits with large data volumes, and limited direct SQL operations in the cloud. Best to keep most data in one schema unless strict segregation is needed and test carefully.

Stefan Helzle · Answer

I think that data segregation does not mean you HAVE to use separate databases/schemas. Security in Appian is mostly configured inside Appian, but not the database.

Harsha Sharma · Answer

Different database/schemas can make the establishing relationships difficult between two dependent tables residing in different schemas. In practice we do use different schemas for different applications on a server for better segregation and organisation. Yet for one application all tables, functions, procedures etc are easier to work with when they share the same database.