A colleague implemented a hybrid system for a SaaS product he was leading. Normally the product is a single app, single database with column as a tenant ID disc

A colleague implemented a hybrid system for a SaaS product he was leading. Normally the product is a single app, single database with column as a tenant ID discriminator, but for specific tenants he built in an option to specify a separate database. This allowed all tenants that wanted higher performance or data saved in a separate location to be able to buy in, while most of the tenants were in a multitenant database. Solution I implemented on my project (IoT) was shared apps, shared database. When we were starting the project, we decided to use a column as a discriminator and designed the system so that developers for entities that need to be tenant specific, just need to extend an abstract class, the rest of the system detects when you are trying to save or load such an entity and in those cases it applies a filter or automatically assigns the tenant ID. This means that normal developer can work just like he would on a single tenant application. I feel this is pretty normal stuff.