A split schema is very much necessary for implementing High Availability. Per my understanding, execution of DB scripts alone will not require any downtime. Downtime will be required for application restarts and that is handled well by the rolling restarts. During the rolling restart, users are moved from Pega 7 Platform servers using the old rules schema to Pega 7 Platform servers using the new rules schema.
Does Pega provide any option to handle DB changes (DB change Script execution) while deploying changes to the production using high availability as both old and new rules schema point to same data schema (as making change in Data schema will be available to Old schema (Current production) users as well)? and this might cause errors on current users screen.
There application downtime is mandatory when you have a DB change?