For those curious, as I was, how this works, beyond the details in the readme and blog post, note that "schema" in this context is both a loose term (we changed the schema, old schema, new schema) AND a concrete thing in PostgreSQL[0]. It's helpful to know that pgroll implements the first one (let's change the schema) using the second one (make Schema objects in PG [1]). The magic is in creating different views in different Schemas that map appropriately to underlying tables (in a third Schema).
Presumably (didn't see this mentioned in the docs yet) the trick is that you re-deploy the app with a new connection string referencing the new schema (as in [3]), while an old app deployment can keep referencing the old schema with its connection string.
Presumably (didn't see this mentioned in the docs yet) the trick is that you re-deploy the app with a new connection string referencing the new schema (as in [3]), while an old app deployment can keep referencing the old schema with its connection string.
Hopefully I got that right.
[0] https://www.postgresql.org/docs/current/ddl-schemas.html [1] https://github.com/xataio/pgroll/blob/main/pkg/roll/execute.... [3] https://stackoverflow.com/a/67525360