Hmmm, the question is syncing data between two database. I don’t think this is a problem to be solved exclusively with elixir. Considering you only have read only access to SQL server, tools like Debezium (https://debezium.io/) which Change Data Capture probably wouldn’t work (if you could use Debezium, you could capture data from SQL server and write it to PostgresDB).
In the past, what i have done is making a data pump (which is inspired by Ingest data from a relational database | Elastic Docs) which periodically read from source DB (SQL Server) (limited by last updated_at/inserted_at), and write the data to sink DB (PostgreSQL in this case).
