Mirroring SQL Server - New tables added via Fabric REST API cause full mirroring of all tables

Hi Lukas_K ,

This behavior—where all tables are mirrored after an updateDefinition call—is a known issue. When new tables are added via the REST API, the UI reflects mirroring for all available tables, even if only a subset was specified 

This does not happen when tables are added manually via the UI, suggesting a discrepancy between the API's behavior and the UI logic.
1.Ensure your API calls include the preview=true parameter to avoid unintended behavior due to response format changes
2.Validate whether your integration is parsing the response correctly. If it expects an array but receives a JSON object with a value property, it might misinterpret the payload.
3.Until the API behavior is stabilized, consider using the UI for adding tables to avoid triggering full mirroring.

Additionally, you might want to check out-

Troubleshoot Fabric mirrored databases

Hope this helps!

If the response has addressed your query, please accept it as a solution  so that other members can easily find it.
Thank you.