What mirroring creates in Fabric: an almost real-time replica of a database held elsewhere, stored in OneLake as Delta tables. Users can query it with T-SQL through the read-only SQL analytics endpoint that comes with it.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains Mirrored database in context, with comparison tables and the common traps.
Terms in this definition
- Mirroring
A way of keeping a copy of an outside database, for example Azure SQL Database, Cosmos DB or Snowflake, continuously up to date in OneLake as Delta tables inside a mirrored database. You query it in T-SQL via its SQL analytics endpoint, and the replication compute costs nothing.
- Azure AI Search replica
Additional copy of a search service's engine and indexes. Replicas spread queries for load balancing and improve availability, so adding them is the fix when queries are throttled with HTTP 503.
- Schema
The middle part of a Unity Catalog name (
catalog.schema.table), grouping tables, views, volumes, functions and models inside a catalog. A grant on it covers everything in it now and later, and nothing inside can be reached withoutUSE SCHEMA. - OneLake
Built on Azure Data Lake Storage Gen2, it is the one logical data lake for an entire Microsoft Fabric tenant, provisioned automatically, and the place where every Fabric workload keeps its data.
- T-SQL
The dialect of SQL that Microsoft uses for Azure SQL and SQL Server. Azure Monitor logs are queried with KQL instead.
- SQL analytics endpoint
Read-only SQL access in Fabric to the data in a lakehouse. Power BI using DirectQuery through it performs more slowly than Direct Lake.
Related terms
- Open mirroring
A mirroring approach where an application or third-party tool of any kind uploads its changes as Parquet or delimited text files, plus a _metadata.json file that identifies the keys, to the landing zone of a mirrored database in OneLake. Fabric applies those inserts, updates and deletes to Delta tables on its side.