Run Table Migration

Migrating tables from Synapse to Fabric

The display on the right side of the screen shows just how quickly the Full Table Copy is progressing and indicates when the migration is complete.

When complete, the Overview tab shows that the Source and Target are connected.

Select the Tables tab to view the list of Table names and their corresponding Target names.

Choosing between Polybase and SQL Select

Polybase Mode: minimizes load on your migration server while maximizing throughput.

• Omni Loader orchestrates the process with minimal resource usage.

• Synapse exports tables as Parquet files to ADL storage.

• Fabric Warehouse ingests the Parquet files.

SQL Select Mode: allows direct control for better monitoring and troubleshooting.

• Progress bars show real-time migration status.

• Omni Loader handles data reading, compression, and upload.

• More reliable error handling and recovery.

You can improve performance according to dataset size and configuration.

In Polybase mode, using a lightweight VM is fine (Omni Loader just orchestrates).

In SQL Select mode, use a larger VM (8-32 vCPUs depending on the data volume). More CPU = faster compression and network throughput.

For huge schemas (10,000+ tables) use precompute scripts to speed up schema loading.

Run errors in Polybase

In Polybase mode, results can appear before Parquet files have been completely written. This may result in an Error report. Simply return to the Overview and click Load tables again. Typically, such issues go away.

If an error persists, you can examine the affected table by clicking the table name in the Overview tab and examining the table in the Output tab.

Polybase mode will replace any empty datasets with a NULL. This may trigger a run error.

If, however, your project is generated using SQL Select mode, Omni Loader does all the work. This gives you detailed controls to help eliminate run errors.