03-deduplication

To prevent duplicate source key errors in a Delta Lake MERGE, apply a deduplication pattern that orders source data by timestamp descending and drops duplicates on the business key before merging.

A Gold layer MERGE fails with a multiple source row matching error because the Silver table contains duplicate business keys from incremental streaming or CDC, requiring source deduplication before the MERGE.

The best way to deduplicate Silver table records is to order the data by timestamp descending and then drop duplicates on the business key, ensuring only the latest record merges into the Gold layer.

Handle duplicate business keys from CDC or SCD Type 2 by applying a standardized deduplication pattern that sorts by timestamp descending and removes duplicates before performing the Delta MERGE.

Yes, this deduplication pattern works for incremental DLT streaming data by ordering records by timestamp descending and dropping duplicates on the business key to ensure source uniqueness before merging.

You need to deduplicate source data before a Delta MERGE when Silver tables contain multiple records for the same business key due to streaming, CDC, SCD Type 2, or multiple batch loads.