In Delta Lake, a shallow clone creates a new table by copying the metadata of the source table without duplicating the data files. When thevacuumcommand is run on the source table, it removes old data files that are no longer needed to maintain the transactional log's integrity, potentially including files referenced by the shallow clone's metadata. If these files are purged, the shallow cloned tables will reference non-existent data files, causing them to stop working properly. This highlights the dependency of shallow clones on the source table's data files and the impact of data management operations likevacuumon these clones.References: Databricks documentation on Delta Lake, particularly the sections on cloning tables (shallow and deep cloning) and data retention with thevacuumcommand (https://docs.databricks.com/delta/index.html ).