Databricks-DE-Assoc Troubleshooting, Monitoring, and Optimization Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  DELETE FROM table_name WHERE date < current_date() - 30;

  Why it's wrong here

  This command removes data from the table log and marks it as deleted in the Delta metadata, but it does not physically remove the underlying Parquet files from cloud storage. The storage space remains occupied until a vacuum operation is executed to garbage collect the files.

• ✗

  TRUNCATE TABLE table_name;

  Why it's wrong here

  TRUNCATE removes all data from the table but does not necessarily reclaim the physical storage space in the cloud provider's storage layer immediately. It leaves the underlying directory structure and potentially some data files behind, requiring a vacuum operation to perform final cleanup and reclamation of space.

• ✓

  VACUUM table_name RETAIN 30 DAYS;

  Why this is correct

  VACUUM is the specific command used to delete data files that are no longer part of the Delta table's current state and are older than the specified retention threshold. This operation is necessary to reclaim storage space in cloud object storage and maintain compliance with data management policies.

• ✗

  DROP TABLE table_name;

  Why it's wrong here

  Dropping a table removes the entry from the metastore, but depending on the configuration and storage type, it may not automatically delete the underlying data files in S3 or ADLS. Relying on DROP TABLE for space management is unreliable and does not provide granular control over file retention.