When you drop an external DELTA table using the SQL Command DROP TABLE table_name, how does it impact metadata (delta log, history), and data stored in the storage?

When you drop an external DELTA table using the SQL Command DROP TABLE table_name, how does it impact metadata (delta log, history), and data stored in the storage?
A . Drops table from metastore, metadata (delta log, history) and data in storage
B. Drops table from metastore, data but keeps metadata (delta log, history) in storage
C. Drops table from metastore, metadata (delta log, history) but keeps the data in storage
D. Drops table from metastore, but keeps metadata (delta log, history) and data in storage
E. Drops table from metastore and data in storage but keeps metadata (delta log, history)

View Answer

Answer: D

Explanation:

The answer is Drops table from metastore, but keeps metadata and data in storage. When an external table is dropped, only the table definition is dropped from metastore everything including data and metadata (Delta transaction log, time travel history) remains in the storage. Delta log is considered as part of metadata because if you drop a column in a delta table (managed or external) the column is not physically removed from the parquet files rather it is recorded in the delta log. The delta log becomes a key metadata layer for a Delta table to work.

Please see the below image to compare the external delta table and managed delta table and how they differ in how they are created and what happens if you drop the table.

Diagram

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