Which file format is used for raw data loaded into OneLake according to the Delta Lake specifications?

Which file format is used for raw data loaded into OneLake according to the Delta Lake specifications?

• A. JSON
• B. Parquet
• C. CSV
• D. XML

Answer: (B)

Parquet is the file format used for raw data loaded into OneLake under Delta Lake specifications. Parquet is a columnar storage format, which means it stores data by columns rather than rows, enabling fast analytics through column pruning and predicate pushdown and delivering strong compression. Delta Lake keeps its actual data as Parquet files and uses a transaction log to track these files, providing ACID transactions, schema evolution, and time travel. Formats like JSON, CSV, and XML are text-based and row-oriented, making large-scale analytics slower and less storage-efficient, and they don’t align with how Delta Lake manages data files, so Parquet is the standard choice.

Parquet is the file format used for raw data loaded into OneLake under Delta Lake specifications. Parquet is a columnar storage format, which means it stores data by columns rather than rows, enabling fast analytics through column pruning and predicate pushdown and delivering strong compression. Delta Lake keeps its actual data as Parquet files and uses a transaction log to track these files, providing ACID transactions, schema evolution, and time travel. Formats like JSON, CSV, and XML are text-based and row-oriented, making large-scale analytics slower and less storage-efficient, and they don’t align with how Delta Lake manages data files, so Parquet is the standard choice.