Answer-first summary for fast verification
Answer: It will optimize query performance by filtering relevant partitions without scanning the entire dataset.
The PARTITION BY clause when unloading Snowflake data to Parquet organizes the output into directory-based partitions based on the specified expression. This enables partition pruning, where downstream query engines (including Snowflake external tables) can scan only the relevant subset of files rather than reading the entire dataset. This directly optimizes query performance by reducing the amount of data scanned. While Parquet does provide compression (option C), this is an inherent feature of the Parquet format itself, not something enabled by the PARTITION BY clause. Options A and B describe encryption and data integrity mechanisms that are not the primary purpose of partitioning.
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When unloading data from Snowflake to the Parquet file format, what is the purpose of using the PARTITION BY clause?
A
It will provide a mechanism to encrypt each micro-partition with a unique key.
B
It will guarantee data integrity by splitting the data into smaller, manageable chunks.
C
It will increase storage efficiency by automatically compressing data based on access patterns.
D
It will optimize query performance by filtering relevant partitions without scanning the entire dataset.