When unloading Snowflake relational data to a Parquet file format, why should the PARTITION BY clause be used?
When unloading Snowflake relational data to a Parquet file format, why should the PARTITION BY clause be used?
https://docs.snowflake.com/en/user-guide/ui-snowsight-activity In Query Profile section, DML Operators, we can see: "Unload Represents a COPY operation that exports data from a table into a file in a stage. Attributes: Location - the name of the stage where the data is saved." Answer is C
Here is the real reply for question 1285: https://www.snowflake.com/guides/what-parquet/#:~:text=Parquet%20is%20an%20open%20source,wide%20variety%20of%20encoding%20types. "Parquet is an open source file format built to handle flat columnar storage data formats. Parquet operates well with complex data in large volumes.It is known for its both performant data compression and its ability to handle a wide variety of encoding types." Based on this I propose C.
By organizing data into partitions during the unload process, subsequent queries can target specific partitions, reducing the amount of data scanned and improving overall query efficiency.
Using the PARTITION BY clause when unloading Snowflake data to Parquet organizes the output into directory‑based partitions based on your chosen expression. This layout enables downstream query engines or Snowflake external tables to prune partitions—scanning only the relevant subset of files—rather than reading every file in the dataset, thereby optimizing query performance without extra cost or complexity.