Exam DP-700 topic 1 question 28 discussion

Optimise!

In Delta Lake, the OPTIMIZE command is used to consolidate small Parquet files into larger ones. This improves query performance by reducing the overhead of managing many small files. VACUUM command is used to clean up and remove files that are no longer needed (e.g., old versions of data files, deleted files)

Optimize solves the "small file problem" by consolidating multiple small files into larger parquet files

Optimize: Consolidates multiple small Parquet files into large file. Big Data processing engines, and all Fabric engines, benefit from having larger files sizes. Having files of size above 128 MB, and optimally close to 1 GB, improves compression and data distribution, across the cluster nodes. It reduces the need to scan numerous small files for efficient read operations. It's a general best practice to run optimization strategies after loading large tables.

Link: https://learn.microsoft.com/en-us/fabric/data-engineering/lakehouse-table-maintenance

To consolidate the underlying Parquet files in Table1, you should run the OPTIMIZE command.