Deleting Parquet Files in Databricks
Deleting Parquet files directly in Databricks is not straightforward because Parquet files themselves do not support direct deletion or updates. However, you can manage data stored in Parquet files by converting them into Delta Lake tables, which provide more flexible data management options.
Method 1: Using Delta Lake Tables
Convert your Parquet files into a Delta Lake table. This allows you to use SQL commands like DELETE to remove data from the table. Delta Lake tables can manage Parquet files efficiently by using features like deletion vectors, which mark rows for deletion without rewriting the entire Parquet file.
Method 2: Manual File Deletion
If you need to delete the Parquet files themselves, you can do so by interacting with the Databricks File System (DBFS) directly. You can use the Databricks CLI, a Databricks Notebook, the Databricks REST API, or the Databricks UI to delete files from DBFS.
Using Databricks CLI for File Deletion
To delete a Parquet file using the Databricks CLI, you can use the following command:
databricks fs rm dbfs:/path/to/your/file.parquet
Frequently Asked Questions
- Q: What are deletion vectors in Delta Lake?
A: Deletion vectors are a feature in Delta Lake that allows marking rows for deletion without rewriting the entire Parquet file. This optimizes storage and improves performance for delete operations.
- Q: Can I directly update Parquet files?
A: No, Parquet files do not support direct updates. You need to read the file, update the data in a DataFrame, and then write it back as a new Parquet file.
- Q: How do I enable deletion vectors in Delta Lake?
A: You can enable deletion vectors by setting the table property
delta.enableDeletionVectors = truewhen creating or altering a Delta table. - Q: What happens to old files after using deletion vectors?
A: Old files with deleted data remain until you run a command like
VACUUMto remove them physically. - Q: Can I use deletion vectors with all Delta clients?
A: No, not all Delta clients support deletion vectors. You need to use compatible versions of Databricks Runtime or Apache Spark.
- Q: How do I delete a folder from DBFS using the UI?
A: Navigate to the DBFS tab in the Databricks UI, locate the folder, right-click it, and select “Delete” from the context menu.
- Q: What is the benefit of using Delta Lake over direct Parquet file management?
A: Delta Lake provides features like ACID transactions, versioning, and efficient data management through SQL commands, making it more suitable for complex data operations.
Bottom Line
Deleting Parquet files in Databricks is best managed by converting them into Delta Lake tables, which offer efficient data management features. For direct file deletion, interacting with DBFS through various methods is necessary.