How To Download Csv From Databricks

Downloading CSV Files from Databricks

There are several methods to download CSV files from Databricks, each with its own advantages and limitations.

Method 1: Using Databricks Notebook

This method involves using a Databricks Notebook to read the CSV file from DBFS and create a downloadable link. Here’s how you can do it:

1. Open a Databricks Notebook and set the language to Python.
2. Read the CSV file into a Spark DataFrame using spark.read.csv("dbfs:/FileStore/data.csv", header=True, inferSchema=True).
3. Convert the Spark DataFrame to a Pandas DataFrame with df.toPandas().
4. Create a downloadable link by encoding the CSV data in base64 format and rendering it as an HTML anchor tag.
5. Run the cell and click the generated link to download the CSV file.

Method 2: Using Databricks CLI

This method involves using the Databricks command-line interface (CLI) to copy the CSV file from DBFS to your local machine.

1. Install the Databricks CLI using pip install databricks-cli.
2. Authenticate with your Databricks workspace using a personal access token.
3. Use the command databricks fs cp dbfs:/path/to/file.csv local/path/to/file.csv to download the CSV file.

Method 3: Direct Download from Query Results

For small datasets, you can directly download query results as a CSV file from the Databricks UI.

1. Run your query in the Databricks UI.
2. Look for the download button or icon in the results pane.
3. Choose “CSV” as the export format and save the file.

Frequently Asked Questions

FAQs

• Q: What is the maximum number of rows that can be downloaded using the Notebook method?

  A: The Notebook method is generally limited to datasets with less than 1 million rows due to performance constraints.

• Q: How do I handle large datasets with more than 1 million rows?

  A: For larger datasets, consider exporting them to DBFS and then downloading them using the Databricks CLI.

• Q: Can I use external tools to download CSV files from Databricks?

  A: Yes, you can use external client tools like Visual Studio Code with the Databricks extension or standalone DBFS Explorer tools to download CSV files.

• Q: How do I ensure I have the correct permissions to access DBFS files?

  A: Make sure you have the necessary permissions set up in your Databricks workspace to access files in DBFS.

• Q: Can I export data directly to Excel from Databricks?

  A: While Databricks does not support direct export to Excel, you can export data as a CSV file and then import it into Excel.

• Q: How do I authenticate with the Databricks CLI?

  A: You need to use a personal access token to authenticate with the Databricks CLI. This involves running databricks configure --token and entering your workspace URL and token.

• Q: What if I encounter issues with the downloadable link generated in the Notebook?

  A: Ensure that your internet connection is stable and that you have correctly encoded the CSV data in base64 format.

Bottom Line

Downloading CSV files from Databricks can be achieved through various methods, each suited to different scenarios. Whether you prefer using the Databricks Notebook for interactive downloads, the CLI for command-line efficiency, or direct download from query results, there’s a method that fits your needs.

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