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Replicate HDFS Data from PowerShell


Write a quick PowerShell script to query HDFS data. Use connectivity to the live data to replicate HDFS data to SQL Server.



The CData ODBC Driver for HDFS enables out-of-the-box integration with Microsoft's built-in support for ODBC. The ODBC driver instantly integrates connectivity to the real HDFS data with PowerShell.

You can use the .NET Framework Provider for ODBC built into PowerShell to quickly automate integration tasks like replicating HDFS data to other databases. This article shows how to replicate HDFS data to SQL Server in 5 lines of code.

You can also write PowerShell code to download HDFS data. See the examples below.

Create an ODBC Data Source for HDFS

If you have not already, first specify connection properties in an ODBC DSN (data source name). This is the last step of the driver installation. You can use the Microsoft ODBC Data Source Administrator to create and configure ODBC DSNs.

In order to authenticate, set the following connection properties:

  • Host: Set this value to the host of your HDFS installation.
  • Port: Set this value to the port of your HDFS installation. Default port: 50070

Connect to HDFS

The code below shows how to use the DSN to initialize the connection to HDFS data in PowerShell:

$conn = New-Object System.Data.Odbc.OdbcConnection $conn.ConnectionString = "DSN=CData HDFS Source x64"

Back Up HDFS Data to SQL Server

After you enable caching, you can use the code below to replicate data to SQL Server.

Set the following connection properties to configure the caching database:

  • CacheProvider: The name of the ADO.NET provider. This can be found in the Machine.config for your version of .NET. For example, to configure SQL Server, enter System.Data.SqlClient.

  • CacheConnection: The connection string of properties required to connect to the database. Below is an example for SQL Server:

    Server=localhost;Database=RSB;User Id=sqltest;Password=sqltest;

The SQL query in the example can be used to refresh the entire cached table, including its schema. Any already existing cache is deleted.

$conn.Open() # Create and execute the SQL Query $SQL = "CACHE DROP EXISTING SELECT * FROM " + $Files $cmd = New-Object System.Data.Odbc.OdbcCommand($sql,$conn) $count = $cmd.ExecuteNonQuery() $conn.Close()

The driver gives you complete control over the caching functionality. See the help documentation for more caching commands and usage examples. See the help documentation for steps to replicate to other databases.

Other Operations

To retrieve HDFS data in PowerShell, call the Fill method of the OdbcDataAdapter method. To execute data manipulation commands, initialize the OdbcCommand object and then call ExecuteNonQuery. Below are some more examples commands to HDFS through the .NET Framework Provider for ODBC:

Retrieve HDFS Data

$sql="SELECT FileId, ChildrenNum from Files" $da= New-Object System.Data.Odbc.OdbcDataAdapter($sql, $conn) $dt= New-Object System.Data.DataTable $da.Fill($dt) $dt.Rows | foreach { $dt.Columns | foreach ($col in dt{ Write-Host $1[$_] } }

Ready to get started?

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HDFS Icon HDFS ODBC Driver

The HDFS ODBC Driver is a powerful tool that allows you to connect with live data from HDFS, directly from any applications that support ODBC connectivity.

Access HDFS data like you would a database - read, write, and update HDFS HDFSData, etc. through a standard ODBC Driver interface.

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