PowerShell Scripting to Replicate Databricks Data to MySQL

The CData Cmdlets for Databricks offer live access to Databricks data from within PowerShell. Using PowerShell scripts, you can easily automate regular tasks like data replication. This article will walk through using the CData Cmdlets for Databricks and the CData Cmdlets for MySQL in PowerShell to replicate Databricks data to a MySQL database.

Getting Started

---

After obtaining the needed connection properties, accessing Databricks data in PowerShell and preparing for replication consists of four basic steps.

To connect to a Databricks cluster, set the properties as described below.

Note: The needed values can be found in your Databricks instance by navigating to Clusters, and selecting the desired cluster, and selecting the JDBC/ODBC tab under Advanced Options.

• Server: Set to the Server Hostname of your Databricks cluster.
• HTTPPath: Set to the HTTP Path of your Databricks cluster.
• Token: Set to your personal access token (this value can be obtained by navigating to the User Settings page of your Databricks instance and selecting the Access Tokens tab).

Collecting Databricks Data

1. Install the module:

   Install-Module DatabricksCmdlets

2. Connect to Databricks:

    $databricks = Connect-Databricks -Server $Server -Port $Port -TransportMode $TransportMode -HTTPPath $HTTPPath -UseSSL $UseSSL -User $User -Password $Password
    

3. Retrieve the data from a specific resource:

    $data = Select-Databricks -Connection $databricks -Table "Customers"
    

   You can also use the Invoke-Databricks cmdlet to execute pure SQL-92 statements:

    $data = Invoke-Databricks -Connection $databricks -Query 'SELECT * FROM Customers WHERE Country = @Country' -Params @{'@Country'='US'}
    

4. Save a list of the column names from the returned data.

    $columns = ($data | Get-Member -MemberType NoteProperty | Select-Object -Property Name).Name
    

Inserting Databricks Data into the MySQL Database

With the data and column names collected, you are ready to replicate the data into a MySQL database.

1. Install the module:

   Install-Module MySQLCmdlets

2. Connect to MySQL, using the server address and port of the MySQL server, valid user credentials, and a specific database with the table in which the data will be replicated:

    $mysql = Connect-MySQL -User $User -Password $Password -Database $Database -Server $Server -Port $Port
    

3. Loop through the Databricks data, store the values, and use the Add-MySQL cmdlet to insert the data into the MySQL database, one row at a time. In this example, the table will need to have the same name as the Databricks resource (Customers) and to exist in the database.

    $data | % {
    $row = $_
    $values = @()
    $columns | % {
    $col = $_
    $values += $row.$($col)
    }
    Add-MySQL -Connection $mysql -Table "Customers" -Columns $columns -Values $values
    }
    

You have now replicated your Databricks data to a MySQL database. This gives you freedom to work with Databricks data in the same way that you work with other MySQL tables, whether that is performing analytics, building reports, or other business functions.

Notes

• Once you have connected to Databricks and MySQL in PowerShell, you can pipe command results to perform the replication in a single line:

   Select-Databricks -Connection $databricks -Table "Customers" | % {
   $row = $_
   $values = @()
   $columns | % {
   $col = $_
   $values += $row.$($col)
   }
   Add-MySQL -Connection $mysql -Table "Customers" -Columns $columns -Values $values
   }
   

• If you wish to replicate the Databricks data to another database using another PowerShell module, you will want to exclude the Columns, Connection, and Table columns from the data returned by the Select-Databricks cmdlet since those columns are used to help pipe data from one CData cmdlet to another:

   $columns = ($data | Get-Member -MemberType NoteProperty | Select-Object -Property Name).Name | ? {$_ -NotIn @('Columns','Connection','Table')}