Create an EMR function

This topic describes how to create an E-MapReduce (EMR) function.

1. Go to the DataStudio page.
   1. Log on to the DataWorks console.
   2. In the left-side navigation pane, click Workspaces.
   3. In the top navigation bar, select the region where your workspace resides, find the workspace, and then click Data Analytics in the Actions column.
2. Create a workflow. For more information, see Create a workflow.
3. Write Java code in an offline Java environment, compress the code to a JAR package, and then upload the package as a JAR resource to DataWorks. For more information, see Create and use an EMR JAR resource.
4. Create a function.
   1. Click the workflow in the Business Flow section, right-click EMR, and then choose Create > Function.
   2. In the Create Function dialog box, set the Function Name, Engine Instance, and Location parameters.
   3. Click Create.
   4. In the Function information section of the configuration tab that appears, set the parameters.
      

      Parameter	Description
      Function Type	The type of the function. Valid values: Mathematical Operation Functions, Aggregate Functions, String Processing Functions, Date Functions, Window Functions, and Other Functions.
      Engine Instance	The EMR cluster that is associated with the current workspace. By default, you cannot change the engine instance.
      Engine Type	The type of the compute engine. By default, you cannot change the engine type.
      EMR database	The database where the EMR cluster resides. Select a database from the drop-down list. To create a database, click New Library. In the New Library dialog box, set the parameters and click OK.
      Function Name	The name of the function. You can use this name to reference the function in SQL statements. The function name must be globally unique and cannot be changed after the function is created.
      Owner	This parameter is automatically set.
      Class Name	Required. The name of the class that implements the function.
      Resource	Required. The resource to be used in the function. Select a resource from the ones that are created in the current workspace from the drop-down list. To create a resource, click Create Resource. In the Create Resource dialog box, set the parameters and click Create.
      Description	The description of the function.
      Expression Syntax	The syntax of the function. Example: test.
      Parameter Description	The description of the input and output parameters that are supported.
      Return Value	Optional. The return value. Example: 1.
      Example	Optional. The example of the function.

5. Click the icon in the top toolbar.
6. Commit the function.
   1. Click the icon in the top toolbar.
      Note You must select a resource group for scheduling when you commit the EMR function. We recommend that you use an exclusive resource group for scheduling. If no exclusive resource groups for scheduling are available, you can purchase and configure one. For more information, see Create and use an exclusive resource group for scheduling.
   2. In the Commit Node dialog box, enter your comments in the Change description field.
   3. Click OK.
7. Commit the function.
   1. Click the icon in the top toolbar.
   2. In the Commit Node dialog box, enter your comments in the Change description field.
   3. Click OK.