tRunJob in Talend Map/Reduce Jobs - 6.1

Talend Components Reference Guide

EnrichVersion
6.1
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Talend Big Data
Talend Big Data Platform
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Talend Data Integration
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task
Data Governance
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EnrichPlatform
Talend Studio

Warning

The information in this section is only for users that have subscribed to one of the Talend solutions with Big Data and is not applicable to Talend Open Studio for Big Data users.

In a Talend Map/Reduce Job, tRunJob, as well as the other Map/Reduce components preceding it, generates native Map/Reduce code. This section presents the specific properties of tRunJob when it is used in that situation. For further information about a Talend Map/Reduce Job, see Talend Big Data Getting Started Guide.

Component family

System

 

Basic settings 

Use dynamic job

Select this check box to allow multiple Jobs to be called and processed. When this option is enabled, only the latest version of the Jobs can be called and processed. An independent process will be used to run the subjob. The Context and the Use an independent process to run subjob options disappear.

Warning

The Use dynamic job option is not compatible with the Jobserver cache. Therefore, the execution may fail if you run a Job that contains tRunjob with this check box selected in Talend Administration Center.

Warning

This option is incompatible with the Use or register a shared DB Connection option of database connection components. When tRunJob works together with a database connection component, enabling both options will cause your Job to fail.

 

Context job

This field is visible only when the Use dynamic job option is selected. Enter the name of the Job that you want to call from the list of Jobs selected.

 

Job

Select the Job to be called in and processed. Make sure you already executed once the Job called, beforehand, in order to ensure a smooth run through tRunJob.

 

Version

Select the child Job version that you want to use.

 

Context

If you defined contexts and variables for the Job to be run by the tRunJob, select the applicable context entry on the list.

 

Die on child error

Clear this check box to execute the parent Job even though there is an error when executing the child Job.

 

Transmit whole context

Select this check box to get all the context variables from the parent Job. Deselect it to get all the context variables from the child Job.

If this check box is selected when the parent and child Jobs have the same context variables defined:

  • variable values for the parent Job will be used during the child Job execution if no relevant values are defined in the Context Param table.

  • otherwise, values defined in the Context Param table will be used during the child Job execution.

 

Context Param

You can change the value of selected context parameters. Click the [+] button to add the parameters defined in the Context tab of the child Job. For more information on context parameters, see Talend Studio User Guide.

The values defined here will be used during the child Job execution even if Transmit whole context is selected.

Advanced settings

Print Parameters

Select this check box to display the internal and external parameters in the Console.

Global Variables

ERROR_MESSAGE: the error message generated by the component when an error occurs. This is an After variable and it returns a string. This variable functions only if the Die on error check box is cleared, if the component has this check box.

CHILD_RETURN_CODE: the return code of a child Job. This is an After variable and it returns an integer.

CHILD_EXCEPTION_STACKTRACE: the exception stack trace from a child Job. This is an After variable and it returns a string.

A Flow variable functions during the execution of a component while an After variable functions after the execution of the component.

To fill up a field or expression with a variable, press Ctrl + Space to access the variable list and choose the variable to use from it.

For further information about variables, see Talend Studio User Guide.

Usage in Map/Reduce Jobs

In a Talend Map/Reduce Job, this component is used standalone. It generates native Map/Reduce code that can be executed directly in Hadoop.

You need to use the Hadoop Configuration tab in the Run view to define the connection to a given Hadoop distribution for the whole Job.

This connection is effective on a per-Job basis.

For further information about a Talend Map/Reduce Job, see the sections describing how to create, convert and configure a Talend Map/Reduce Job of the Talend Big Data Getting Started Guide.

Note that in this documentation, unless otherwise explicitly stated, a scenario presents only Standard Jobs, that is to say traditional Talend data integration Jobs, and non Map/Reduce Jobs.

Limitation

The Use dynamic job option of tRunJob allows the main Job to call the child Job dynamically at runtime. However, this option does not work if the child Job had been exported with the Axis WebService (WAR) type, and been deployed to Tomcat as a web service.

For an alternative solution, see https://help.talend.com/pages/viewpage.action?pageId=27029205 for details.