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tFileOutputDelimited MapReduce properties (deprecated)

Availability-noteDeprecated

These properties are used to configure tFileOutputDelimited running in the MapReduce Job framework.

The MapReduce tFileOutputDelimited component belongs to the MapReduce family.

The component in this framework is available in all Talend products with Big Data and Talend Data Fabric.

Availability-noteDeprecated
The MapReduce framework is deprecated from Talend 7.3 onwards. Use Talend Jobs for Apache Spark to accomplish your integration tasks.

Basic settings

Property type

Either Built-In or Repository.

 

Built-In: No property data stored centrally.

 

Repository: Select the repository file where the properties are stored.

The properties are stored centrally under the Hadoop Cluster node of the Repository tree.

The fields that come after are pre-filled in using the fetched data.

For further information about the Hadoop Cluster node, see the Getting Started Guide.

Click this icon to open a database connection wizard and store the database connection parameters you set in the component Basic settings view.

For more information about setting up and storing database connection parameters, see Talend Studio User Guide.

Schema and Edit Schema

A schema is a row description. It defines the number of fields (columns) to be processed and passed on to the next component. When you create a Spark Job, avoid the reserved word line when naming the fields.

Click Edit schema to make changes to the schema. If the current schema is of the Repository type, three options are available:

  • View schema: choose this option to view the schema only.

  • Change to built-in property: choose this option to change the schema to Built-in for local changes.

  • Update repository connection: choose this option to change the schema stored in the repository and decide whether to propagate the changes to all the Jobs upon completion. If you just want to propagate the changes to the current Job, you can select No upon completion and choose this schema metadata again in the Repository Content window.

 

Built-In: You create and store the schema locally for this component only.

 

Repository: You have already created the schema and stored it in the Repository. You can reuse it in various projects and Job designs.

Folder

Browse to, or enter the path pointing to the data to be used in the file system.

This path must point to a folder rather than a file, because a Talend Map/Reduce Job need to write in its target folder not only the final result but also multiple part- files generated in performing Map/Reduce computations.

Note that you need to ensure you have properly configured the connection to the Hadoop distribution to be used in the Hadoop configuration tab in the Run view.

Action

Select an operation for writing data:

Create: Creates a file and write data in it.

Overwrite: Overwrites the file existing in the directory specified in the Folder field.

Row separator

The separator used to identify the end of a row.

Field separator

Enter a character, a string, or a regular expression to separate fields for the transferred data.

Include Header

Select this check box to include the column header to the file.

Custom encoding

You may encounter encoding issues when you process the stored data. In that situation, select this check box to display the Encoding list.

Select the encoding from the list or select Custom and define it manually. This field is compulsory for database data handling. The supported encodings depend on the JVM that you are using. For more information, see https://docs.oracle.com.

Compress the data

Select the Compress the data check box to compress the output data.

Hadoop provides different compression formats that help reduce the space needed for storing files and speed up data transfer. When reading a compressed file, the Studio needs to uncompress it before being able to feed it to the input flow.

Merge result to single file

Select this check box to merge the final part files into a single file and put that file in a specified directory.

Once selecting it, you need to enter the path to, or browse to the folder you want to store the merged file in. This directory is automatically created if it does not exist.

The following check boxes are used to manage the source and the target files:
  • Remove source dir: select this check box to remove the source files after the merge.

  • Override target file: select this check box to override the file already existing in the target location. This option does not override the folder.

If this component is writing merged files with a Databricks cluster, add the following parameter to the Spark configuration console of your cluster:
spark.sql.sources.commitProtocolClass org.apache.spark.sql.execution.datasources.SQLHadoopMapReduceCommitProtocol
This parameter prevents the merge file including the log file automatically generated by the DBIO service of Databricks.

This option is not available for a Sequence file.

Advanced settings

Advanced separator (for number)

Select this check box to change the separator used for numbers. By default, the thousands separator is a comma (,) and the decimal separator is a period (.).

This option is not available for a Sequence file.

CSV options

Select this check box to include CSV specific parameters such as Escape char and Text enclosure.
Information noteImportant: With Spark version 2.0 and onward, special characters must be escaped, that is "\\" and "\"" instead of "\" and """.
Use local timezone for date Select this check box to use the local date of the machine in which your Job is executed. If leaving this check box clear, UTC is automatically used to format the Date-type data.

Global Variables

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.

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

Usage rule

In a Talend Map/Reduce Job, it is used as an end component and requires a transformation component as input link. The other components used along with it must be Map/Reduce components, too. They generate native Map/Reduce code that can be executed directly in Hadoop.

Once a Map/Reduce Job is opened in the workspace, tFileOutputDelimited as well as the MapReduce family appears in the Palette of the Studio.

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.

Hadoop Connection

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.

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