tImpalaLoad Standard properties

Property type

Either Built-in or Repository.

Built-in: No property data stored centrally.

Repository: Select the repository file in which the properties are stored. The fields that follow are completed automatically using the data retrieved.

Use an existing connection

Select this check box and in the Component List click the relevant connection component to reuse the connection details you already defined.

Distribution

1. Select Import from existing version to import an officially supported distribution as base and then add other required jar files which the base distribution does not provide.

2. Select Import from zip to import the configuration zip for the custom distribution to be used. This zip file should contain the libraries of the different Hadoop elements and the index file of these libraries.

   In Talend Exchange, members of Talend community have shared some ready-for-use configuration zip files which you can download from this Hadoop configuration list and directly use them in your connection accordingly. However, because of the ongoing evolution of the different Hadoop-related projects, you might not be able to find the configuration zip corresponding to your distribution from this list; then it is recommended to use the Import from existing version option to take an existing distribution as base to add the jars required by your distribution.

   Note that custom versions are not officially supported by Talend . Talend and its community provide you with the opportunity to connect to custom versions from the Studio but cannot guarantee that the configuration of whichever version you choose will be easy, due to the wide range of different Hadoop distributions and versions that are available. As such, you should only attempt to set up such a connection if you have sufficient Hadoop experience to handle any issues on your own.

   Information noteNote:

   In this dialog box, the active check box must be kept selected so as to import the jar files pertinent to the connection to be created between the custom distribution and this component.

   For a step-by-step example about how to connect to a custom distribution and share this connection, see .

Version

Select the version of the Hadoop distribution you are using. The available options vary depending on the component you are using.

Impala Driver

Select the driver you are using from the drop-down list.

Host

Database server IP address.

Port

Listening port number of DB server.

Database

Fill this field with the name of the database.

Username

DB user authentication data.

Additional JDBC Settings

Specify additional connection properties for the database connection you are creating.

This option is not available if you have selected the Use an existing connection check box in the Basic settings view.

Use kerberos authentication

This check box is available depending on the Hadoop distribution you are connecting to.

Load action

Select the action you need to carry for writing data into the specified destination.

• When you select LOAD, you are moving or copying data from a directory you specify.

• When you select INSERT, you are moving or copying data based on queries.

Target type

This drop-down list appears only when you have selected INSERT from the Load action list.

Select from this list the type of the location you need to write data in.

• If you select Table as destination, you can still choose to append data to or overwrite the contents in the specified table. This is the only option in the current release.

Action

Select whether you want to OVERWRITE the old data already existing in the destination or only APPEND the new data to the existing one.

Table name

Enter the name of the Hive table you need to write data in.

Note that with the INSERT action, this field is available only when you have selected Table from the Target type list.

File path

Enter the directory you need to read data from.

Query

This field appears when you have selected INSERT from the Load action list.

Enter the appropriate query for selecting the data to be exported to the specified Impala table or directory.

Select this check box to use the Impala Partition clause in loading or inserting data in a Impala table. You need to enter the partition keys and their values to be used in the field that appears.

For example, enter contry='US', state='CA'. This makes a partition clause reading Partition (contry='US', state='CA'), that is to say, a US and CA partition.

Also, it is recommended to select the Create partition if not exist check box that appears to ensure that you will not create a duplicate partition.

Die on error

Select this check box to kill the Job when an error occurs.

tStatCatcher Statistics

Select this check box to collect log data at the component level.

Global Variables

QUERY: the query statement being processed. This is a Flow variable and it returns a string.

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 rule

This component works standalone.

Dynamic settings

Click the [+] button to add a row in the table and fill the Code field with a context variable to choose your database connection dynamically from multiple connections planned in your Job. This feature is useful when you need to access database tables having the same data structure but in different databases, especially when you are working in an environment where you cannot change your Job settings, for example, when your Job has to be deployed and executed independent of Talend Studio.

The Dynamic settings table is available only when the Use an existing connection check box is selected in the Basic settings view. Once a dynamic parameter is defined, the Component List box in the Basic settings view becomes unusable.

For examples on using dynamic parameters, see and . For more information on Dynamic settings and context variables, see Talend Studio User Guide.

Prerequisites

The Hadoop distribution must be properly installed, so as to guarantee the interaction with Talend Studio . The following list presents MapR related information for example.

• Ensure that you have installed the MapR client in the machine where the Studio is, and added the MapR client library to the PATH variable of that machine. According to MapR's documentation, the library or libraries of a MapR client corresponding to each OS version can be found under MAPR_INSTALL\ hadoop\hadoop-VERSION\lib\native. For example, the library for Windows is \lib\native\MapRClient.dll in the MapR client jar file. For further information, see the following link from MapR: http://www.mapr.com/blog/basic-notes-on-configuring-eclipse-as-a-hadoop-development-environment-for-mapr.

  Without adding the specified library or libraries, you may encounter the following error: no MapRClient in java.library.path.

• Set the -Djava.library.path argument, for example, in the Job Run VM arguments area of the Run/Debug view in the Preferences dialog box in the Window menu. This argument provides to the Studio the path to the native library of that MapR client. This allows the subscription-based users to make full use of the Data viewer to view locally in the Studio the data stored in MapR.

For further information about how to install a Hadoop distribution, see the manuals corresponding to the Hadoop distribution you are using.