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tImpalaRow Standard properties

These properties are used to configure tImpalaRow running in the Standard Job framework.

The Standard tImpalaRow component belongs to the Big Data family.

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

Basic settings

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 drop-down list, select the desired connection component to reuse the connection details you already defined.

Information noteNote: When a Job contains the parent Job and the child Job, if you need to share an existing connection between the two levels, for example, to share the connection created by the parent Job with the child Job, you have to:

  1. In the parent level, register the database connection to be shared in the Basic settings view of the connection component which creates that very database connection.

  2. In the child level, use a dedicated connection component to read that registered database connection.

For an example about how to share a database connection across Job levels, see Talend Studio User Guide.

Distribution

Select the cluster you are using from the drop-down list. The options in the list vary depending on the component you are using. Among these options, the following ones requires specific configuration:

  • If available in this Distribution drop-down list, the Microsoft HD Insight option allows you to use a Microsoft HD Insight cluster. For this purpose, you need to configure the connections to the HD Insight cluster and the Windows Azure Storage service of that cluster in the areas that are displayed. For detailed explanation about these parameters, search for configuring the connection manually on Talend Help Center (https://help.talend.com).

  • If you select Amazon EMR, find more details about Amazon EMR getting started in Talend Help Center (https://help.talend.com).

  • The Custom option allows you to connect to a cluster different from any of the distributions given in this list, that is to say, to connect to a cluster not officially supported by Talend .

  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.

    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 Hortonworks.

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

Enter the name of the database.

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.

Username and Password

Enter the database user authentication data to authenticate using LDAP.

To enter the password, click the […] button next to the password field, and then in the pop-up dialog box enter the password between double quotes and click OK to save the settings.

These parameters are not available when you select the Use kerberos authentication check box.

Use kerberos authentication

If you are accessing an Impala system running with Kerberos security, select this check box and then enter the Kerberos principal of this Impala system.

  • If this cluster is a MapR cluster of the version 5.0.0 or later, you can set the MapR ticket authentication configuration in addition or as an alternative by following the explanation in Connecting to a security-enabled MapR.

    Keep in mind that this configuration generates a new MapR security ticket for the username defined in the Job in each execution. If you need to reuse an existing ticket issued for the same username, leave both the Force MapR ticket authentication check box and the Use Kerberos authentication check box clear, and then MapR should be able to automatically find that ticket on the fly.

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

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: The schema is created and stored locally for this component only. Related topic: see Talend Studio User Guide.

 

Repository: The schema already exists and is stored in the Repository, hence can be reused. Related topic: see Talend Studio User Guide.

Table Name

Name of the table to be processed.

Query type

Either Built-in or Repository.

 

Built-in: Fill in manually the query statement or build it graphically using SQLBuilder

 

Repository: Select the relevant query stored in the Repository. The Query field gets accordingly filled in.

Guess Query

Click the Guess Query button to generate the query which corresponds to your table schema in the Query field.

Query

Enter your DB query paying particularly attention to properly sequence the fields in order to match the schema definition.

Die on error

This check box is selected by default. Clear the check box to skip the row on error and complete the process for error-free rows. If needed, you can retrieve the rows on error via a Row > Rejects link.

Advanced settings

Propagate QUERY's recordset

Select this check box to insert the result of the query into a COLUMN of the current flow. Select this column from the use column list.

Information noteNote:

This option allows the component to have a different schema from that of the preceding component. Moreover, the column that holds the QUERY's recordset should be set to the type of Object and this component is usually followed by tParseRecordSet.

tStatCatcher Statistics

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

Global Variables

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

Usage rule

This component offers the benefit of flexible DB queries and covers all possible Impala SQL queries.

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.

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