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.

   Note:

   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 Connecting to a custom Hadoop distribution.

Impala version

Host

Database server IP address.

Port

Listening port number of DB server.

Database

Fill this field with the name of the database.

Username and
Password

DB user authentication data.

Use kerberos authentication

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. The schema is either Built-In or stored remotely in the Repository.

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. Related topic: see
Talend Studio

User Guide.

Repository: You have already created
the schema and stored it in the Repository. You can reuse it in various projects and
Job designs. Related topic: see
Talend Studio

User Guide.

When the schema to be reused has default values that are integers or
functions, ensure that these default values are not enclosed within quotation marks. If
they are, you must remove the quotation marks manually.

You can find more details about how to verify default
values in retrieved schema in Talend Help Center (https://help.talend.com).

Table Name

Name of the table to be created.

Action on table

Select the action to be carried out for creating a table.

Format

Select the data format to which the table to be created is
dedicated.

The available data formats vary depending on the version of the
Hadoop distribution you are using.

Select this check box to add partition columns to the table to be
created. Once selecting it, you need to define the schema of the
partition columns you need to add.

Set file location

If you want to create an Impala table in a directory other than the default one, select
this check box and enter the directory in HDFS you want to use to
hold the table content.

This is typical useful when you need to create an external Impala
table by selecting the Create an external
table check box in the Advanced
settings tab.

Use S3 endpoint

The Use S3 endpoint check box is
displayed when you have selected the Set file
location check box to create an external Impala table.

Since an Impala table created in S3 is actually an external table, this Use S3 endpoint check box must be used
with the Create an external table
case being selected.

Like table

Select this check box and enter the name of the Impala table you
want to copy. This allows you to copy the definition of an existing
table without copying its data.

For further information about the Like parameter, see Cloudera’s information about
Impala’s Data Definition Language.

Create an external table

Select this check box to make the table to be created an external
Impala table. This kind of Impala table leaves the raw data where it is
if the data is in HDFS.

An external table is usually the better choice for accessing
shared data existing in a file system.

For further information about an external Impala table, see Cloudera’s documentation
about Impala.

Table comment

Enter the description you want to use for the table to be
created.

As select

Select this check box and enter the As select statement for creating an
Impala table that is based on a Select
statement.

Table properties

Add any custom Impala table properties you want to override the
default ones used by the Hadoop engine of the Studio.

tStatCatcher Statistics

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

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 rule

This component works standalone.

Row format

Set Delimited row format

Die on error

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 Scenario: Reading data from databases through context-based dynamic connections and Scenario: Reading data from different MySQL databases using dynamically loaded connection parameters. 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
  hadoophadoop-VERSIONlib
  ative. For example, the library for
  Windows is lib
  ativeMapRClient.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.