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Component Family
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Big Data / Impala
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Function
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tImpalaConnection opens a
connection to an Impala database.
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Purpose
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This component allows you to establish an Impala connection to be
reused by other Impala components in your Job.
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Basic settings
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Property type
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Either Built-in or Repository.
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Built-in: No property data stored
centrally.
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Repository: Select the repository
file in which the properties are stored. The fields that follow are
completed automatically using the data retrieved.
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Version
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Distribution
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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:
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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 WebHCat service, the HD Insight service and the Windows Azure
Storage service of that cluster in the areas that are displayed. A demonstration
video about how to configure this connection is available in the following link:
https://www.youtube.com/watch?v=A3QTT6VsNoM
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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.
In order to connect to a custom distribution, once selecting Custom, click the  button to display the dialog box in which you can
alternatively:
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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.
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Select Import from zip to import a custom
distribution zip that, for example, you can download from http://www.talendforge.org/exchange/index.php.
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 an step-by-step example about how to connect to a custom distribution and
share this connection, see Connecting to a custom Hadoop distribution.
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Impala version
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Select the version of the Hadoop distribution you are using. The available options vary
depending on the component you are using. Along with the evolution of Hadoop, please note
the following changes:
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If you use Hortonworks Data Platform V2.2, the
configuration files of your cluster might be using environment variables such as
${hdp.version}. If this is your situation, you
need to set the mapreduce.application.framework.path property in the Hadoop properties table of this component with the path value
explicitly pointing to the MapReduce framework archive of your cluster. For
example:
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mapreduce.application.framework.path=/hdp/apps/2.2.0.0-2041/mapreduce/mapreduce.tar.gz#mr-framework |
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If you use Hortonworks Data Platform V2.0.0, the
type of the operating system for running the distribution and a Talend
Job must be the same, such as Windows or Linux. Otherwise, you have to use Talend
Jobserver to execute the Job in the same type of operating system in which the
Hortonworks Data Platform V2.0.0 distribution you
are using is run. For further information about Talend Jobserver, see
Talend Installation
and Upgrade Guide.
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Host
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Database server IP address.
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Port
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DB server listening port.
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Database
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Fill this field with the name of the database.
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Username
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DB user authentication data.
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Authentication
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Use kerberos authentication
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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.
This check box is available depending on the Hadoop distribution you are connecting
to.
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Advanced settings
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tStatCatcher Statistics
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Select this check box to collect the log data at a component
level.
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Global Variables
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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.
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Usage
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This component is generally used with other Impala components, particularly tImpalaClose.
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Prerequisites
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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.
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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.
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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. 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
set this argument, see the section describing how to view data of Talend Big Data Getting Started Guide.
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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Limitation
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n/a
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