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Component family
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MapReduce/Input
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Function
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The tS3Input component loads S3N-formatted (S3 Native
Filesystem) files into the MapReduce process you are designing.
This component, along with the MapReduce family it belongs to, appears only when you are
creating a Map/Reduce Job.
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Purpose
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tS3Input reads data from a given
S3N system (S3 Native Filesystem).
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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 where Properties are stored. The following fields are
pre-filled in using fetched data.
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Schema and Edit
Schema
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A schema is a row description. It defines the number of fields 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:
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View schema: choose this option to view the
schema only.
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Change to built-in property: choose this option
to change the schema to Built-in for local
changes.
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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.
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Built-In: You create and store the schema locally for this
component only. Related topic: see Talend Studio
User Guide.
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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.
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Bucket and Folder
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Enter the bucket name and its folder in which you need to write data. You need to separate
the bucket name and the folder name using a slash (/).
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Access key and Secret
key
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Enter the authentication information required to connect to the Amazon S3 bucket to be
used.
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.
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File type
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Type
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Select the type of the file to be processed. The type of the file may be:
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Text file.
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Sequence file: a Hadoop sequence file
consists of binary key/value pairs and is suitable for the Map/Reduce framework.
For further information, see http://wiki.apache.org/hadoop/SequenceFile.
Once you select the Sequence file format, the
Key column list and the Value column list appear to allow you to select the
keys and the values of that Sequence file to be processed.
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Row separator
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Enter the separator used to identify the end of a row.
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Field separator
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Enter character, string or regular expression to separate fields for the transferred
data.
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Header
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Enter the number of rows to be skipped in the beginning of file.
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Custom encoding
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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.
This option is not available for a Sequence file.
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Advanced settings
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Advanced separator (for number)
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Select this check box to change the separator used for numbers. By
default, the thousands separator is a coma (,) and the decimal separator is a period (.).
This option is not available for a Sequence file.
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Trim all column
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Select this check box to remove the leading and trailing
whitespaces from all columns. When this check box is cleared, the
Check column to trim table is
displayed, which lets you select particular columns to trim.
This option is not available for a Sequence file.
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Check column to trim
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This table is filled automatically with the schema being used. Select the check box(es)
corresponding to the column(s) to be trimmed.
This option is not available for a Sequence file.
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Enable parallel execution
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Select this check box to perform high-speed data processing, by treating multiple data flows
simultaneously. Note that this feature depends on the database or the application ability to
handle multiple inserts in parallel as well as the number of CPU affected. In the Number of parallel executions field, either:
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Enter the number of parallel executions desired.
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Press Ctrl + Space and select the appropriate
context variable from the list. For further information, see Talend Studio
User Guide.
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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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In a Talend Map/Reduce Job, it is used as a start component and requires
a transformation component as output 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, tS3Input 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.
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Hadoop Connection
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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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