tRedshiftUnload – Docs for ESB 5.x

Component family

Databases/Amazon Redshift

Function

This component runs a specified query in Amazon Redshift and then unloads the result of
the query to one or more files on Amazon S3.

Purpose

This component allows you to unload data on Amazon Redshift to files on Amazon
S3.

Basic settings

Property Type

Either Built-In or Repository.

Since version 5.6, both the Built-In mode and the Repository mode are
available in any of the Talend solutions.

Built-In: No property data stored
centrally.

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

Database settings

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.

Host

Type in the IP address or hostname of the database server.

Port

Type in the listening port number of the database server.

Database

Type in the name of the database.

Schema

Type in the name of the schema.

Username and Password

Type in the database user authentication data.

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.

Table Name

Type in the name of the table from which the data will be
read.

Schema and Edit schema

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.

Since version 5.6, both the Built-In mode and the Repository mode are
available in any of the Talend solutions.

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.

Click Edit schema to make changes to the schema. If the
current schema is of the Repository type, three options are
available:

Query Type and Query

Enter the database query paying particularly attention to the proper sequence of the
fields in order to match the schema definition.

Guess Query

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

S3 Setting

Access Key

Specify the Access Key ID that uniquely identifies an AWS Account.
For how to get your Access Key and Access Secret, visit Getting Your AWS Access Keys.

Secret Key

Specify the Secret Access Key, constituting the security
credentials in combination with the access Key.

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

Bucket

Type in the name of the Amazon S3 bucket to which the data is unloaded.

Key prefix

Type in the name prefix for the unload files on Amazon S3. By default, the unload files
are written per slice of the Redshift cluster and the file names are
written in the format
<object_path>/<name_prefix><slice-number>_part_<file-number>.

Advanced settings

File type

Select the type of the unload files on Amazon S3 from the list:

Fields terminated by

Enter the character used to separate fields.

This field appears only when Delimited file
or CSV is selected from the File type list.

Enclosed by

Select the character in a pair of which the fields are
enclosed.

This list appears only when Delimited file
or CSV is selected from the File type list.

Fixed width mapping

Enter a string that specifies a user-defined column label and
column width between double quotation marks. The format of the
string is:

ColumnLabel1:ColumnWidth1,ColumnLabel2:ColumnWidth2,....

Note that the column label in the string has no relation to the
table column name and it can be either a text string or an integer.
The order of the label/width pairs must match the order of the table
columns exactly.

This field appears only when Fixed
width is selected from the File
type list.

Compressed by

Select this check box and from the list displayed select the
compression type of the files.

Encrypt

Select this check box to encrypt unload file(s) using Amazon S3 client-side encryption.
For more information, see Unloading Encrypted Data Files.

Encryption key

Enter the encryption key used to encrypt unload file(s).

This field appears only when the Encrypt check box is selected.

Specify null string

Select this check box and from the list displayed select a string
that represents a null value in unload files.

Escape

Select this check box to place an escape character () before every occurrence of the
following characters for CHAR and VARCHAR columns in the delimited
unload files: linefeed (
), carriage return (
), the delimiter
character specified for the unloaded data, the escape character (),
a quote character (” or ‘).

Overwrite s3 object if exist

Select this check box to overwrite the existing Amazon S3 object
files.

Parallel

Select this check box to write data in parallel to multiple unload
files on Amazon S3 according to the number of slices in the Redshift
cluster.

tStatCatcher Statistics

Select this check box to gather the Job processing metadata at the
Job level as well as at each component level.

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 more information on Dynamic settings and context
variables, see Talend Studio User Guide.

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

This component covers all possible SQL queries for the Amazon Redshift database.

Log4j

The activity of this component can be logged using the log4j feature. For more information on this feature, see Talend Studio User
Guide.

For more information on the log4j logging levels, see the Apache documentation at http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/Level.html.