July 30, 2023

tELTHiveOutput – Docs for ESB 7.x

tELTHiveOutput

Works alongside tELTHiveMap to write data
into the Hive table.

The three ELT Hive components are closely related, in terms
of their operating conditions. These components should be used to handle Hive DB schemas
to generate Insert statements, including clauses, which are to be executed in the DB
output table defined.

This component executes the query built by the preceding tELTHiveMap component to write data into
the specified Hive table.

tELTHiveOutput Standard properties

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

The Standard
tELTHiveOutput component belongs to the ELT family.

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

Basic settings

Action on data

Select the action to be performed on the data to be written in the Hive
table.

With the Insert option, the data to be
written in the Hive table will be appended to the existing data if there is any.

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.

 

Built-In: You create and store the schema locally for this component
only.

Repository: You have already created the schema and stored it in the
Repository. You can reuse it in various projects and Job designs.

Edit schema

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.

Default table name

Enter the default name of the output table you want to write
data in.

Default schema name

Enter the name of the default database schema to which the
output table to be used is related to.

Table name from connection name is
variable

Select this check box when the name of the connection to this
component is set to a variable, such as a context variable.

Use different table name

Select this check box to define a different output table name,
between double quotation marks, in the Table
name
field that appears.

If this table is related to a different database schema from
the default one, you also need to enter the name of that database schema. The
syntax is schema_name.table_name.

The target table uses the Parquet format

If the table in which you need to write data is a
PARQUET
table, select this check box.

Then from the Compression list that appears,
select the compression mode you need to use to handle the
PARQUET
file. The default mode is Uncompressed.

Field Partition

In Partition Column,
enter the name, without any quotation marks, of the partition column of the
Hive table you want to write data in.

In Partition Value,
enter the value you want to use, in single quotation marks, for its
corresponding partition column.

Mapping

Specify the metadata mapping file
for the database to be used. The metadata mapping file is used for the data
type conversion between database and Java. For more information about the
metadata mapping, see the related documentation for Type mapping.

Advanced settings

tStatCatcher Statistics

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

Global Variables

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

Usage rule

tELTHiveMap is used along with a
tELTHiveInput and tELTHiveOutput. Note that the Output link to be
used with these components must correspond strictly to the syntax of the table
name.

If the Studio used to connect to a Hive database is operated on Windows,
you must manually create a folder called tmp in the root of the
disk where this Studio is installed.

Note:

The ELT components do not handle actual data flow but only
schema information.

Usage with Dataproc

The ELT Hive components require Tez to be installed on
the Google Cloud Dataproc cluster to be used.

  • Use the initialization action explained in this Google Cloud Platform
    documentation: Apache Tez on Dataproc.

  • For more details about the general concept of the initialization actions in
    a Google Cloud Dataproc cluster, see the related Google documentation: Initialization actions.


Document get from Talend https://help.talend.com
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