tCassandraOutputBulkExec properties - 6.3

Talend Open Studio for Big Data Components Reference Guide

EnrichVersion
6.3
EnrichProdName
Talend Open Studio for Big Data
task
Data Governance
Data Quality and Preparation
Design and Development
EnrichPlatform
Talend Studio

Component family

Big Data / Cassandra

 

Basic settings

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.

For more details, see the article Verifying default values in a retrieved schema on Talend Help Center (https://help.talend.com).

 

Table type

Select the type of the data model to be used for the table to be created. It can be CQL (actually CQL3) or non-CQL (the legacy thrift-based API of Cassandra before CQL3).

This drop-down list is available only when the DB version you are using is Cassandra 2.0.0. For the Cassandra versions later than 2.0.0, CQL becomes the only model used by this component and so this list is no longer available.

 

DB Version

Select the Cassandra version you are using.

Warning

  • For Cassandra 1.1.2, only local visit on Linux is supported.

  • For Cassandra 1.2.2, make sure that the server and the client run on the same operating system.

  • Cassandra 2.0.0 only works with JVM1.7.

 

Host

Hostname or IP address of the Cassandra server.

 

Port

Listening port number of the Cassandra server.

 

Required authentication

Select this check box to provide credentials for the Cassandra authentication.

Warning

This check box will not appear if you select Cassandra 1.1.2 from theDB Version list.

 

Username

Fill in this field with the username for the Cassandra authentication.

 

Password

Fill in this field with the password for the Cassandra authentication.

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.

 

Keyspace

Type in the name of the keyspace into which you want to write the SSTable.

 

Column family

Type in the name of the column family into which you want to write the SSTable.

 

Partitioner

Select the partitioner which determines how the data is distributed across the Cassandra cluster.

  • Random: default partitioner in Cassandra 1.1 and earlier.

  • Murmur3: default partitioner in Cassandra 1.2.

  • Order preserving: not recommended because it assumes keys are UTF8 strings.

For more information about the partitioner, see http://wiki.apache.org/cassandra/Partitioners.

 

Schema statement

Enter the statement to define the schema of the column family to be used or to be created on the fly.

  • This statement is a Cassandra prepared statement, which stores query results locally in the SSTable directory you define with this component before sending them to the server. For further information about the prepared statements, see Prepared statements.

  • A Cassandra column family is a container for a collection of rows of records that have a similar kind. Its schema must contain strictly the same columns as the component schema you have defined, that is to say, the column names and the order of the columns in both the schemas must be identical.

An example of this schema statement is provided in the Schema statement field:

create table ks.tb (id int, name text, birthday timestamp, primary key(id, birthday)) with clustering order by (birthday desc)

It will create a column family called tb containing the id, the name and the birthday columns under the keyspace ks.

For further information about a column family, see Standard column family.

This field is available only when the version of your Cassandra database is later than 2.0.0. When it is 2.0.0, it is available only when you have selected CQL from the Table type drop-down list.

 

Insert statement

Enter the statement to instruct how to write the data from the input flow into the columns of the column family to be used.

This statement is a Cassandra prepared statement, which stores query results locally in the SSTable directory you define with this component before sending them to the server. For further information about the prepared statements, see Prepared statements.

An example of this insert statement is provided in the Insert statement field:

insert into ks.tb (id, name, birthday) values (?, ?, ?)

It will write data into the id, the name and the birthday columns, respectively, of a column family called tb in the keyspace ks. The question marks in the statement are the bind variable markers for the three columns. For further information about bind variables and their usage, see Bound parameters and Parameterized queries.

This field is available only when the version of your Cassandra database is later than 2.0.0. When it is 2.0.0, it is available only when you have selected CQL from the Table type drop-down list.

 

Column name comparator

Select the data type for the column names, which is used to sort columns.

For more information about the comparators, see http://www.datastax.com/docs/1.1/ddl/column_family#about-data-types-comparators-and-validators.

 

SSTable directory

Specify the local directory for the SSTable. Note that the complete path to the SSTable will be the local directory appended by the specified keyspace name and column family name.

For example, if you set the local directory to /home/talend/sstable, and specify testk as the keyspace name and testc as the column family name, the complete path to the SSTable will be /home/talend/sstable/testk/testc/.

 

Buffer size

Specify what size the SSTable must reach before it is written into Cassandra.

Advanced settings

tStatCatcher Statistics

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

This component is mainly used when no particular transformation is required on the data to be loaded into the database.

Limitation

Currently, the execution of this component ends the entire Job.