tCassandraOutput properties for Apache Spark Streaming

Property type

Either Built-In or Repository.

Built-In: No property data stored centrally.

Repository: Select the repository file where the properties are stored.

Sync columns

Click this button to retrieve schema from the previous component connected in the Job.

Keyspace

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

Action on keyspace

Select the operation you want to perform on the keyspace to be used:

• None: No operation is carried out.

• Drop and create keyspace: The keyspace is removed and created again.

• Create keyspace: The keyspace does not exist and gets created.

• Create keyspace if not exists: A keyspace gets created if it does not exist.

• Drop keyspace if exists and create: The keyspace is removed if it already exists and created again.

Column family

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

Action on column family

Select the operation you want to perform on the column family to be used:

• None: no operation is carried out.

• Create column family if not exists: a column family gets created if it does not exist.

• Drop column family if exists and create: the column family is removed if it already exists and created again.

• Truncate column family: all data from the column family is permanently removed.

This list is available only when you have selected Update, Upsert or Insert from the Action on data drop-down list.

Action on data

On the data of the table defined, you can perform:

• Upsert: insert the columns if they do not exist or update the existing columns.

  With this action, the columns to be defined in the schema must use lower case in their names, while the names you put in the DB column column of the schema must be identical with their equivalents in the target table, including the letter cases.

• Insert: insert the columns if they do not exist. This action also updates the existing ones.

• Update: update the existing columns or add the columns that do not exist. This action does not support the Counter Cassandra data type.

• Delete: remove columns corresponding to the input flow.

For more advanced actions, use the Advanced settings view.

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. When you create a Spark Job, avoid the reserved word line when naming the fields.

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.

The schema of this component does not support the Object type and the List type.

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.

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 information, see Retrieving table schemas.

Configuration

The following list presents the numerical values you can put and the consistency levels they signify:

When a row is added to the table, you need to click the new row in the Property name column to display the list of the available properties and select the property or properties to be customized. For further information about each of these properties, see the Tuning section in the following link: https://github.com/datastax/spark-cassandra-connector/blob/master/doc/5_saving.md.

Use unlogged batch

Select this check box to handle data in batch but with Cassandra's UNLOGGED approach. This feature is available to the following three actions: Insert, Update and Delete.

The ideal situation to use batches with Cassandra is when a small number of tables must synchronize the data to be inserted or updated.

In this UNLOGGED approach, the Job does not write batches into Cassandra's batchlog system and thus avoids the performance issue incurred by this writing. For further information about Cassandra BATCH statement and UNLOGGED approach, see Batches.

Insert if not exists

Select this check box to insert rows. This row insertion takes place only when they do not exist in the target table.

This feature is available to the Insert action only.

Delete if exists

Select this check box to remove from the target table only the rows that have the same records in the incoming flow.

This feature is available only to the Delete action.

Use TTL

Select this check box to write the TTL data in the target table. In the column list that is displayed, you need to select the column to be used as the TTL column. The DB type of this column must be Int.

This feature is available to the Insert action and the Update action only.

Use Timestamp

Select this check box to write the timestamp data in the target table. In the column list that is displayed, you need to select the column to be used to store the timestamp data. The DB type of this column must be BigInt.

This feature is available to the following actions: Insert, Update and Delete.

IF condition

Add the condition to be met for the Update or the Delete action to take place. This condition allows you to be more precise about the columns to be updated or deleted.

Special assignment operation

Complete this table to construct advanced SET commands of Cassandra to make the Update action more specific. For example, add a record to the beginning or a particular position of a given column.

Row key in the List type

Select the column to be used to construct the WHERE clause of Cassandra to perform the Update or the Delete action on only selected rows. The column(s) to be used in this table should be from the set of the Primary key columns of the Cassandra table.

Delete collection column based on postion/key

Select the column to be used as reference to locate the particular row(s) to be removed.

This feature is available only to the Delete action.

Usage rule

This component is used as an end component and requires an input link.

This component should use one and only one tCassandraConfiguration component present in the same Job to connect to Cassandra. More than one tCassandraConfiguration components present in the same Job fail the execution of the Job.

This component, along with the Spark Batch component Palette it belongs to, appears only when you are creating a Spark Batch Job.

Note that in this documentation, unless otherwise explicitly stated, a scenario presents only Standard Jobs, that is to say traditional Talend data integration Jobs.

Spark Connection

This connection is effective on a per-Job basis.