The Cassandra Output step provides a number of options that control what and how data is written to the target Cassandra keyspace (database). This tab contains the following connection details and basic query information (in particular, how to connect to Cassandra and execute a CQL query to retrieve rows from a table):
| Option | Description |
|---|---|
| Table to write to | Specify which the table (column family) to write the incoming rows. |
| Get table names | Click if you want to populate the Table to write to list with names of all the tables that exist in the specified keyspace. |
| Consistency level |
Specify an explicit write consistency. The following values are valid:
The Cassandra default is ONE. |
| Commit batch size | Specify the number of rows to send with each commit |
| Batch insert timeout | Specify the number of milliseconds to wait for a batch to completely insert before splitting into smaller sub-batches. You must specify a value lower than Socket timeout or leave empty for no timeout. |
| Sub batch size | Specify the sub-batch size (in number of rows) if the batch must be split because Batch insert timeout is reached. |
| Insert unlogged batches | Select if you want to use non-atomic batch writing. By default, batches are atomic (if any of the batch succeeds, all of it will succeed). Select this option to remove the atomic restriction. |
| Time to live (TTL) | Specify the amount of time in which to write a column. If the time expires, that column is deleted. |
| Incoming field to use as the key | Specify which incoming field to use as the key. You can use to specify the key from the names of incoming PDI transformation fields. |
| Select fields | Select from a list of incoming PDI transformation fields to specify as the Incoming field to use as the key. |
| Use CQL version 3 | Queries with CQL version 3. |
| Use Thrift I/O | Uses Thrift I/O. |
| Show schema | Click to open a dialog box that shows metadata for the table specified in Table to write to. |
Important: Cassandra Output does not check the types of incoming columns against matching columns in the Cassandra
metadata. Incoming values are formatted into appropriate string values for use in a textual CQL INSERT statement according to PDI's field metadata. If resulting values cannot be parsed by the Cassandra column validator for a particular column then an error occurs.
Cassandra Output converts PDI's dense row format into sparse data by ignoring incoming null field values.