During processing of a data flow work item with the state management option set to Database, the following error is displayed:

DNodeException: Unable to obtain session. Cassandra hasn't been started or is unavailable.

Cause

No node has been defined in the Decision Data Store service.

Decision Data Store service that contains a working decision data node

Solution

Perform the following steps to define a decision data store node:

1. Click Designer Studio > Decisioninig > Infrastructure > Services > Decision Data Store.
2. Click Add node.
3. Select an available Pega 7 Platform node to become a decision data store node.
4. Click Submit. The status of the new node is JOINING.
5. Click Refresh to ensure that the status of the decision data store node changes to NORMAL.