Identify the root cause of degraded performance by completing corresponding monitoring activities. Learn about the most commonly encountered Cassandra issues and how to address them.

• Addressing common issues

  Learn about the most commonly encountered Cassandra issues and how to address them.

• Checking the node status

  Check the status of Decision Data Store (DDS) nodes, for example, to troubleshoot Cassandra-related failures listed in Pega Platform logs.

• Getting the count of Cassandra table records

  Extract the estimated number of records in a Cassandra cluster to verify that the data model is correct, or to troubleshoot slow response times.

• Investigating compaction issues

  If you notice an increase in the amount of data that Cassandra stores in SSTables, or if you receive error messages about failed compactions, check the time of the last successful compaction for selected SSTables.

• Monitoring Cassandra errors and warnings

  Check Cassandra logs for errors and warnings when you notice performance issues such as low latency, or when you receive Cassandra-related Pega Platform alerts.

• Recovering a node (deprecated)

  In an on-premises or client-managed cloud, you can restart a node that is unavailable by performing a node recovery procedure. For nodes running in Pega Cloud environments, this task is not supported; the deployment automatically manages any required node recovery.

• Removing DDS nodes from a Cassandra cluster

  Reduce the size of a Cassandra cluster by permanently removing Decision Data Store (DDS) nodes from the cluster. This procedure allows the cluster to rebalance itself and ensures that the removed nodes are not reintroduced into the cluster.

• Verifying the available disk space

  Ensure the stability and availability of a Cassandra deployment on Pega Platform by providing enough disk space to run compactions.

• Verifying the keyspace replication factor

  Troubleshoot keyspace-related errors, such as incorrect replication, by checking whether a specific keyspace exists and whether the keyspace belongs to the correct data center.

• Verifying the status of ports

  In Pega Platform 7.2.1 and later, check if ports 7000 and 9042 listen to an IP address which is accessible from the other nodes.