Contributed by Michael Cunanan, Paul Bayliss, and Michal Wozniak
Applies to Pega Platform™ 8.x (all releases)
Symptoms
Pega application dataflows fail with a Cassandra error, making the application unusable. The issue is intermittent and was reported for production environments in which the Pega deployment uses an external Cassandra database system with three nodes in normal state.
The issue was observed after Cassandra 3.11 was upgraded to Cassandra 4.0 and after the Cassandra-Driver-Core-3.1.2.jar file was imported into a Pega Platform version 8.4.4 environment. Approximately two weeks after the upgrade to Cassandra 4.0 and the import of the Cassandra-Driver-Core-3.1.2.jar file, the issue arises intermittently.
Errors
Caused by: com.datastax.driver.core.exceptions.ProtocolError: An unexpected protocol error occurred on host <server IP address>. This is a bug in this library, please report: Must not send frame with WARNING flag for native protocol version < 4<CR> at . . .
Explanation
User error
Third-party defect
Upgrading to Cassandra 4.0 in an environment running Pega Platform version 8.4.4 will cause problems because Pega Platform version 8.4.x does not support Cassandra 4.0.
Pega Platform is validated for Cassandra 4.0 for Pega Platform versions 8.7 and 8.8.
The Decision Data Store (DDS) code specifies the use of Cassandra CQL Protocol Version 3 on an unsupported version of Cassandra 4.0 that conflicts with Pega Platform version 8.4.4 and later Pega Platform releases.
Environments
The problem was reported for Pega Platform 8.4.4, but it can arise in any version of Pega Platform 8.
Solutions
Choose the solution that best meets your needs.
Pega Platform version 8.4.4
If you are using Pega Platform version 8.4.4, obtain and install HFIX-86163:
Go to My Support Portal and click Create a ticket > Request an Existing Hotfix.
HFIX-86163 provides a new Dynamic System Setting (DSS) that you can customize:
Owning Ruleset: Pega-DecisionEngine
Setting Purpose: dnode/cassandra_override_protocol_version
Value: V3
V3 is the current default value. Allowed values depend on the Cassandra server version that is being used and the format is a plain text string containing the Cassandra version number, for example, V4.
Other Pega Platform versions
If you are using other minor and patch releases of Pega Platform 8, perform the following workaround:
Upgrade your Cassandra 4.0 version to Cassandra 4.1. Cassandra 4.1 contains a core driver that does not cause DDS operations to fail.
Future Pega Platform releases
Best practice: Keep current with Pega
The issue will be corrected in future patch releases of Pega Platform versions 8.7 and 8.8 and in the future major release, Pega Platform ’23.
Watch the Pega Support Center Pega Platform Resolved Issues.
After Pega Platform ’23 is released, search for ISSUE-797477.
For Pega Platform version 8.7.6, search for ISSUE-797627.
For Pega Platform version 8.8.3, search for ISSUE-797626.
Related content
Pega Documentation
External Cassandra in your deployment
Pega Platform Support Guide > Client-Managed Solutions > Decision Data Store > Cassandra
